Init lali programming language.

28 files changed, 6541 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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+lali
+liblali.a
+*.o
+README.html
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..f288702
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
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+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/LICENSES/GFDL-1.3-or-later.txt b/LICENSES/GFDL-1.3-or-later.txt
new file mode 100644
index 0000000..857214d
--- /dev/null
+++ b/LICENSES/GFDL-1.3-or-later.txt
@@ -0,0 +1,451 @@
+
+                GNU Free Documentation License
+                 Version 1.3, 3 November 2008
+
+
+ Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
+     <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+0. PREAMBLE
+
+The purpose of this License is to make a manual, textbook, or other
+functional and useful document "free" in the sense of freedom: to
+assure everyone the effective freedom to copy and redistribute it,
+with or without modifying it, either commercially or noncommercially.
+Secondarily, this License preserves for the author and publisher a way
+to get credit for their work, while not being considered responsible
+for modifications made by others.
+
+This License is a kind of "copyleft", which means that derivative
+works of the document must themselves be free in the same sense.  It
+complements the GNU General Public License, which is a copyleft
+license designed for free software.
+
+We have designed this License in order to use it for manuals for free
+software, because free software needs free documentation: a free
+program should come with manuals providing the same freedoms that the
+software does.  But this License is not limited to software manuals;
+it can be used for any textual work, regardless of subject matter or
+whether it is published as a printed book.  We recommend this License
+principally for works whose purpose is instruction or reference.
+
+
+1. APPLICABILITY AND DEFINITIONS
+
+This License applies to any manual or other work, in any medium, that
+contains a notice placed by the copyright holder saying it can be
+distributed under the terms of this License.  Such a notice grants a
+world-wide, royalty-free license, unlimited in duration, to use that
+work under the conditions stated herein.  The "Document", below,
+refers to any such manual or work.  Any member of the public is a
+licensee, and is addressed as "you".  You accept the license if you
+copy, modify or distribute the work in a way requiring permission
+under copyright law.
+
+A "Modified Version" of the Document means any work containing the
+Document or a portion of it, either copied verbatim, or with
+modifications and/or translated into another language.
+
+A "Secondary Section" is a named appendix or a front-matter section of
+the Document that deals exclusively with the relationship of the
+publishers or authors of the Document to the Document's overall
+subject (or to related matters) and contains nothing that could fall
+directly within that overall subject.  (Thus, if the Document is in
+part a textbook of mathematics, a Secondary Section may not explain
+any mathematics.)  The relationship could be a matter of historical
+connection with the subject or with related matters, or of legal,
+commercial, philosophical, ethical or political position regarding
+them.
+
+The "Invariant Sections" are certain Secondary Sections whose titles
+are designated, as being those of Invariant Sections, in the notice
+that says that the Document is released under this License.  If a
+section does not fit the above definition of Secondary then it is not
+allowed to be designated as Invariant.  The Document may contain zero
+Invariant Sections.  If the Document does not identify any Invariant
+Sections then there are none.
+
+The "Cover Texts" are certain short passages of text that are listed,
+as Front-Cover Texts or Back-Cover Texts, in the notice that says that
+the Document is released under this License.  A Front-Cover Text may
+be at most 5 words, and a Back-Cover Text may be at most 25 words.
+
+A "Transparent" copy of the Document means a machine-readable copy,
+represented in a format whose specification is available to the
+general public, that is suitable for revising the document
+straightforwardly with generic text editors or (for images composed of
+pixels) generic paint programs or (for drawings) some widely available
+drawing editor, and that is suitable for input to text formatters or
+for automatic translation to a variety of formats suitable for input
+to text formatters.  A copy made in an otherwise Transparent file
+format whose markup, or absence of markup, has been arranged to thwart
+or discourage subsequent modification by readers is not Transparent.
+An image format is not Transparent if used for any substantial amount
+of text.  A copy that is not "Transparent" is called "Opaque".
+
+Examples of suitable formats for Transparent copies include plain
+ASCII without markup, Texinfo input format, LaTeX input format, SGML
+or XML using a publicly available DTD, and standard-conforming simple
+HTML, PostScript or PDF designed for human modification.  Examples of
+transparent image formats include PNG, XCF and JPG.  Opaque formats
+include proprietary formats that can be read and edited only by
+proprietary word processors, SGML or XML for which the DTD and/or
+processing tools are not generally available, and the
+machine-generated HTML, PostScript or PDF produced by some word
+processors for output purposes only.
+
+The "Title Page" means, for a printed book, the title page itself,
+plus such following pages as are needed to hold, legibly, the material
+this License requires to appear in the title page.  For works in
+formats which do not have any title page as such, "Title Page" means
+the text near the most prominent appearance of the work's title,
+preceding the beginning of the body of the text.
+
+The "publisher" means any person or entity that distributes copies of
+the Document to the public.
+
+A section "Entitled XYZ" means a named subunit of the Document whose
+title either is precisely XYZ or contains XYZ in parentheses following
+text that translates XYZ in another language.  (Here XYZ stands for a
+specific section name mentioned below, such as "Acknowledgements",
+"Dedications", "Endorsements", or "History".)  To "Preserve the Title"
+of such a section when you modify the Document means that it remains a
+section "Entitled XYZ" according to this definition.
+
+The Document may include Warranty Disclaimers next to the notice which
+states that this License applies to the Document.  These Warranty
+Disclaimers are considered to be included by reference in this
+License, but only as regards disclaiming warranties: any other
+implication that these Warranty Disclaimers may have is void and has
+no effect on the meaning of this License.
+
+2. VERBATIM COPYING
+
+You may copy and distribute the Document in any medium, either
+commercially or noncommercially, provided that this License, the
+copyright notices, and the license notice saying this License applies
+to the Document are reproduced in all copies, and that you add no
+other conditions whatsoever to those of this License.  You may not use
+technical measures to obstruct or control the reading or further
+copying of the copies you make or distribute.  However, you may accept
+compensation in exchange for copies.  If you distribute a large enough
+number of copies you must also follow the conditions in section 3.
+
+You may also lend copies, under the same conditions stated above, and
+you may publicly display copies.
+
+
+3. COPYING IN QUANTITY
+
+If you publish printed copies (or copies in media that commonly have
+printed covers) of the Document, numbering more than 100, and the
+Document's license notice requires Cover Texts, you must enclose the
+copies in covers that carry, clearly and legibly, all these Cover
+Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
+the back cover.  Both covers must also clearly and legibly identify
+you as the publisher of these copies.  The front cover must present
+the full title with all words of the title equally prominent and
+visible.  You may add other material on the covers in addition.
+Copying with changes limited to the covers, as long as they preserve
+the title of the Document and satisfy these conditions, can be treated
+as verbatim copying in other respects.
+
+If the required texts for either cover are too voluminous to fit
+legibly, you should put the first ones listed (as many as fit
+reasonably) on the actual cover, and continue the rest onto adjacent
+pages.
+
+If you publish or distribute Opaque copies of the Document numbering
+more than 100, you must either include a machine-readable Transparent
+copy along with each Opaque copy, or state in or with each Opaque copy
+a computer-network location from which the general network-using
+public has access to download using public-standard network protocols
+a complete Transparent copy of the Document, free of added material.
+If you use the latter option, you must take reasonably prudent steps,
+when you begin distribution of Opaque copies in quantity, to ensure
+that this Transparent copy will remain thus accessible at the stated
+location until at least one year after the last time you distribute an
+Opaque copy (directly or through your agents or retailers) of that
+edition to the public.
+
+It is requested, but not required, that you contact the authors of the
+Document well before redistributing any large number of copies, to
+give them a chance to provide you with an updated version of the
+Document.
+
+
+4. MODIFICATIONS
+
+You may copy and distribute a Modified Version of the Document under
+the conditions of sections 2 and 3 above, provided that you release
+the Modified Version under precisely this License, with the Modified
+Version filling the role of the Document, thus licensing distribution
+and modification of the Modified Version to whoever possesses a copy
+of it.  In addition, you must do these things in the Modified Version:
+
+A. Use in the Title Page (and on the covers, if any) a title distinct
+   from that of the Document, and from those of previous versions
+   (which should, if there were any, be listed in the History section
+   of the Document).  You may use the same title as a previous version
+   if the original publisher of that version gives permission.
+B. List on the Title Page, as authors, one or more persons or entities
+   responsible for authorship of the modifications in the Modified
+   Version, together with at least five of the principal authors of the
+   Document (all of its principal authors, if it has fewer than five),
+   unless they release you from this requirement.
+C. State on the Title page the name of the publisher of the
+   Modified Version, as the publisher.
+D. Preserve all the copyright notices of the Document.
+E. Add an appropriate copyright notice for your modifications
+   adjacent to the other copyright notices.
+F. Include, immediately after the copyright notices, a license notice
+   giving the public permission to use the Modified Version under the
+   terms of this License, in the form shown in the Addendum below.
+G. Preserve in that license notice the full lists of Invariant Sections
+   and required Cover Texts given in the Document's license notice.
+H. Include an unaltered copy of this License.
+I. Preserve the section Entitled "History", Preserve its Title, and add
+   to it an item stating at least the title, year, new authors, and
+   publisher of the Modified Version as given on the Title Page.  If
+   there is no section Entitled "History" in the Document, create one
+   stating the title, year, authors, and publisher of the Document as
+   given on its Title Page, then add an item describing the Modified
+   Version as stated in the previous sentence.
+J. Preserve the network location, if any, given in the Document for
+   public access to a Transparent copy of the Document, and likewise
+   the network locations given in the Document for previous versions
+   it was based on.  These may be placed in the "History" section.
+   You may omit a network location for a work that was published at
+   least four years before the Document itself, or if the original
+   publisher of the version it refers to gives permission.
+K. For any section Entitled "Acknowledgements" or "Dedications",
+   Preserve the Title of the section, and preserve in the section all
+   the substance and tone of each of the contributor acknowledgements
+   and/or dedications given therein.
+L. Preserve all the Invariant Sections of the Document,
+   unaltered in their text and in their titles.  Section numbers
+   or the equivalent are not considered part of the section titles.
+M. Delete any section Entitled "Endorsements".  Such a section
+   may not be included in the Modified Version.
+N. Do not retitle any existing section to be Entitled "Endorsements"
+   or to conflict in title with any Invariant Section.
+O. Preserve any Warranty Disclaimers.
+
+If the Modified Version includes new front-matter sections or
+appendices that qualify as Secondary Sections and contain no material
+copied from the Document, you may at your option designate some or all
+of these sections as invariant.  To do this, add their titles to the
+list of Invariant Sections in the Modified Version's license notice.
+These titles must be distinct from any other section titles.
+
+You may add a section Entitled "Endorsements", provided it contains
+nothing but endorsements of your Modified Version by various
+parties--for example, statements of peer review or that the text has
+been approved by an organization as the authoritative definition of a
+standard.
+
+You may add a passage of up to five words as a Front-Cover Text, and a
+passage of up to 25 words as a Back-Cover Text, to the end of the list
+of Cover Texts in the Modified Version.  Only one passage of
+Front-Cover Text and one of Back-Cover Text may be added by (or
+through arrangements made by) any one entity.  If the Document already
+includes a cover text for the same cover, previously added by you or
+by arrangement made by the same entity you are acting on behalf of,
+you may not add another; but you may replace the old one, on explicit
+permission from the previous publisher that added the old one.
+
+The author(s) and publisher(s) of the Document do not by this License
+give permission to use their names for publicity for or to assert or
+imply endorsement of any Modified Version.
+
+
+5. COMBINING DOCUMENTS
+
+You may combine the Document with other documents released under this
+License, under the terms defined in section 4 above for modified
+versions, provided that you include in the combination all of the
+Invariant Sections of all of the original documents, unmodified, and
+list them all as Invariant Sections of your combined work in its
+license notice, and that you preserve all their Warranty Disclaimers.
+
+The combined work need only contain one copy of this License, and
+multiple identical Invariant Sections may be replaced with a single
+copy.  If there are multiple Invariant Sections with the same name but
+different contents, make the title of each such section unique by
+adding at the end of it, in parentheses, the name of the original
+author or publisher of that section if known, or else a unique number.
+Make the same adjustment to the section titles in the list of
+Invariant Sections in the license notice of the combined work.
+
+In the combination, you must combine any sections Entitled "History"
+in the various original documents, forming one section Entitled
+"History"; likewise combine any sections Entitled "Acknowledgements",
+and any sections Entitled "Dedications".  You must delete all sections
+Entitled "Endorsements".
+
+
+6. COLLECTIONS OF DOCUMENTS
+
+You may make a collection consisting of the Document and other
+documents released under this License, and replace the individual
+copies of this License in the various documents with a single copy
+that is included in the collection, provided that you follow the rules
+of this License for verbatim copying of each of the documents in all
+other respects.
+
+You may extract a single document from such a collection, and
+distribute it individually under this License, provided you insert a
+copy of this License into the extracted document, and follow this
+License in all other respects regarding verbatim copying of that
+document.
+
+
+7. AGGREGATION WITH INDEPENDENT WORKS
+
+A compilation of the Document or its derivatives with other separate
+and independent documents or works, in or on a volume of a storage or
+distribution medium, is called an "aggregate" if the copyright
+resulting from the compilation is not used to limit the legal rights
+of the compilation's users beyond what the individual works permit.
+When the Document is included in an aggregate, this License does not
+apply to the other works in the aggregate which are not themselves
+derivative works of the Document.
+
+If the Cover Text requirement of section 3 is applicable to these
+copies of the Document, then if the Document is less than one half of
+the entire aggregate, the Document's Cover Texts may be placed on
+covers that bracket the Document within the aggregate, or the
+electronic equivalent of covers if the Document is in electronic form.
+Otherwise they must appear on printed covers that bracket the whole
+aggregate.
+
+
+8. TRANSLATION
+
+Translation is considered a kind of modification, so you may
+distribute translations of the Document under the terms of section 4.
+Replacing Invariant Sections with translations requires special
+permission from their copyright holders, but you may include
+translations of some or all Invariant Sections in addition to the
+original versions of these Invariant Sections.  You may include a
+translation of this License, and all the license notices in the
+Document, and any Warranty Disclaimers, provided that you also include
+the original English version of this License and the original versions
+of those notices and disclaimers.  In case of a disagreement between
+the translation and the original version of this License or a notice
+or disclaimer, the original version will prevail.
+
+If a section in the Document is Entitled "Acknowledgements",
+"Dedications", or "History", the requirement (section 4) to Preserve
+its Title (section 1) will typically require changing the actual
+title.
+
+
+9. TERMINATION
+
+You may not copy, modify, sublicense, or distribute the Document
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense, or distribute it is void, and
+will automatically terminate your rights under this License.
+
+However, if you cease all violation of this License, then your license
+from a particular copyright holder is reinstated (a) provisionally,
+unless and until the copyright holder explicitly and finally
+terminates your license, and (b) permanently, if the copyright holder
+fails to notify you of the violation by some reasonable means prior to
+60 days after the cessation.
+
+Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, receipt of a copy of some or all of the same material does
+not give you any rights to use it.
+
+
+10. FUTURE REVISIONS OF THIS LICENSE
+
+The Free Software Foundation may publish new, revised versions of the
+GNU Free Documentation License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in
+detail to address new problems or concerns.  See
+https://www.gnu.org/licenses/.
+
+Each version of the License is given a distinguishing version number.
+If the Document specifies that a particular numbered version of this
+License "or any later version" applies to it, you have the option of
+following the terms and conditions either of that specified version or
+of any later version that has been published (not as a draft) by the
+Free Software Foundation.  If the Document does not specify a version
+number of this License, you may choose any version ever published (not
+as a draft) by the Free Software Foundation.  If the Document
+specifies that a proxy can decide which future versions of this
+License can be used, that proxy's public statement of acceptance of a
+version permanently authorizes you to choose that version for the
+Document.
+
+11. RELICENSING
+
+"Massive Multiauthor Collaboration Site" (or "MMC Site") means any
+World Wide Web server that publishes copyrightable works and also
+provides prominent facilities for anybody to edit those works.  A
+public wiki that anybody can edit is an example of such a server.  A
+"Massive Multiauthor Collaboration" (or "MMC") contained in the site
+means any set of copyrightable works thus published on the MMC site.
+
+"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
+license published by Creative Commons Corporation, a not-for-profit
+corporation with a principal place of business in San Francisco,
+California, as well as future copyleft versions of that license
+published by that same organization.
+
+"Incorporate" means to publish or republish a Document, in whole or in
+part, as part of another Document.
+
+An MMC is "eligible for relicensing" if it is licensed under this
+License, and if all works that were first published under this License
+somewhere other than this MMC, and subsequently incorporated in whole or
+in part into the MMC, (1) had no cover texts or invariant sections, and
+(2) were thus incorporated prior to November 1, 2008.
+
+The operator of an MMC Site may republish an MMC contained in the site
+under CC-BY-SA on the same site at any time before August 1, 2009,
+provided the MMC is eligible for relicensing.
+
+
+ADDENDUM: How to use this License for your documents
+
+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and
+license notices just after the title page:
+
+    Copyright (c)  YEAR  YOUR NAME.
+    Permission is granted to copy, distribute and/or modify this document
+    under the terms of the GNU Free Documentation License, Version 1.3
+    or any later version published by the Free Software Foundation;
+    with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+    A copy of the license is included in the section entitled "GNU
+    Free Documentation License".
+
+If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
+replace the "with...Texts." line with this:
+
+    with the Invariant Sections being LIST THEIR TITLES, with the
+    Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
+
+If you have Invariant Sections without Cover Texts, or some other
+combination of the three, merge those two alternatives to suit the
+situation.
+
+If your document contains nontrivial examples of program code, we
+recommend releasing these examples in parallel under your choice of
+free software license, such as the GNU General Public License,
+to permit their use in free software.
diff --git a/LICENSES/GPL-3.0-or-later.txt b/LICENSES/GPL-3.0-or-later.txt
new file mode 100644
index 0000000..f288702
--- /dev/null
+++ b/LICENSES/GPL-3.0-or-later.txt
@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
+
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
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+                     END OF TERMS AND CONDITIONS
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+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/LICENSES/Unlicense.txt b/LICENSES/Unlicense.txt
new file mode 100644
index 0000000..68a49da
--- /dev/null
+++ b/LICENSES/Unlicense.txt
@@ -0,0 +1,24 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <http://unlicense.org/>
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..f136822
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,94 @@
+# lali (Lali Another Lisp Implementation)
+#
+# Author: Daniel Cerqueira (dan.git@lispclub.com)
+# Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+# Version: 0.0
+# Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+#           computer programming language
+# Homepage: https://gitlab.com/alexandre1985/lali
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Copyright (C) 2025 Daniel Cerqueira
+#
+# This file is part of lali.
+#
+# lali is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 3 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, see <https://www.gnu.org/licenses/>.
+#
+#
+# lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/> version
+# from 2016, written by Matthias Pirstitz, which is released to public domain
+# under Unlicense <https://unlicense.org/>.
+
+
+PROGRAM := lali
+LIBOBJECTS := liblali.o
+LIB := lib$(PROGRAM).a
+OBJECTS := $(LIBOBJECTS) lali.o
+HTML := README.html
+
+ifeq ($(shell uname -s), Linux)
+CPPFLAGS += -D_DEFAULT_SOURCE -D_BSD_SOURCE
+endif
+
+CFLAGS += -std=c11 -Wall -pedantic
+
+PREFIX ?= /usr/local
+
+.PHONY: native
+native: CPPFLAGS += -DNDEBUG
+native: CFLAGS   += -march=native -O2
+native: $(PROGRAM)
+
+.PHONY: generic
+generic: CPPFLAGS += -DNDEBUG
+generic: CFLAGS   += -mtune=generic -O2
+generic: $(PROGRAM)
+
+.PHONY: all
+all: CPPFLAGS += -DNDEBUG
+all: CFLAGS   += -march=native -O2
+all: $(PROGRAM) $(LIB) $(HTML)
+
+.PHONY: debug
+debug: CPPFLAGS += -DDEBUG
+debug: CFLAGS   += -g
+debug: LDFLAGS  += -g
+debug: $(PROGRAM)
+
+.PHONY: clean
+clean:
+	$(RM) $(PROGRAM) $(OBJECTS) $(LIB) $(HTML)
+
+.PHONY: lib
+lib: $(LIB)
+
+$(LIB): $(LIBOBJECTS)
+	$(AR) rc $@ $(LIBOBJECTS)
+	ranlib $@
+
+$(PROGRAM): $(OBJECTS)
+	$(CC) $(LDFLAGS) $(OBJECTS) -o $@
+# $(CC) $(LDFLAGS) lali.o -L. -l$(PROGRAM) -o $@
+
+%.o: %.c %.h
+	$(CC) $(CFLAGS) $(CPPFLAGS)  -c -o $@ $<
+
+.PHONY: html
+html: $(HTML)
+
+%.html: %.md
+	md2html -f -o $@ $<
+
+.PHONY: install
+install: native
+	install -D -m 311 -t $(PREFIX)/bin $(PROGRAM)
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d193110
--- /dev/null
+++ b/README.md
@@ -0,0 +1,377 @@
+<!--
+lali (Lali Another Lisp Implementation)
+
+Author: Daniel Cerqueira (dan.git@lispclub.com)
+Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+Version: 0.0
+Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+          computer programming language
+Homepage: https://gitlab.com/alexandre1985/lali
+SPDX-License-Identifier: GFDL-1.3-or-later
+
+Copyright (C) 2025 Daniel Cerqueira
+
+This file is part of lali.
+
+Permission is granted to copy, distribute and/or modify this document under the
+terms of the GNU Free Documentation License, Version 1.3 or any later version
+published by the Free Software Foundation; with no Invariant Sections, no
+Front-Cover Texts, and no Back-Cover Texts.
+
+You should have received a copy of the GNU Free Documentation License along with
+this program; if not, see <https://www.gnu.org/licenses/>.
+
+
+lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/> version
+from 2016, written by Matthias Pirstitz, which is released to public domain under
+Unlicense <https://unlicense.org/>.
+-->
+
+# lali (Lali Another Lisp Implementation)
+
+lali is a small implementation of LISP, derived from tiny-lisp, written in
+standard C11. It has features such as macros, tail recursion and a copying garbage
+collector.
+
+lali extends and improves the original LISP. It tries to stay connected to the
+roots, while been greatly powerful. Also, aims at bringing joy to the programmer's
+mind. What you write, becomes part of who you are.
+
+
+## Language features
+
+* read-eval-print loop
+* interpretation from stdin or file arguments
+* numbers, strings, symbols and lists
+* functions and macros
+* lexical scoping
+* scheme-style dotted parameter lists
+* scheme-style tail recursion
+* copying garbage collector
+
+### Numeric operations
+
+lali supports the five arithmetic operations `+`, `-`, `*`, `/`, `%` (with `%` the
+operands are automatically converted to integer) as well as the relational
+operations `!` (different), `<`, `>`:
+
+    (- 5)                        ; -5
+    (- 5 3.2 .6)                 ; 1.2
+    (< 2 4 6.8)                  ; t
+    (> 4 8)                      ; f
+    (! 4 4)                      ; f
+
+#### Random number operation
+
+`(random [number])` takes no or one number argument, returns a random number below
+`number` until 0.
+
+    (random)                     ; 2.1442e+09
+    (random 2)                   ; returns 0 or 1
+
+### Processing operations
+
+`(quote x)`, or `'x`, returns an expression without being processed:
+
+    (quote a)                    ; a
+    'b                           ; b
+    (quote  (a b c))             ; (a b c)
+    '(a b c)                     ; (a b c)
+
+`(say x)`, or `\x`, returns an expression without being processed, and with the
+first `car` as `()`. This result is useful when processing a list and wanting to
+do something at the beginning, because other cons cells should never have `()` in
+`car`:
+
+    (say a)                      ; (() . a)
+    \b                           ; (() . b)
+    (say (a b c))                ; (() a b c)
+    \(a b c)                     ; (() a b c)
+
+### List operations
+
+`(list ...)` returns a list containing the supplied arguments:
+
+    (list)                       ; ()
+    (list 1 2 3)                 ; (1 2 3)
+    (list 1 2 (+ 1 2))           ; (1 2 3)
+
+`(cons x y)` creates a new cons cell, the `car` of which is `x` and the `cdr` of
+which is `y`:
+
+    (cons 1 2)                   ; (1 . 2)
+    (cons 1 '(2))                ; (1 2)
+
+`(car x)`, `(cdr x)` return the `car` and `cdr` of a list respectively:
+
+    (car '(1 2 3))               ; 1
+    (cdr '(1 2 3))               ; (2 3)
+
+### Predicates
+
+`(dif x y)` returns `t` if `x` and `y` refers to different objects, or if they are
+numbers with different values, or if they are string objects with different
+contents:
+
+    (dif 1 1)                    ; f
+    (dif 1 2)                    ; t
+    (dif 'a 'a)                  ; f
+    (dif 'a 'b)                  ; t
+    (dif t t)                    ; f
+    (dif t f)                    ; t
+    (dif '(1 2) '(1 2))          ; t
+
+`(differ x y)` returns `t` if `x` and `y` are objects of different structure and
+each of their elements satisfy the `dif` predicate, otherwise `f`:
+
+    (differ '(1 2) '(1))         ; t
+    (differ '(1 2) '(1 2))       ; f
+
+`(space x)` returns `t` if `x` is an empty list `()`, otherwise `f`:
+
+    (space ())                   ; t
+    (space 1)                    ; f
+    (space t)                    ; f
+    (space '(1 2))               ; f
+
+`(ap x)` returns `t` if `x` is "an existing thing" (not an empty list `()`),
+otherwise `f`:
+
+    (ap ())                      ; f
+    (ap 1)                       ; t
+    (ap t)                       ; t
+    (ap '(1 2))                  ; t
+
+`(atom x)` returns `t` if `x` is an atom (and not an empty list `()`), otherwise
+`f`:
+
+    (atom ())                    ; f
+    (atom 1)                     ; t
+    (atom t)                     ; t
+    (atom '(1 2))                ; f
+
+`(listp x)` returns `t` if `x` is either an empty list `()`, or a list with
+atom(s), otherwise `f`:
+
+    (listp ())                   ; t
+    (listp 1)                    ; f
+    (listp t)                    ; f
+    (listp '(1 2))               ; t
+
+`(consp x)` returns `t` if `x` is a list with atom(s), otherwise `f`:
+
+    (consp ())                   ; f
+    (consp 1)                    ; f
+    (consp t)                    ; f
+    (consp '(1 2))               ; t
+
+`(zerop x)` returns `t` if `x` is the number zero, otherwise `f`:
+
+    (zerop 0)                    ; t
+    (zerop 1)                    ; f
+    (zerop t)                    ; error: t is not a number
+
+### Logical operations
+
+`(not x)` returns `t` if `x` is `f`, return `n` if `x` is `n`, otherwise returns
+`f`.
+
+`(and ...)` evaluates its arguments one at a time from left to right. As soon as
+any argument evaluates to `f`, `and` returns `f` without evaluating the remaining
+arguments. Otherwise, it returns the value produced by evaluating its last
+argument. If no arguments are supplied, `and` returns `t`:
+
+    (and)                        ; t
+    (and 1 2 3)                  ; 3
+    (and 1 f 3)                  ; f
+
+`(or ...)` evaluates its arguments one at a time from left to right. As soon as
+any argument does not evaluate to `f`, `or` returns its value without evaluating
+the remaining arguments. Otherwise, it returns `f`:
+
+    (or)                         ; f
+    (or 1 2 3)                   ; 1
+    (or f f 3)                   ; 3
+
+### Conditionals
+
+`(cond ...)` takes zero or more clauses, each of the form `(test [expr...])`.
+`cond` returns the result of evaluating `expr...` of the first clause for which
+`test` does not evaluate to `f` without evaluating the remaining clauses. If a
+clause does not supply `expr...`, the result of evaluating `test` is returned
+instead. If every `test` evaluates to `f`, or no clauses are given, `cond` returns
+`n`:
+
+    (cond)                       ; n
+    (cond (f 'Hello)
+          (t 'World))            ; World
+    (cond (f 'Hello)
+          ('World))              ; World
+    (cond (t 'Hello)
+          ('World))              ; Hello
+
+`(fill ...)` is similar to `cond`. But `fill` differs in its evaluation of `test`.
+When `test` does evaluate to `f` returns the result of evaluating `expr...`
+without evaluating the remaining clauses:
+
+    (fill)                       ; n
+    (fill (f 'Hello)
+          (t 'World))            ; Hello
+    (fill (f 'Hello)
+          ('World))              ; Hello
+    (fill (t 'Hello)
+          ('World))              ; World
+
+### Grouping functions
+
+`(prog ...)` takes zero or more expressions, and evaluates each expression, one
+after the other. Returns the evaluation of the last expression. Returns `n`, if no
+expression is given:
+
+    (prog)                       ; n
+    (prog 'Hello
+           (atom f))             ; t
+    (prog 'Hello
+           n
+           (car 'World))         ; error: World is not a list
+
+`(progs expr ...)` is similar to `prog`. But `progs` differs when the evaluation
+of any expression is equal to the symbol of the evaluation of `expr`, stopping
+evaluation of further expressions and returning the symbol of the evaluation of
+`expr` immediately:
+
+    (progs n)                    ; n
+    (progs n
+           'Hello
+           (atom f))             ; t
+    (progs n
+           'Hello
+           n
+           (car 'World))         ; n
+
+### Defining variables
+
+`(set expr-var-A expr-val-A ...)` binds the result of evaluating `expr-val-A` to
+the symbol of `expr-var-A` evaluated. More than one `expr-var`-`expr-val` pair can
+be given. `set` returns the value bound to the last symbol:
+
+    (set 'a 1
+         'b 2)                   ; 2
+    a                            ; 1
+    b                            ; 2
+
+### Defining functions
+
+`(lambda params expr...)` creates an anonymous function with parameters `params`
+and body `expr...`. `params` can be `()`, a symbol, or a list of symbols. If
+`params` is a symbol or a dotted list of symbols, the function will accept a
+variable number of arguments:
+
+    ((lambda ()
+       'Hello))                  ; Hello
+    ((lambda (a b)
+       (+ a b)) 1 2)             ; 3
+    ((lambda (a b . c)
+       c) 1 2 3 4 5)             ; (3 4 5)
+    ((lambda args
+       args) 1 2 3 4 5)          ; (1 2 3 4 5)
+
+`(defun name params expr...)` creates a function and binds it to the symbol
+`name`:
+
+    (defun plus1 (x)
+      (+ x 1))                   ; #<Lambda (x)>
+    (plus1 2)                    ; 3
+
+### Defining macros
+
+`(macro params expr...)` creates an anonymous macro with parameters `params` and
+body `expr...`.
+
+`(defmacro name params expr...)` creates a macro and binds it to the symbol
+`name`.
+
+Macros are different from functions in that they do not evaluate their arguments
+when called. Instead, we can think of them as taking expressions as input and
+returning a new expression as output.
+
+Imagine we want to implement `(when test expr...)`:
+
+    (set 'x '(1 2 3))            ; (1 2 3)
+    (when (consp x)
+          (car x))               ; 1
+    (set 'x 'hello)
+    (when (consp x)
+          (car x))               ; n
+
+`when`, if implemented as a function, would not work correctly, since `expr...`
+would be evaluated as soon as `when` is called:
+
+    (set 'x 'Hello)
+    (when (consp x)
+          (car x))               ; error: Hello is not a list
+
+However, we can implement `when` as a macro that wraps `expr...` in a call to
+`if`:
+
+    (defmacro when (test . expr)
+      (list cond (list test (cons 'prog expr))))
+
+`(when (consp x) (car x))` would then produce the expression
+`(cond ((consp x) (prog (car x))))` which yields the expected behaviour.
+
+### Input operation
+
+`(read)` takes zero arguments, and reads an expression from standard input:
+
+    (set 'a (read))              ; type (Hello World!) followed by an enter
+    a                            ; (Hello World!)
+
+### Eval operation
+
+`(eval expr)` takes one expression, and evaluates `expr`:
+
+    (eval t)                     ; t
+    (prog
+      (set 'a 'b)
+      (eval a))                  ; error: b has no value
+    (prog
+      (set 'a 'b)
+      (eval 'a))                 ; b
+    (eval '(atom 1))             ; t
+    (eval '(run it))             ; error: run has no value
+    (prog
+      (set 'a 'b)
+      (eval '(a it)))            ; error: b is not a function
+
+### Output operations
+
+`(newline)` prints a newline to the standard output.
+
+`(print x)` prints `x` to the standard output, exactly the way it was entered:
+
+    (print '(Hello World!))      ; prints (Hello World!) followed by a space
+
+`(princ x)` is similar to `print`. But `princ` differs in its handling of lists
+outputting them without the initial/ending parenthesis:
+
+    (princ '(Hello World!))      ; prints Hello World! followed by a space
+
+### Time operation
+
+`(time)` gives a timestamp in (sec minute hour day month year dow dst utcoff).
+
+    (time)                       ; (23 54 17 13 5 2025 2 t 3600)
+
+## Copyright
+
+You can find the licenses of lali in the LICENSES/ directory.
+
+lali uses year ranges in its copyright text. For example, the year range
+"2025-2027" means years "2025, 2026, and 2027".
+
+
+## Contributions
+
+If you want to contribute, please send me (git) patches over email. My address is
+at the source's copyright notices. Thank you!
diff --git a/TAGS b/TAGS
new file mode 100644
index 0000000..59105de
--- /dev/null
+++ b/TAGS
@@ -0,0 +1,106 @@
+
+lali.c,85
+#define YEARS 37,1298
+void runFile(41,1416
+void runREPL(59,1816
+int main(87,2375
+
+liblali.c,3583
+#define MEMORY_SIZE 37,1298
+static Memory *memory memory
39,1338
+Object *symbols symbols
41,1389
+Object *nil nil
42,1413
+Object *n n
43,1469
+Object *t t
44,1522
+Object *f f
45,1575
+static unsigned int seed 47,1629
+jmp_buf exceptionEnv;49,1660
+void exceptionWithObject(54,1765
+Object *gcMoveObject(gcMoveObject
114,4107
+void gc(136,4806
+size_t memoryAlign(183,6199
+Object *memoryAllocObject(memoryAllocObject
187,6306
+Object *newObject(newObject
216,7294
+Object *newObjectFrom(newObjectFrom
220,7399
+Object *newNumber(newNumber
226,7586
+Object *newObjectWithString(newObjectWithString
232,7731
+Object *newStringWithLength(newStringWithLength
239,7974
+Object *newString(newString
267,8904
+Object *newCons(newCons
271,9015
+Object *newSymbolWithLength(newSymbolWithLength
278,9186
+Object *newSymbol(newSymbol
293,9696
+Object *newObjectWithClosure(newObjectWithClosure
297,9807
+Object *newLambda(newLambda
318,10483
+Object *newMacro(newMacro
322,10635
+Object *newPrimitive(newPrimitive
326,10785
+Object *newEnv(newEnv
333,10977
+int streamGetc(372,12345
+Stream *streamSeek(streamSeek
440,14380
+int streamPeek(448,14557
+int readNext(457,14763
+int initialReadNext(468,14980
+int peekForward(479,15217
+int peekNext(486,15393
+int readWhile(490,15464
+Object *readUnary(readUnary
499,15640
+Object *readString(readString
512,16017
+int isSymbolChar(528,16547
+Object *readNumberOrSymbol(readNumberOrSymbol
533,16672
+Object *reverseList(reverseList
565,17640
+Object *readList(readList
578,17840
+Object *readExpr(readExpr
610,18830
+void writeObject(633,19549
+#define CASE(635,19637
+#undef CASE642,19948
+#define CASE(678,20949
+#undef CASE687,21348
+Object *envLookup(envLookup
713,22169
+Object *envAdd(envAdd
728,22526
+Object *envSet(envSet
738,22829
+Object *primitiveSpace(primitiveSpace
760,23413
+Object *primitiveAtom(primitiveAtom
764,23506
+Object *primitiveDif(primitiveDif
782,24090
+Object *primitiveCar(primitiveCar
793,24495
+Object *primitiveCdr(primitiveCdr
804,24731
+Object *primitiveCons(primitiveCons
815,24967
+Object *primitivePrint(primitivePrint
822,25143
+Object *primitivePrinc(primitivePrinc
828,25284
+Object *primitiveNewline(primitiveNewline
834,25426
+Object *primitiveRead(primitiveRead
839,25516
+Object *primitiveTime(primitiveTime
850,25762
+Object *primitiveRandom(primitiveRandom
877,26414
+#define DEFINE_PRIMITIVE_ARITHMETIC(890,26794
+DEFINE_PRIMITIVE_ARITHMETIC(920,28871
+#define DEFINE_PRIMITIVE_RELATIONAL(926,29182
+typedef struct Primitive 954,30979
+  char *name;name
955,31006
+  int nMinArgs,956,31020
+  int nMinArgs, nMaxArgs;956,31020
+  Object *(* eval)957,31046
+} Primitive;958,31091
+Primitive primitives[primitives
960,31105
+  PRIMITIVE_EVAL,1000,32893
+  PRIMITIVE_QUOTE,1001,32911
+  PRIMITIVE_SAY,1002,32930
+  PRIMITIVE_SET,1003,32947
+  PRIMITIVE_PROG,1004,32964
+  PRIMITIVE_PROGS,1005,32982
+  PRIMITIVE_COND,1007,33023
+  PRIMITIVE_FILL,1008,33041
+  PRIMITIVE_LAMBDA,1009,33059
+  PRIMITIVE_MACRO1010,33079
+Object *evalSet(evalSet
1021,33432
+Object *evalProg(evalProg
1047,34162
+Object *progs1(progs1
1067,34584
+Object *evalProgs(evalProgs
1093,35277
+Object *evalCond(evalCond
1119,36027
+Object *evalFill(evalFill
1142,36609
+Object *evalLambda(evalLambda
1165,37191
+Object *evalMacro(evalMacro
1172,37378
+Object *expandMacro(expandMacro
1179,37563
+Object *expandMacroTo(expandMacroTo
1189,37845
+Object *evalList(evalList
1203,38235
+Object *evalExpr(evalExpr
1217,38607
+#define LISP(1293,41772
+static char *stdlib stdlib
1295,41804
+Object *newRootEnv(newRootEnv
1351,43430
diff --git a/THANKS b/THANKS
new file mode 100644
index 0000000..2019932
--- /dev/null
+++ b/THANKS
@@ -0,0 +1,5 @@
+This project is based on tiny-lisp, originally written by Matthias Pirstitz.
+Modified and designed by Daniel Cerqueira. Other people also contributed. Here is
+a list of those people:
+
+alexlehm
diff --git a/TODO b/TODO
new file mode 100644
index 0000000..0a55ffd
--- /dev/null
+++ b/TODO
@@ -0,0 +1,38 @@
+maybe make the repl use the readline library.
+create lisp code for addition.
+use secure functions.
+make quest a thing.
+remove macros?
+
+split, join.
+make unit testing.
+instead of returning "#<Lambda ..." it should return the expression.
+remove lambda_type and macro_type.
+
+
+fix a security bug of setting a primitive. (done)
+improve performance of progs1. (done)
+makes no sense to make progs accept a lambda argument. (because the evaluation of each step would require a fixing a symbol, such as fixing the symbol "t").
+add \b interpretation. (done)
+improve performance of evalProg. (done)
+(random n). (done)
+add math operator %. (done)
+make time. (done)
+makes no sense to remove numbers altogether, because symbols won't be neutral (as with previous badly thought plans).
+make list structure begin with an cell which has a "special" symbol in car (still don't know which symbol might be). then make a C predicate function to detect if the car is the beginning of a list (the end already is marked by a cdr of ()). (done)
+change from label to set. (done)
+makefile with lib. (done)
+update documentation. (done)
+makes no sense to remove strings altogether. (because of " ", "(", ")", or ".")
+create progs, a prog that stops if expr evaluates to n. (done)
+rename progn to prog. (done)
+make read function. (done)
+make princ functions not print the parentesis of a list. (done)
+support scripting with a shebang. (done)
+receive input from stdin. (done)
+make load code of argument files. (done)
+remove <= , >= and = . add !. (done)
+expose eval as a function. (done)
+add dif. remove eq. (done)
+add fill. (done)
+add n. (done)
diff --git a/examples/hanoi.lali b/examples/hanoi.lali
new file mode 100644
index 0000000..cf82382
--- /dev/null
+++ b/examples/hanoi.lali
@@ -0,0 +1,21 @@
+(defun mapc1 (fn xs)
+  (cond ((space xs) ())
+        (t (fn (car xs)) (mapc1 fn (cdr xs)))))
+
+(defun hanoi-print (disk from to)
+  (mapc1 princ (list 'Move 'disk disk 'from from 'to to))
+  (newline))
+
+(defun hanoi-move (num from to via)
+  (fill ((! num 1)
+         (hanoi-print num from to))
+        (f
+         (prog
+           (hanoi-move (- num 1) from via to)
+           (hanoi-print num from to)
+           (hanoi-move (- num 1) via to from)))))
+
+(defun hanoi (num)
+  (hanoi-move num 'L 'M 'R))
+
+(hanoi 3)
diff --git a/examples/mandelbrot.lali b/examples/mandelbrot.lali
new file mode 100644
index 0000000..d546f4f
--- /dev/null
+++ b/examples/mandelbrot.lali
@@ -0,0 +1,30 @@
+(defun for (from to func)
+  (cond ((< from to) (func from) (for (+ from 1) to func))))
+
+(set 'mandelbrot-chars
+  (list " " "." "," "`" "'" "\"" ":" ";" "-" "+" "o" "O" "0" "1"
+        "2" "3" "4" "5" "6" "7" "8" "9" "%" "*" "&" "$" "@" "#"))
+
+(defun mandelbrot-iter (x y x0 y0 i)
+  (fill ((! i 28) " ")
+        ((not (> (+ (* x0 x0) (* y0 y0)) 4)) (nth i mandelbrot-chars))
+        (f (mandelbrot-iter x y
+                            (+ (- (* x0 x0) (* y0 y0)) x) (+ (* 2 x0 y0) y)
+                            (+ i 1)))))
+
+(defun mandelbrot-char (x y)
+  (mandelbrot-iter x y
+                   (+ (- (* x x) (* y y)) x) (+ (* 2 x y) y)
+                   0))
+
+(defun mandelbrot (xmin xmax ymin ymax)
+  (for 0 24 (lambda (py)
+    (for 0 80 (lambda (px)
+      (princ
+        (mandelbrot-char
+          (+ (* (/ px 80) (- xmax xmin)) xmin)
+          (+ (* (/ py 24) (- ymax ymin)) ymin)))))
+    (newline))))
+
+(mandelbrot -2.15 1.25 -1.25 1.25)
+; (mandelbrot -1.5 -1.1 -0.2 0.1)
diff --git a/lali.c b/lali.c
new file mode 100644
index 0000000..15e90a2
--- /dev/null
+++ b/lali.c
@@ -0,0 +1,160 @@
+/*
+ * lali (Lali Another Lisp Implementation)
+ *
+ * Author: Daniel Cerqueira (dan.git@lispclub.com)
+ * Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+ * Version: 0.0
+ * Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+ *           computer programming language
+ * Homepage: https://gitlab.com/alexandre1985/lali
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Copyright (C) 2025 Daniel Cerqueira
+ *
+ * This file is part of lali.
+ *
+ * lali is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, see <https://www.gnu.org/licenses/>.
+ *
+ *
+ * lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/>
+ * version from 2016, written by Matthias Pirstitz, which is released to public
+ * domain under Unlicense <https://unlicense.org/>.
+ */
+
+
+#include "liblali.h"
+
+#define YEARS                "2025"
+
+// MAIN ///////////////////////////////////////////////////////////////////////
+
+void runFile(int infd, Object **env, GC_PARAM) {
+  Stream stream = { STREAM_TYPE_FILE, .fd = infd };
+  GC_TRACE(gcObject, nil);
+
+  if (setjmp(exceptionEnv))
+    return;
+
+  // deal with shebang
+  if (peekForward(&stream, true) == EOF)
+    return;
+
+  do {
+    *gcObject = nil;
+    *gcObject = readExpr(&stream, GC_ROOTS);
+    evalExpr(gcObject, env, GC_ROOTS);
+  } while (peekNext(&stream) != EOF);
+}
+
+void runREPL(int infd, Object **env, GC_PARAM) {
+  Stream stream = { STREAM_TYPE_FILE, .fd = infd };
+  GC_TRACE(gcObject, nil);
+
+  for (;;) {
+    if (setjmp(exceptionEnv))
+      continue;
+
+    for (;;) {
+      *gcObject = nil;
+
+      fputs("lali> ", stdout);
+      fflush(stdout);
+
+      if (peekNext(&stream) == EOF) {
+        fputc('\n', stdout);
+        return;
+      }
+
+      *gcObject = readExpr(&stream, GC_ROOTS);
+      *gcObject = evalExpr(gcObject, env, GC_ROOTS);
+
+      writeObject(*gcObject, true, stdout);
+      fputc('\n', stdout);
+    }
+  }
+}
+
+int main(int argc, char *argv[]) {
+  int options = 0;
+  bool repl = false;
+  bool close = false;
+  bool quiet = false;
+
+  if (argc >= 2) {
+    if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
+      fprintf(stderr, "basic usages:\nnormal:        %s [file]...\nclose stdin:   %s -c [file]...\nrun repl:      %s -r [-q] [file]...\n\nin normal mode, reads from standard input.\nwhen present, load file(s) at startup. can be used as library file(s).\n", argv[0], argv[0], argv[0]);
+      return EXIT_SUCCESS;
+    } else if (!strcmp(argv[1], "-c")) {
+      options++;
+      close = true;
+    } else if (!strcmp(argv[1], "-r")) {
+      options++;
+      repl = true;
+      if (argc > 2 && !strcmp(argv[2], "-q")) {
+        options++;
+        quiet = true;
+      }
+    } else if (!strcmp(argv[1], "-q")) {
+      options++;
+      quiet = true;
+      if (argc > 2 && !strcmp(argv[2], "-r")) {
+        options++;
+        repl = true;
+      }
+    } else if (argv[1][0] == '-') {
+      fprintf(stderr, "%s: unrecognized option, `%s'\n", argv[0], argv[1]);
+      return EXIT_FAILURE;
+    }
+  }
+
+  GC_PARAM = nil;
+
+  if (setjmp(exceptionEnv))
+    return EXIT_FAILURE;
+
+  symbols = nil;
+  symbols = newCons(&nil, &symbols, GC_ROOTS);
+  symbols = newCons(&n, &symbols, GC_ROOTS);
+  symbols = newCons(&t, &symbols, GC_ROOTS);
+  symbols = newCons(&f, &symbols, GC_ROOTS);
+
+  GC_TRACE(gcEnv, newRootEnv(GC_ROOTS));
+
+  int fd = 0;
+
+  if (argc > 1) {
+    for (int i = ++options; i < argc; i++) {
+      if ((fd = open(argv[i], O_RDONLY)) == -1) {
+        fprintf(stderr, "%s: open() failed, %s\n", argv[0], strerror(errno));
+        return EXIT_FAILURE;
+      }
+      runFile(fd, gcEnv, GC_ROOTS);
+    }
+  }
+
+  if (repl) {
+    if(!isatty(STDIN_FILENO)) {
+      fprintf(stderr, "%s: repl does not accept piping\n", argv[0]);
+      return EXIT_FAILURE;
+    }
+
+    if (!quiet)
+      fprintf(stdout, "lali Copyright (C) %s Daniel Cerqueira\n\nThis is free software: you are free to change and redistribute it,\nunder certain conditions.\nThis program comes with NO WARRANTY, to the extent permitted by law.\n", YEARS);
+
+    runREPL(STDIN_FILENO, gcEnv, GC_ROOTS);
+  }
+  else if (!close)
+    runFile(STDIN_FILENO, gcEnv, GC_ROOTS);
+
+  return EXIT_SUCCESS;
+}
diff --git a/liblali.c b/liblali.c
new file mode 100644
index 0000000..e2239dd
--- /dev/null
+++ b/liblali.c
@@ -0,0 +1,1404 @@
+/*
+ * lali (Lali Another Lisp Implementation)
+ *
+ * Author: Daniel Cerqueira (dan.git@lispclub.com)
+ * Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+ * Version: 0.0
+ * Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+ *           computer programming language
+ * Homepage: https://gitlab.com/alexandre1985/lali
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Copyright (C) 2025 Daniel Cerqueira
+ *
+ * This file is part of lali.
+ *
+ * lali is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, see <https://www.gnu.org/licenses/>.
+ *
+ *
+ * lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/>
+ * version from 2016, written by Matthias Pirstitz, which is released to public
+ * domain under Unlicense <https://unlicense.org/>.
+ */
+
+
+#include "liblali.h"
+
+#define MEMORY_SIZE          3000000UL
+
+static Memory *memory = &(Memory){ MEMORY_SIZE };
+
+Object *symbols = NULL;
+Object *nil = &(Object){ TYPE_SYMBOL, .string = "()" };
+Object *n = &(Object){ TYPE_SYMBOL, .string = "n" };
+Object *t = &(Object){ TYPE_SYMBOL, .string = "t" };
+Object *f = &(Object){ TYPE_SYMBOL, .string = "f" };
+
+static unsigned int seed = 1;
+
+jmp_buf exceptionEnv;
+
+
+// EXCEPTION HANDLING /////////////////////////////////////////////////////////
+
+void exceptionWithObject(Object *object, char *format, ...) {
+  fputs("error: ", stderr);
+
+  if (object) {
+    writeObject(object, true, stderr);
+    fputc(' ', stderr);
+  }
+
+  va_list args;
+  va_start(args, format);
+  vfprintf(stderr, format, args);
+  va_end(args);
+  fputc('\n', stderr);
+
+  longjmp(exceptionEnv, 1);
+}
+
+// GARBAGE COLLECTION /////////////////////////////////////////////////////////
+
+/* This implements Cheney's copying garbage collector, with which memory is
+ * divided into two equal halves (semispaces): from- and to-space. From-space
+ * is where new objects are allocated, whereas to-space is used during garbage
+ * collection.
+ *
+ * When garbage collection is performed, objects that are still in use (live)
+ * are copied from from-space to to-space. To-space then becomes the new
+ * from-space and vice versa, thereby discarding all objects that have not
+ * been copied.
+ *
+ * Our garbage collector takes as input a list of root objects. Objects that
+ * can be reached by recursively traversing this list are considered live and
+ * will be moved to to-space. When we move an object, we must also update its
+ * pointer within the list to point to the objects new location in memory.
+ *
+ * However, this implies that our interpreter cannot use raw pointers to
+ * objects in any function that might trigger garbage collection (or risk
+ * causing a SEGV when accessing an object that has been moved). Instead,
+ * objects must be added to the list and then only accessed through the
+ * pointer inside the list.
+ *
+ * Thus, whenever we would have used a raw pointer to an object, we use a
+ * pointer to the pointer inside the list instead:
+ *
+ *   function:              pointer to pointer inside list (Object **)
+ *                                  |
+ *                                  v
+ *   list of root objects:  pointer to object (Object *)
+ *                                  |
+ *                                  v
+ *   semispace:             object in memory
+ *
+ * GC_ROOTS and GC_PARAM are used to pass the list from function to function.
+ *
+ * GC_TRACE adds an object to the list and declares a variable which points to
+ * the objects pointer inside the list.
+ *
+ *   GC_TRACE(gcX, X):  add object X to the list and declare Object **gcX
+ *                      to point to the pointer to X inside the list.
+ */
+
+Object *gcMoveObject(Object *object) {
+  // skip object if it is not within from-space (i.e. on the stack)
+  if (object < (Object *)memory->fromSpace
+      || object >= (Object *)((char *)memory->fromSpace + memory->fromOffset))
+    return object;
+
+  // if the object has already been moved, return its new location
+  if (object->type == (Type)-1)
+    return object->forward;
+
+  // copy object to to-space
+  Object *forward = (Object *)((char *)memory->toSpace + memory->toOffset);
+  memcpy(forward, object, object->size);
+  memory->toOffset += object->size;
+
+  // mark object as moved and set forwarding pointer
+  object->type = (Type)-1;
+  object->forward = forward;
+
+  return object->forward;
+}
+
+void gc(GC_PARAM) {
+  memory->toOffset = 0;
+
+  // move symbols and root objects
+  symbols = gcMoveObject(symbols);
+
+  for (Object *object = GC_ROOTS; object != nil; object = object->cdr)
+    object->car = gcMoveObject(object->car);
+
+  // iterate over objects in to-space and move all objects they reference
+  for (Object *object = memory->toSpace;
+       object < (Object *)((char *)memory->toSpace + memory->toOffset);
+       object = (Object *)((char *)object + object->size)) {
+
+    switch (object->type) {
+    case TYPE_NUMBER:
+    case TYPE_STRING:
+    case TYPE_SYMBOL:
+    case TYPE_PRIMITIVE:
+      break;
+    case TYPE_CONS:
+      object->car = gcMoveObject(object->car);
+      object->cdr = gcMoveObject(object->cdr);
+      break;
+    case TYPE_LAMBDA:
+    case TYPE_MACRO:
+      object->params = gcMoveObject(object->params);
+      object->body = gcMoveObject(object->body);
+      object->env = gcMoveObject(object->env);
+      break;
+    case TYPE_ENV:
+      object->parent = gcMoveObject(object->parent);
+      object->vars = gcMoveObject(object->vars);
+      object->vals = gcMoveObject(object->vals);
+      break;
+    }
+  }
+
+  // swap from- and to-space
+  void *swap = memory->fromSpace;
+  memory->fromSpace = memory->toSpace;
+  memory->toSpace = swap;
+  memory->fromOffset = memory->toOffset;
+}
+
+// MEMORY MANAGEMENT //////////////////////////////////////////////////////////
+
+size_t memoryAlign(size_t size, size_t alignment) {
+  return (size + alignment - 1) & ~(alignment - 1);
+}
+
+Object *memoryAllocObject(Type type, size_t size, GC_PARAM) {
+  size = memoryAlign(size, sizeof (void *));
+
+  // allocate from- and to-space
+  if (!memory->fromSpace) {
+    if (!(memory->fromSpace = mmap(NULL, memory->capacity * 2,
+                                   PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)))
+      exception("mmap() failed, %s", strerror(errno));
+
+    memory->toSpace = (char *)memory->fromSpace + memory->capacity;
+  }
+
+  // run garbage collection if capacity exceeded
+  if (memory->fromOffset + size >= memory->capacity)
+    gc(GC_ROOTS);
+  if (memory->fromOffset + size >= memory->capacity)
+    exception("out of memory, %lu bytes", (unsigned long)size);
+
+  // allocate object in from-space
+  Object *object = (Object *)((char *)memory->fromSpace + memory->fromOffset);
+  object->type = type;
+  object->size = size;
+  memory->fromOffset += size;
+
+  return object;
+}
+
+// CONSTRUCTING OBJECTS ///////////////////////////////////////////////////////
+
+Object *newObject(Type type, GC_PARAM) {
+  return memoryAllocObject(type, sizeof (Object), GC_ROOTS);
+}
+
+Object *newObjectFrom(Object **from, GC_PARAM) {
+  Object *object = memoryAllocObject((*from)->type, (*from)->size, GC_ROOTS);
+  memcpy(object, *from, (*from)->size);
+  return object;
+}
+
+Object *newNumber(double number, GC_PARAM) {
+  Object *object = newObject(TYPE_NUMBER, GC_ROOTS);
+  object->number = number;
+  return object;
+}
+
+Object *newObjectWithString(Type type, size_t size, GC_PARAM) {
+  size = (size > sizeof (((Object *)NULL)->string))
+    ? size - sizeof (((Object *)NULL)->string)
+    : 0;
+  return memoryAllocObject(type, sizeof (Object) + size, GC_ROOTS);
+}
+
+Object *newStringWithLength(char *string, size_t length, GC_PARAM) {
+  int nEscapes = 0;
+
+  for (int i = 1; i < length; ++i)
+    if (string[i - 1] == '\\' && strchr("\\\"trn", string[i]))
+      ++i, ++nEscapes;
+
+  Object *object = newObjectWithString(TYPE_STRING,
+                                       length - nEscapes + 1, GC_ROOTS);
+
+  for (int r = 1, w = 0; r <= length; ++r) {
+    if (string[r - 1] == '\\' && r < length) {
+      switch (string[r]) {
+      case '\\': object->string[w++] = '\\'; r++; break;
+      case '"':  object->string[w++] = '"';  r++; break;
+      case 't':  object->string[w++] = '\t'; r++; break;
+      case 'r':  object->string[w++] = '\r'; r++; break;
+      case 'b':  object->string[w++] = '\b'; r++; break;
+      case 'n':  object->string[w++] = '\n'; r++; break;
+      default:   object->string[w++] = '\\';      break;
+      }
+    } else
+      object->string[w++] = string[r - 1];
+  }
+
+  object->string[length - nEscapes] = '\0';
+  return object;
+}
+
+Object *newString(char *string, GC_PARAM) {
+  return newStringWithLength(string, strlen(string), GC_ROOTS);
+}
+
+Object *newCons(Object **car, Object **cdr, GC_PARAM) {
+  Object *object = newObject(TYPE_CONS, GC_ROOTS);
+  object->car = *car;
+  object->cdr = *cdr;
+  return object;
+}
+
+Object *newSymbolWithLength(char *string, size_t length, GC_PARAM) {
+  for (Object *object = symbols; object != nil; object = object->cdr)
+    if (memcmp(object->car->string, string, length) == 0
+        && object->car->string[length] == '\0')
+      return object->car;
+
+  GC_TRACE(gcObject, newObjectWithString(TYPE_SYMBOL, length + 1, GC_ROOTS));
+  memcpy((*gcObject)->string, string, length);
+  (*gcObject)->string[length] = '\0';
+
+  symbols = newCons(gcObject, &symbols, GC_ROOTS);
+
+  return *gcObject;
+}
+
+Object *newSymbol(char *string, GC_PARAM) {
+  return newSymbolWithLength(string, strlen(string), GC_ROOTS);
+}
+
+Object *newObjectWithClosure(Type type, Object **params, Object **body, Object **env, GC_PARAM) {
+  Object *list;
+
+  for (list = *params; list->type == TYPE_CONS; list = list->cdr) {
+    if (list->car->type != TYPE_SYMBOL)
+      exceptionWithObject(list->car, "is not a symbol");
+    if (list->car == nil || list->car == n || list->car == t || list->car == f)
+      exceptionWithObject(list->car, "cannot be used as a parameter");
+  }
+
+  if (list != nil && list->type != TYPE_SYMBOL)
+    exceptionWithObject(list, "is not a symbol");
+
+  Object *object = newObject(type, GC_ROOTS);
+
+  object->params = *params;
+  object->body = *body;
+  object->env = *env;
+  return object;
+}
+
+Object *newLambda(Object **params, Object **body, Object **env, GC_PARAM) {
+  return newObjectWithClosure(TYPE_LAMBDA, params, body, env, GC_ROOTS);
+}
+
+Object *newMacro(Object **params, Object **body, Object **env, GC_PARAM) {
+  return newObjectWithClosure(TYPE_MACRO, params, body, env, GC_ROOTS);
+}
+
+Object *newPrimitive(int primitive, char *name, GC_PARAM) {
+  Object *object = newObject(TYPE_PRIMITIVE, GC_ROOTS);
+  object->primitive = primitive;
+  object->name = name;
+  return object;
+}
+
+Object *newEnv(Object **func, Object **vals, GC_PARAM) {
+  Object *object = newObject(TYPE_ENV, GC_ROOTS);
+
+  if ((*func) == nil)
+    object->parent = object->vars = object->vals = nil;
+  else {
+    Object *param = (*func)->params, *val = *vals;
+
+    for (int nArgs = 0;; param = param->cdr, val = val->cdr, ++nArgs) {
+      if (param == nil && val == nil)
+        break;
+      else if (param != nil && param->type == TYPE_SYMBOL)
+        break;
+      else if (val != nil && val->type != TYPE_CONS)
+        exceptionWithObject(val, "is not a list");
+      else if (param == nil && val != nil)
+        exceptionWithObject(*func, "expects at most %d arguments", nArgs);
+      else if (param != nil && val == nil) {
+        for (; param->type == TYPE_CONS; param = param->cdr, ++nArgs);
+        exceptionWithObject(*func, "expects at least %d arguments", nArgs);
+      }
+    }
+
+    object->parent = (*func)->env;
+    object->vars = (*func)->params;
+    object->vals = *vals;
+  }
+
+  return object;
+}
+
+// STREAM INPUT ///////////////////////////////////////////////////////////////
+
+/* The purpose of the stream functions is to provide an abstraction over file
+ * and string inputs. In order to accommodate the REPL, we need to be able to
+ * process character special files (such as stdin) character by character and
+ * evaluate expressions as they are being entered.
+ */
+
+int streamGetc(Stream *stream) {
+  if (stream->offset >= stream->length) {
+    switch (stream->type) {
+    case STREAM_TYPE_STRING:
+      // set length if a string was given but its length has not been set
+      if (!stream->length && stream->buffer && *stream->buffer) {
+        stream->length = strlen(stream->buffer);
+        return streamGetc(stream);
+      }
+
+      return EOF;
+
+    case STREAM_TYPE_FILE:
+      // if this is the first read, try to find the size of the file
+      if (!stream->buffer) {
+        struct stat st;
+
+        if (fstat(stream->fd, &st) == -1)
+          exception("fstat() failed, %s", strerror(errno));
+
+        if (S_ISREG(st.st_mode)) {
+          stream->size = st.st_size;
+
+          if (!(stream->buffer = malloc(stream->size)))
+            exception("out of memory, %ld bytes", (long)stream->size);
+
+          stream->capacity = stream->size;
+        } else
+          stream->size = -1;
+      }
+
+      // resize buffer to nearest multiple of BUFSIZ if capacity exceeded
+      if (stream->offset >= stream->capacity) {
+        char *buffer;
+        size_t capacity = stream->offset
+          ? (stream->offset / BUFSIZ + 1) * BUFSIZ
+          : BUFSIZ;
+
+        if (!(buffer = realloc(stream->buffer, capacity)))
+          exception("out of memory, %ld bytes", (long)capacity);
+
+        stream->buffer = buffer;
+        stream->capacity = capacity;
+      }
+
+      // read until offset reached
+      while (stream->length <= stream->offset) {
+        ssize_t nbytes = read(stream->fd, stream->buffer + stream->length,
+                              stream->capacity - stream->length);
+
+        if (nbytes > 0)
+          stream->length += nbytes;
+        else if (nbytes < 0 && errno != EINTR)
+          exception("read() failed, %s", strerror(errno));
+
+        if (nbytes == 0 || stream->length == stream->size) {
+          stream->type = STREAM_TYPE_STRING;
+          return streamGetc(stream);
+        }
+      }
+
+      break;
+    }
+  }
+
+  return (unsigned char)stream->buffer[stream->offset++];
+}
+
+Stream *streamSeek(Stream *stream, int offset) {
+  if (offset < 0 && -offset >= stream->offset)
+    stream->offset = 0;
+  else
+    stream->offset += offset;
+  return stream;
+}
+
+int streamPeek(Stream *stream) {
+  int ch = streamGetc(stream);
+  if (ch != EOF)
+    streamSeek(stream, -1);
+  return ch;
+}
+
+// READING S-EXPRESSIONS //////////////////////////////////////////////////////
+
+int readNext(Stream *stream) {
+  for (;;) {
+    int ch = streamGetc(stream);
+    if (ch == ';')
+      while ((ch = streamGetc(stream)) != EOF && ch != '\n');
+    if (isspace(ch))
+      continue;
+    return ch;
+  }
+}
+
+int initialReadNext(Stream *stream) {
+  for (;;) {
+    int ch = streamGetc(stream);
+    if (ch == ';' || ch == '#')
+      while ((ch = streamGetc(stream)) != EOF && ch != '\n');
+    if (isspace(ch))
+      continue;
+    return ch;
+  }
+}
+
+int peekForward(Stream *stream, bool shebang) {
+  int ch = (shebang) ? initialReadNext(stream) : readNext(stream);
+  if (ch != EOF)
+    streamSeek(stream, -1);
+  return ch;
+}
+
+int peekNext(Stream *stream) {
+  return peekForward(stream, false);
+}
+
+int readWhile(Stream *stream, int (*predicate)(int ch)) {
+  for (;;) {
+    int ch = streamPeek(stream);
+    if (!predicate(ch))
+      return ch;
+    streamGetc(stream);
+  }
+}
+
+Object *readUnary(Stream *stream, char *symbol, GC_PARAM) {
+  if (peekNext(stream) == EOF)
+    exception("unexpected end of stream in %s", symbol);
+
+  GC_TRACE(gcSymbol, newSymbol(symbol, GC_ROOTS));
+  GC_TRACE(gcObject, readExpr(stream, GC_ROOTS));
+
+  *gcObject = newCons(gcObject, &nil, GC_ROOTS);
+  *gcObject = newCons(gcSymbol, gcObject, GC_ROOTS);
+
+  return *gcObject;
+}
+
+Object *readString(Stream *stream, GC_PARAM) {
+  size_t offset = stream->offset;
+
+  for (bool isEscaped = false;;) {
+    int ch = streamGetc(stream);
+    if (ch == EOF)
+      exception("unexpected end of stream in string literal \"%.*s\"",
+                (int)(stream->offset - offset), stream->buffer + offset);
+    if (ch == '"' && !isEscaped)
+      return newStringWithLength(stream->buffer + offset,
+                                 stream->offset - offset - 1, GC_ROOTS);
+
+    isEscaped = (ch == '\\' && !isEscaped);
+  }
+}
+
+int isSymbolChar(int ch) {
+  static const char *valid = "!#$%&*+-./:<=>?@^_~";
+  return isalnum(ch) || strchr(valid, ch);
+}
+
+Object *readNumberOrSymbol(Stream *stream, GC_PARAM) {
+  size_t offset = stream->offset;
+  int ch = streamPeek(stream);
+
+  // skip optional leading sign
+  if (ch == '+' || ch == '-') {
+    streamGetc(stream);
+    ch = streamPeek(stream);
+  }
+
+  // try to read a number in integer or decimal format
+  if (ch == '.' || isdigit(ch)) {
+    if (isdigit(ch))
+      ch = readWhile(stream, isdigit);
+    if (!isSymbolChar(ch))
+      return newNumber(strtol(stream->buffer + offset, NULL, 10), GC_ROOTS);
+    if (ch == '.') {
+      ch = streamGetc(stream);
+      if (isdigit(streamPeek(stream))) {
+        ch = readWhile(stream, isdigit);
+        if (!isSymbolChar(ch))
+          return newNumber(strtod(stream->buffer + offset, NULL), GC_ROOTS);
+      }
+    }
+  }
+
+  // non-numeric character encountered, read a symbol
+  readWhile(stream, isSymbolChar);
+  return newSymbolWithLength(stream->buffer + offset,
+                             stream->offset - offset, GC_ROOTS);
+}
+
+Object *reverseList(Object *list) {
+  Object *object = nil;
+
+  while (list != nil) {
+    Object *swap = list;
+    list = list->cdr;
+    swap->cdr = object;
+    object = swap;
+  }
+
+  return object;
+}
+
+Object *readList(Stream *stream, GC_PARAM) {
+  GC_TRACE(gcList, nil);
+  GC_TRACE(gcLast, nil);
+
+  for (;;) {
+    int ch = readNext(stream);
+    if (ch == EOF)
+      exception("unexpected end of stream in list");
+    else if (ch == ')')
+      return reverseList(*gcList);
+    else if (ch == '.' && !isSymbolChar(streamPeek(stream))) {
+      if (*gcLast == nil)
+        exception("unexpected dot at start of list");
+      if ((ch = peekNext(stream)) == ')')
+        exception("expected object at end of dotted list");
+      if (!(*gcLast = readExpr(stream, GC_ROOTS)))
+        exception("unexpected end of stream in dotted list");
+      if ((ch = peekNext(stream)) != ')')
+        exception("unexpected object at end of dotted list");
+
+      readNext(stream);
+      Object *list = reverseList(*gcList);
+      (*gcList)->cdr = *gcLast;
+
+      return list;
+    } else {
+      *gcLast = readExpr(streamSeek(stream, -1), GC_ROOTS);
+      *gcList = newCons(gcLast, gcList, GC_ROOTS);
+    }
+  }
+}
+
+Object *readExpr(Stream *stream, GC_PARAM) {
+  for (;;) {
+    int ch = readNext(stream);
+    if (ch == EOF)
+      return NULL;
+    else if (ch == '\'')
+      return readUnary(stream, "quote", GC_ROOTS);
+    else if (ch == '\\')
+      return readUnary(stream, "say", GC_ROOTS);
+    else if (ch == '"')
+      return readString(stream, GC_ROOTS);
+    else if (ch == '(')
+      return readList(stream, GC_ROOTS);
+    else if (isSymbolChar(ch)
+             && (ch != '.' || isSymbolChar(streamPeek(stream))))
+      return readNumberOrSymbol(streamSeek(stream, -1), GC_ROOTS);
+    else
+      exception("unexpected character, `%c'", ch);
+  }
+}
+
+// WRITING OBJECTS ////////////////////////////////////////////////////////////
+
+void writeObject(Object *object, bool readably, FILE *file) {
+  switch (object->type) {
+#define CASE(type, ...)                         \
+    case type:                                  \
+      fprintf(file, __VA_ARGS__);               \
+      break
+    CASE(TYPE_NUMBER, "%g", object->number);
+    CASE(TYPE_SYMBOL, "%s", object->string);
+    CASE(TYPE_PRIMITIVE, "#<Primitive %s>", object->name);
+#undef CASE
+  case TYPE_STRING:
+    if (readably) {
+      fputc('"', file);
+      for (char *string = object->string; *string; ++string) {
+        switch (*string) {
+        case '"':  fputs("\\\"",  file); break;
+        case '\t': fputs("\\t",   file); break;
+        case '\r': fputs("\\r",   file); break;
+        case '\b': fputs("\\b",   file); break;
+        case '\n': fputs("\\n",   file); break;
+        case '\\': fputs("\\\\",  file); break;
+        default:   fputc(*string, file); break;
+        }
+      }
+      fputc('"', file);
+    } else
+      fprintf(file, "%s", object->string);
+    break;
+  case TYPE_CONS:
+    if (readably)
+      fputc('(', file);
+    writeObject(object->car, true, file);
+    while (object->cdr != nil) {
+      object = object->cdr;
+      if (object->type == TYPE_CONS) {
+        fputc(' ', file);
+        writeObject(object->car, true, file);
+      } else {
+        fputs(" . ", file);
+        writeObject(object, true, file);
+        break;
+      }
+    }
+    if (readably)
+      fputc(')', file);
+    break;
+#define CASE(type, name, object)                \
+    case type:                                  \
+      fprintf(file, "#<%s ", name);             \
+      writeObject(object, readably, file);      \
+      fprintf(file, ">");                       \
+      break
+    CASE(TYPE_LAMBDA, "Lambda", object->params);
+    CASE(TYPE_MACRO, "Macro", object->params);
+    CASE(TYPE_ENV, "Env", object->vars);
+#undef CASE
+  }
+}
+
+// ENVIRONMENT ////////////////////////////////////////////////////////////////
+
+/* An environment consists of a pointer to its parent environment (if any) and
+ * two parallel lists - vars and vals.
+ *
+ * Case 1 - vars is a regular list:
+ *   vars: (a b c), vals: (1 2 3)        ; a = 1, b = 2, c = 3
+ *
+ * Case 2 - vars is a dotted list:
+ *   vars: (a b . c), vals: (1 2)        ; a = 1, b = 2, c = nil
+ *   vars: (a b . c), vals: (1 2 3)      ; a = 1, b = 2, c = (3)
+ *   vars: (a b . c), vals: (1 2 3 4 5)  ; a = 1, b = 2, c = (3 4 5)
+ *
+ * Case 3 - vars is a symbol:
+ *   vars: a, vals: nil                  ; a = nil
+ *   vars: a, vals: (1)                  ; a = (1)
+ *   vars: a, vals: (1 2 3)              ; a = (1 2 3)
+ *
+ * Case 4 - vars and vals are both nil:
+ *   vars: nil, vals: nil
+ */
+
+Object *envLookup(Object *var, Object *env) {
+  for (; env != nil; env = env->parent) {
+    Object *vars = env->vars, *vals = env->vals;
+
+    for (; vars->type == TYPE_CONS; vars = vars->cdr, vals = vals->cdr)
+      if (vars->car == var)
+        return vals->car;
+
+    if (vars == var)
+      return vals;
+  }
+
+  exceptionWithObject(var, "has no value");
+}
+
+Object *envAdd(Object **var, Object **val, Object **env, GC_PARAM) {
+  GC_TRACE(gcVars, newCons(var, &nil, GC_ROOTS));
+  GC_TRACE(gcVals, newCons(val, &nil, GC_ROOTS));
+
+  (*gcVars)->cdr = (*env)->vars, (*env)->vars = *gcVars;
+  (*gcVals)->cdr = (*env)->vals, (*env)->vals = *gcVals;
+
+  return *val;
+}
+
+Object *envSet(Object **var, Object **val, Object **env, GC_PARAM) {
+  GC_TRACE(gcEnv, *env);
+
+  for (;;) {
+    Object *vars = (*gcEnv)->vars, *vals = (*gcEnv)->vals;
+
+    for (; vars->type == TYPE_CONS; vars = vars->cdr, vals = vals->cdr) {
+      if (vars->car == *var)
+        return vals->car = *val;
+      if (vars->cdr == *var)
+        return vals->cdr = *val;
+    }
+
+    if ((*gcEnv)->parent == nil)
+      return envAdd(var, val, gcEnv, GC_ROOTS);
+    else
+      *gcEnv = (*gcEnv)->parent;
+  }
+}
+
+// PRIMITIVES /////////////////////////////////////////////////////////////////
+
+Object *primitiveSpace(Object **args, GC_PARAM) {
+  return ((*args)->car == nil) ? t : f;
+}
+
+Object *primitiveAtom(Object **args, GC_PARAM) {
+  Object *first = (*args)->car;
+
+  return (first != nil && first->type != TYPE_CONS) ? t : f;
+}
+
+/* Object *primitiveEq(Object **args, GC_PARAM) {
+ *   Object *first = (*args)->car, *second = (*args)->cdr->car;
+ *
+ *   if (first->type == TYPE_NUMBER && second->type == TYPE_NUMBER)
+ *     return (first->number == second->number) ? t : f;
+ *   else if (first->type == TYPE_STRING && second->type == TYPE_STRING)
+ *     return !strcmp(first->string, second->string) ? t : f;
+ *   else
+ *     return (first == second) ? t : f;
+ * }
+ */
+
+Object *primitiveDif(Object **args, GC_PARAM) {
+  Object *first = (*args)->car, *second = (*args)->cdr->car;
+
+  if (first->type == TYPE_NUMBER && second->type == TYPE_NUMBER)
+    return (first->number != second->number) ? t : f;
+  else if (first->type == TYPE_STRING && second->type == TYPE_STRING)
+    return strcmp(first->string, second->string) ? t : f;
+  else
+    return (first != second) ? t : f;
+}
+
+Object *primitiveCar(Object **args, GC_PARAM) {
+  Object *first = (*args)->car;
+
+  if (first == nil)
+    return nil;
+  else if (first->type == TYPE_CONS)
+    return first->car;
+  else
+    exceptionWithObject(first, "is not a list");
+}
+
+Object *primitiveCdr(Object **args, GC_PARAM) {
+  Object *first = (*args)->car;
+
+  if (first == nil)
+    return nil;
+  else if (first->type == TYPE_CONS)
+    return first->cdr;
+  else
+    exceptionWithObject(first, "is not a list");
+}
+
+Object *primitiveCons(Object **args, GC_PARAM) {
+  GC_TRACE(gcFirst, (*args)->car);
+  GC_TRACE(gcSecond, (*args)->cdr->car);
+
+  return newCons(gcFirst, gcSecond, GC_ROOTS);
+}
+
+Object *primitivePrint(Object **args, GC_PARAM) {
+  writeObject((*args)->car, true, stdout);
+  fputc(' ', stdout);
+  return (*args)->car;
+}
+
+Object *primitivePrinc(Object **args, GC_PARAM) {
+  writeObject((*args)->car, false, stdout);
+  fputc(' ', stdout);
+  return (*args)->car;
+}
+
+Object *primitiveNewline(Object **args, GC_PARAM) {
+  fputc('\n', stdout);
+  return n;
+}
+
+Object *primitiveRead(Object **args, GC_PARAM) {
+  Stream stream = { STREAM_TYPE_FILE, .fd = STDIN_FILENO };
+
+  fflush(stdout);
+  if (peekNext(&stream) == EOF) {
+    fputc('\n', stdout);
+    return n;
+  }
+  return readExpr(&stream, GC_ROOTS);
+}
+
+Object *primitiveTime(Object **args, GC_PARAM) {
+  time_t secs;
+  struct tm *today;
+
+  time(&secs);
+  today = localtime(&secs);
+
+  GC_TRACE(gcSymbol, nil);
+  GC_TRACE(gcCons, nil);
+
+  *gcSymbol = newNumber(today->tm_gmtoff, GC_ROOTS);
+  *gcCons = newCons(gcSymbol, gcCons, GC_ROOTS);
+  *gcCons = newCons(today->tm_isdst ? &t : &f, gcCons, GC_ROOTS);
+
+  int tmp [7] = {
+    today->tm_wday, today->tm_year+1900, today->tm_mon+1, today->tm_mday,
+    today->tm_hour, today->tm_min, today->tm_sec
+  };
+
+  for (int i = 0; i < 7; i++) {
+    *gcSymbol = newNumber(tmp[i], GC_ROOTS);
+    *gcCons = newCons(gcSymbol, gcCons, GC_ROOTS);
+  }
+
+  return *gcCons;
+}
+
+Object *primitiveRandom(Object **args, GC_PARAM) {
+    srandom((unsigned int)(seed + time(NULL)));
+    double number = (double)random();
+    seed = (unsigned int)number;
+
+    if (*args == nil)
+        return newNumber(number, GC_ROOTS);
+    else
+        return
+            newNumber(((unsigned int)number % (unsigned int)(*args)->car->number),
+                      GC_ROOTS);
+}
+
+#define DEFINE_PRIMITIVE_ARITHMETIC(name, op, init, datatype)           \
+  Object *name(Object **args, GC_PARAM) {                               \
+    if (*args == nil)                                                   \
+      return newNumber(init, GC_ROOTS);                                 \
+    else if ((*args)->car->type != TYPE_NUMBER)                         \
+      exceptionWithObject((*args)->car, "is not a number");             \
+    else {                                                              \
+      Object *object, *rest;                                            \
+                                                                        \
+      if ((*args)->cdr == nil) {                                        \
+        object = newNumber(init, GC_ROOTS);                             \
+        rest = *args;                                                   \
+      } else {                                                          \
+        GC_TRACE(gcFirst, (*args)->car);                                \
+        object = newObjectFrom(gcFirst, GC_ROOTS);                      \
+        rest = (*args)->cdr;                                            \
+      }                                                                 \
+                                                                        \
+      for (; rest != nil; rest = rest->cdr) {                           \
+        if (rest->car->type != TYPE_NUMBER)                             \
+          exceptionWithObject(rest->car, "is not a number");            \
+                                                                        \
+        object->number =                                                \
+          (datatype)object->number op (datatype)rest->car->number;      \
+      }                                                                 \
+                                                                        \
+      return object;                                                    \
+    }                                                                   \
+  }
+
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveAdd,       +, 0, double)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveSubtract,  -, 0, double)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveMultiply,  *, 1, double)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveDivide,    /, 1, double)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveRemainder, %, 1, int   )
+
+#define DEFINE_PRIMITIVE_RELATIONAL(name, op, until_the_end)            \
+  Object *name(Object **args, GC_PARAM) {                               \
+    if ((*args)->car->type != TYPE_NUMBER)                              \
+      exceptionWithObject((*args)->car, "is not a number");             \
+    else {                                                              \
+      Object *rest = *args;                                             \
+      bool result = until_the_end;                                      \
+                                                                        \
+      for (; (result == until_the_end) && rest->cdr != nil;             \
+           rest = rest->cdr) {                                          \
+        if (rest->cdr->car->type != TYPE_NUMBER)                        \
+          exceptionWithObject(rest->cdr->car, "is not a number");       \
+        else if (until_the_end)                                         \
+          result &= rest->car->number op rest->cdr->car->number;        \
+        else                                                            \
+          result = rest->car->number op rest->cdr->car->number;         \
+      }                                                                 \
+      return result ? t : f;                                            \
+    }                                                                   \
+  }
+
+DEFINE_PRIMITIVE_RELATIONAL(primitiveDifferent,    !=, false)
+/* DEFINE_PRIMITIVE_RELATIONAL(primitiveEqual,        ==, true) */
+DEFINE_PRIMITIVE_RELATIONAL(primitiveLess,         < , true)
+/* DEFINE_PRIMITIVE_RELATIONAL(primitiveLessEqual,    <=, true) */
+DEFINE_PRIMITIVE_RELATIONAL(primitiveGreater,      > , true)
+/* DEFINE_PRIMITIVE_RELATIONAL(primitiveGreaterEqual, >=, true) */
+
+typedef struct Primitive {
+  char *name;
+  int nMinArgs, nMaxArgs;
+  Object *(* eval)(Object **args, GC_PARAM);
+} Primitive;
+
+Primitive primitives[] = {
+  { "eval",    1,  1  /* special form */    },
+  { "quote",   1,  1  /* special form */    },
+  { "say",     1,  1  /* special form */    },
+  { "set",     0, -2  /* special form */    },
+  { "prog",    0, -1  /* special form */    },
+  { "progs",   1, -1  /* special form */    },
+  /* { "if",      2,  3  /\* special form *\/    }, */
+  { "cond",    0, -1  /* special form */    },
+  { "fill",    0, -1  /* special form */    },
+  { "lambda",  1, -1  /* special form */    },
+  { "macro",   1, -1  /* special form */    },
+  { "space",   1,  1, primitiveSpace        },
+  { "atom",    1,  1, primitiveAtom         },
+  /* { "eq",      2,  2, primitiveEq           }, */
+  { "dif",     2,  2, primitiveDif          },
+  { "car",     1,  1, primitiveCar          },
+  { "cdr",     1,  1, primitiveCdr          },
+  { "cons",    2,  2, primitiveCons         },
+  { "print",   1,  1, primitivePrint        },
+  { "princ",   1,  1, primitivePrinc        },
+  { "newline", 0,  0, primitiveNewline      },
+  { "read",    0,  0, primitiveRead         },
+  { "time",    0,  0, primitiveTime         },
+  { "random",  0,  1, primitiveRandom       },
+  { "+",       0, -1, primitiveAdd          },
+  { "-",       1, -1, primitiveSubtract     },
+  { "*",       0, -1, primitiveMultiply     },
+  { "/",       1, -1, primitiveDivide       },
+  { "%",       1, -1, primitiveRemainder    },
+  /* { "=",       1, -1, primitiveEqual        }, */
+  { "!",       1, -1, primitiveDifferent    },
+  { "<",       1, -1, primitiveLess         },
+  /* { "<=",      1, -1, primitiveLessEqual    }, */
+  { ">",       1, -1, primitiveGreater      },
+  /* { ">=",      1, -1, primitiveGreaterEqual } */
+};
+
+// Special forms handled by evalExpr. Must be in the same order as above.
+enum {
+  PRIMITIVE_EVAL,
+  PRIMITIVE_QUOTE,
+  PRIMITIVE_SAY,
+  PRIMITIVE_SET,
+  PRIMITIVE_PROG,
+  PRIMITIVE_PROGS,
+  /* PRIMITIVE_IF, */
+  PRIMITIVE_COND,
+  PRIMITIVE_FILL,
+  PRIMITIVE_LAMBDA,
+  PRIMITIVE_MACRO
+};
+
+// EVALUATION /////////////////////////////////////////////////////////////////
+
+/* Scheme-style tail recursive evaluation. evalProg, evalProgs, evalCond, and
+ * PRIMITIVE_EVAL, return the object in the tail recursive position to be
+ * evaluated by evalExpr. Macros are expanded in-place the first time they are
+ * evaluated.
+ */
+
+bool isSymbolAPrimitive(Object *symbol) {
+  int nPrimitives = sizeof (primitives) / sizeof (primitives[0]);
+  for (int i = 0; i < nPrimitives; ++i)
+    if (!strcmp(primitives[i].name, symbol->string)) return true;
+
+  return false;
+}
+
+Object *evalSet(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else {
+    GC_TRACE(gcVar, (*args)->car);
+    GC_TRACE(gcVal, (*args)->cdr->car);
+
+    *gcVar = evalExpr(gcVar, env, GC_ROOTS);
+
+    if (*gcVar == nil || *gcVar == n || *gcVar == t || *gcVar == f)
+      exceptionWithObject(*gcVar, "is a constant and cannot be set");
+    else if (isSymbolAPrimitive(*gcVar))
+      exceptionWithObject(*gcVar, "is a primitive name and cannot be set");
+    else if ((*gcVar)->type != TYPE_SYMBOL)
+      exceptionWithObject(*gcVar, "is not an atom and cannot be set");
+
+    *gcVal = evalExpr(gcVal, env, GC_ROOTS);
+    envSet(gcVar, gcVal, env, GC_ROOTS);
+
+    if ((*args)->cdr->cdr == nil)
+      return *gcVal;
+    else {
+      GC_TRACE(gcArgs, (*args)->cdr->cdr);
+      return evalSet(gcArgs, env, GC_ROOTS);
+    }
+  }
+}
+
+Object *evalProg(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcObject, nil);
+  GC_TRACE(gcCdr, nil);
+
+  for (;;) {
+    if (*args == nil)
+      return n;
+    else if ((*args)->cdr == nil)
+      return (*args)->car;
+    else {
+      *gcObject = (*args)->car;
+      *gcCdr = (*args)->cdr;
+
+      evalExpr(gcObject, env, GC_ROOTS);
+      *args = *gcCdr;
+      /* return evalProg(gcCdr, env, GC_ROOTS); */
+    }
+  }
+}
+
+Object *progs1(Object **stop, Object **body, Object **env, GC_PARAM) {
+  GC_TRACE(gcObject, nil);
+  GC_TRACE(gcCdr, nil);
+
+  for (;;) {
+    if (*body == nil)
+      return *stop;
+    else if ((*body)->cdr == nil)
+      return (*body)->car;
+    else {
+      /* GC_TRACE(gcEnv, *env); */
+      /* GC_TRACE(gcBody, nil); */
+      /* GC_TRACE(gcStop, nil); */
+
+      /* if ((*stop)->type == TYPE_LAMBDA) { */
+      /*   *gcBody = (*stop)->body; */
+      /*   *gcEnv = newEnv(stop, gcBody, GC_ROOTS); */
+      /*   *gcStop = evalExpr(gcBody, gcEnv, GC_ROOTS); */
+
+      /*   if (*gcStop == t) */
+      /*     return *gcObject; */
+      /* } */
+
+      *gcObject = (*body)->car;
+      *gcCdr = (*body)->cdr;
+
+      *gcObject = evalExpr(gcObject, env, GC_ROOTS);
+
+      if (*gcObject == *stop)
+        return *gcObject;
+
+      *body = *gcCdr;
+      /* return progs1(stop, gcCdr, env, GC_ROOTS); */
+    }
+  }
+}
+
+Object *evalProgs(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcStop, (*args)->car);
+  GC_TRACE(gcBody, (*args)->cdr);
+
+  *gcStop = evalExpr(gcStop, env, GC_ROOTS);
+
+  if ((*gcStop)->type != TYPE_SYMBOL)
+    exceptionWithObject(*gcStop, "is not a symbol");
+
+  return progs1(gcStop, gcBody, env, GC_ROOTS);
+}
+
+/* Object *evalIf(Object **args, Object **env, GC_PARAM) {
+ *   GC_TRACE(gcObject, (*args)->car);
+ *
+ *   if (evalExpr(gcObject, env, GC_ROOTS) != nil)
+ *     return (*args)->cdr->car;
+ *   else if ((*args)->cdr->cdr != nil)
+ *     return (*args)->cdr->cdr->car;
+ *   else
+ *     return n;
+ * }
+ */
+
+Object *evalCond(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else if ((*args)->car->type != TYPE_CONS)
+    exceptionWithObject((*args)->car, "is not a list");
+  else {
+    GC_TRACE(gcCar, (*args)->car->car);
+    GC_TRACE(gcCdr, (*args)->car->cdr);
+
+    if (*gcCdr == nil) return *gcCar;
+
+    *gcCar = evalExpr(gcCar, env, GC_ROOTS);
+    if (*gcCar == n)
+      return n;
+    else if (*gcCar != f)
+      return evalProg(gcCdr, env, GC_ROOTS);
+    else {
+      GC_TRACE(gcArgs, (*args)->cdr);
+      return evalCond(gcArgs, env, GC_ROOTS);
+    }
+  }
+}
+
+Object *evalFill(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else if ((*args)->car->type != TYPE_CONS)
+    exceptionWithObject((*args)->car, "is not a list");
+  else {
+    GC_TRACE(gcCar, (*args)->car->car);
+    GC_TRACE(gcCdr, (*args)->car->cdr);
+
+    if (*gcCdr == nil) return *gcCar;
+
+    *gcCar = evalExpr(gcCar, env, GC_ROOTS);
+    if (*gcCar == n)
+      return n;
+    else if (*gcCar == f)
+      return evalProg(gcCdr, env, GC_ROOTS);
+    else {
+      GC_TRACE(gcArgs, (*args)->cdr);
+      return evalFill(gcArgs, env, GC_ROOTS);
+    }
+  }
+}
+
+Object *evalLambda(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcParams, (*args)->car);
+  GC_TRACE(gcBody, (*args)->cdr);
+
+  return newLambda(gcParams, gcBody, env, GC_ROOTS);
+}
+
+Object *evalMacro(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcParams, (*args)->car);
+  GC_TRACE(gcBody, (*args)->cdr);
+
+  return newMacro(gcParams, gcBody, env, GC_ROOTS);
+}
+
+Object *expandMacro(Object **macro, Object **args, GC_PARAM) {
+  GC_TRACE(gcEnv, newEnv(macro, args, GC_ROOTS));
+  GC_TRACE(gcBody, (*macro)->body);
+
+  GC_TRACE(gcObject, evalProg(gcBody, gcEnv, GC_ROOTS));
+  *gcObject = evalExpr(gcObject, gcEnv, GC_ROOTS);
+
+  return *gcObject;
+}
+
+Object *expandMacroTo(Object **macro, Object **args, Object **cons, GC_PARAM) {
+  GC_TRACE(gcObject, expandMacro(macro, args, GC_ROOTS));
+
+  if ((*gcObject)->type == TYPE_CONS) {
+    (*cons)->car = (*gcObject)->car;
+    (*cons)->cdr = (*gcObject)->cdr;
+  } else {
+    (*cons)->car = newSymbol("prog", GC_ROOTS);
+    (*cons)->cdr = newCons(gcObject, &nil, GC_ROOTS);
+  }
+
+  return *cons;
+}
+
+Object *evalList(Object **args, Object **env, GC_PARAM) {
+  if ((*args)->type != TYPE_CONS)
+    return evalExpr(args, env, GC_ROOTS);
+  else {
+    GC_TRACE(gcObject, (*args)->car);
+    GC_TRACE(gcArgs, (*args)->cdr);
+
+    *gcObject = evalExpr(gcObject, env, GC_ROOTS);
+    *gcArgs = evalList(gcArgs, env, GC_ROOTS);
+
+    return newCons(gcObject, gcArgs, GC_ROOTS);
+  }
+}
+
+Object *evalExpr(Object **object, Object **env, GC_PARAM) {
+  GC_TRACE(gcObject, *object);
+  GC_TRACE(gcEnv, *env);
+
+  GC_TRACE(gcFunc, nil);
+  GC_TRACE(gcArgs, nil);
+  GC_TRACE(gcBody, nil);
+
+  for (;;) {
+    if ((*gcObject)->type == TYPE_SYMBOL)
+      return envLookup(*gcObject, *gcEnv);
+    if ((*gcObject)->type != TYPE_CONS)
+      return *gcObject;
+
+    *gcFunc = (*gcObject)->car;
+    *gcArgs = (*gcObject)->cdr;
+
+    *gcFunc = evalExpr(gcFunc, gcEnv, GC_ROOTS);
+    *gcBody = nil;
+
+    if ((*gcFunc)->type == TYPE_LAMBDA) {
+      *gcBody = (*gcFunc)->body;
+      *gcArgs = evalList(gcArgs, gcEnv, GC_ROOTS);
+      *gcEnv = newEnv(gcFunc, gcArgs, GC_ROOTS);
+      *gcObject = evalProg(gcBody, gcEnv, GC_ROOTS);
+    } else if ((*gcFunc)->type == TYPE_MACRO) {
+      *gcObject = expandMacroTo(gcFunc, gcArgs, gcObject, GC_ROOTS);
+    } else if ((*gcFunc)->type == TYPE_PRIMITIVE) {
+      Primitive *primitive = &primitives[(*gcFunc)->primitive];
+      int nArgs = 0;
+
+      for (Object *args = *gcArgs; args != nil; args = args->cdr, nArgs++)
+        if (args->type != TYPE_CONS)
+          exceptionWithObject(args, "is not a list");
+
+      if (nArgs < primitive->nMinArgs)
+        exceptionWithObject(*gcFunc, "expects at least %d arguments",
+                            primitive->nMinArgs);
+      if (nArgs > primitive->nMaxArgs && primitive->nMaxArgs >= 0)
+        exceptionWithObject(*gcFunc, "expects at most %d arguments",
+                            primitive->nMaxArgs);
+      if (primitive->nMaxArgs < 0 && nArgs % -primitive->nMaxArgs)
+        exceptionWithObject(*gcFunc, "expects a multiple of %d arguments",
+                            -primitive->nMaxArgs);
+
+      switch ((*gcFunc)->primitive) {
+      case PRIMITIVE_EVAL:   *gcArgs = (*gcArgs)->car;
+                             *gcObject = evalExpr(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_QUOTE:  return (*gcArgs)->car;
+      case PRIMITIVE_SAY:    *gcArgs = (*gcArgs)->car;
+                             return newCons(&nil, gcArgs, GC_ROOTS);
+      case PRIMITIVE_SET:    return evalSet(gcArgs, gcEnv, GC_ROOTS);
+      case PRIMITIVE_PROG:   *gcObject = evalProg(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_PROGS:  *gcObject = evalProgs(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+        /* case PRIMITIVE_IF:     *gcObject = evalIf(gcArgs, gcEnv, GC_ROOTS);
+         *                        break;
+         */
+      case PRIMITIVE_COND:   *gcObject = evalCond(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_FILL:   *gcObject = evalFill(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_LAMBDA: return evalLambda(gcArgs, gcEnv, GC_ROOTS);
+      case PRIMITIVE_MACRO:  return evalMacro(gcArgs, gcEnv, GC_ROOTS);
+      default:               *gcArgs = evalList(gcArgs, gcEnv, GC_ROOTS);
+                             return primitive->eval(gcArgs, GC_ROOTS);
+      }
+    } else
+      exceptionWithObject(*gcFunc, "is not a function");
+  }
+}
+
+// STANDARD LIBRARY ///////////////////////////////////////////////////////////
+
+#define LISP(...) #__VA_ARGS__
+
+static char *stdlib = LISP(
+  (set (quote list) (lambda args args))
+
+  (set (quote defmacro) (macro (name params . body)
+    (list (quote set) (list quote name) (list (quote macro) params . body))))
+
+  (defmacro defun (name params . body)
+    (list (quote set) (list quote name) (list (quote lambda) params . body)))
+
+  (defun not (x) (fill ((dif x n) n)
+                       (x t)
+                       (f f)))
+
+  (defun ap (x) (not (space x)))
+
+  (defun listp (x) (not (atom x)))
+
+  (defun zerop (x) (not (! x 0)))
+
+  (defmacro and args
+    (fill ((ap args) t)
+          ((ap (cdr args)) (car args))
+          (f (list (quote fill)
+                   (list (list (quote not) (car args))
+                         (cons (quote and) (cdr args)))
+                   (list (quote f) (quote f))))))
+
+  (defun map (func xs)
+    (fill ((ap xs) ())
+          (f (cons (func (car xs)) (map func (cdr xs))))))
+
+  (defmacro or args
+    (fill ((ap args) f)
+          (f (cons (quote fill)
+                   (append (map (lambda (x) (list (list (quote not) x) x))
+                                args)
+                           (list (list f f)))))))
+
+  (defun consp (x) (and (listp x) (ap x)))
+
+  (defun differ (x y)
+    (fill ((or (consp x) (consp y)) (dif x y))
+          (f (or (differ (car x) (car y))
+                 (differ (cdr x) (cdr y))))))
+
+  (defun nth (num xs)
+    (fill ((dif num 0) (car xs))
+          (f (nth (- num 1) (cdr xs)))))
+
+  (defun append (xs y)
+    (fill ((ap xs) y)
+          (f (cons (car xs) (append (cdr xs) y)))))
+);
+
+// MAIN ///////////////////////////////////////////////////////////////////////
+
+Object *newRootEnv(GC_PARAM) {
+  GC_TRACE(gcEnv, newEnv(&nil, &nil, GC_ROOTS));
+  GC_TRACE(gcVar, nil);
+  GC_TRACE(gcVal, nil);
+
+  // add constants
+  envSet(&nil, &nil, gcEnv, GC_ROOTS);
+  envSet(&n, &n, gcEnv, GC_ROOTS);
+  envSet(&t, &t, gcEnv, GC_ROOTS);
+  envSet(&f, &f, gcEnv, GC_ROOTS);
+
+  // add primitives
+  int nPrimitives = sizeof (primitives) / sizeof (primitives[0]);
+
+  for (int i = 0; i < nPrimitives; ++i) {
+    *gcVar = newSymbol(primitives[i].name, GC_ROOTS);
+    *gcVal = newPrimitive(i, primitives[i].name, GC_ROOTS);
+
+    envSet(gcVar, gcVal, gcEnv, GC_ROOTS);
+  }
+
+  // add standard library
+  Stream stream = { STREAM_TYPE_STRING, .buffer = stdlib };
+  GC_TRACE(gcObject, nil);
+
+  while (peekNext(&stream) != EOF) {
+    *gcObject = nil;
+    *gcObject = readExpr(&stream, GC_ROOTS);
+    evalExpr(gcObject, gcEnv, GC_ROOTS);
+  }
+
+  return *gcEnv;
+}
diff --git a/liblali.h b/liblali.h
new file mode 100644
index 0000000..797587d
--- /dev/null
+++ b/liblali.h
@@ -0,0 +1,362 @@
+/*
+ * lali (Lali Another Lisp Implementation)
+ *
+ * Author: Daniel Cerqueira (dan.git@lispclub.com)
+ * Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+ * Version: 0.0
+ * Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+ *           computer programming language
+ * Homepage: https://gitlab.com/alexandre1985/lali
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Copyright (C) 2025 Daniel Cerqueira
+ *
+ * This file is part of lali.
+ *
+ * lali is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, see <https://www.gnu.org/licenses/>.
+ *
+ *
+ * lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/>
+ * version from 2016, written by Matthias Pirstitz, which is released to public
+ * domain under Unlicense <https://unlicense.org/>.
+ */
+
+#ifndef LIBLALI_H
+#define LIBLALI_H
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+
+
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+#define MAP_ANONYMOUS        MAP_ANON
+#endif
+
+typedef struct Object Object;
+
+typedef enum Type {
+  TYPE_NUMBER,
+  TYPE_STRING,
+  TYPE_SYMBOL,
+  TYPE_CONS,
+  TYPE_LAMBDA,
+  TYPE_MACRO,
+  TYPE_PRIMITIVE,
+  TYPE_ENV
+} Type;
+
+struct Object {
+  Type type;
+  size_t size;
+  union {
+    struct { double number; };                      // number
+    struct { char string[sizeof (Object *[3])]; };  // string, symbol
+    struct { Object *car, *cdr; };                  // cons
+    struct { Object *params, *body, *env; };        // lambda, macro
+    struct { int primitive; char *name; };          // primitive
+    struct { Object *parent, *vars, *vals; };       // env
+    struct { Object *forward; };                    // forwarding pointer
+  };
+};
+
+extern Object *symbols;
+extern Object *nil;
+extern Object *n;
+extern Object *t;
+extern Object *f;
+
+typedef enum StreamType {
+  STREAM_TYPE_STRING,
+  STREAM_TYPE_FILE
+} StreamType;
+
+typedef struct Stream {
+  StreamType type;
+  char *buffer;
+  int fd;
+  size_t length, capacity;
+  off_t offset, size;
+} Stream;
+
+typedef struct Memory {
+  size_t capacity, fromOffset, toOffset;
+  void *fromSpace, *toSpace;
+} Memory;
+
+extern jmp_buf exceptionEnv;
+
+// EXCEPTION HANDLING /////////////////////////////////////////////////////////
+
+#define exception(...)       exceptionWithObject(NULL, __VA_ARGS__)
+
+#ifdef __GNUC__
+void exceptionWithObject(Object *object, char *format, ...)
+  __attribute__ ((noreturn, format(printf, 2, 3)));
+#endif
+
+void exceptionWithObject(Object *object, char *format, ...);
+
+// GARBAGE COLLECTION /////////////////////////////////////////////////////////
+
+/* This implements Cheney's copying garbage collector, with which memory is
+ * divided into two equal halves (semispaces): from- and to-space. From-space
+ * is where new objects are allocated, whereas to-space is used during garbage
+ * collection.
+ *
+ * When garbage collection is performed, objects that are still in use (live)
+ * are copied from from-space to to-space. To-space then becomes the new
+ * from-space and vice versa, thereby discarding all objects that have not
+ * been copied.
+ *
+ * Our garbage collector takes as input a list of root objects. Objects that
+ * can be reached by recursively traversing this list are considered live and
+ * will be moved to to-space. When we move an object, we must also update its
+ * pointer within the list to point to the objects new location in memory.
+ *
+ * However, this implies that our interpreter cannot use raw pointers to
+ * objects in any function that might trigger garbage collection (or risk
+ * causing a SEGV when accessing an object that has been moved). Instead,
+ * objects must be added to the list and then only accessed through the
+ * pointer inside the list.
+ *
+ * Thus, whenever we would have used a raw pointer to an object, we use a
+ * pointer to the pointer inside the list instead:
+ *
+ *   function:              pointer to pointer inside list (Object **)
+ *                                  |
+ *                                  v
+ *   list of root objects:  pointer to object (Object *)
+ *                                  |
+ *                                  v
+ *   semispace:             object in memory
+ *
+ * GC_ROOTS and GC_PARAM are used to pass the list from function to function.
+ *
+ * GC_TRACE adds an object to the list and declares a variable which points to
+ * the objects pointer inside the list.
+ *
+ *   GC_TRACE(gcX, X):  add object X to the list and declare Object **gcX
+ *                      to point to the pointer to X inside the list.
+ */
+
+#define GC_ROOTS             gcRoots
+#define GC_PARAM             Object *GC_ROOTS
+
+#define GC_PASTE1(name, id)  name ## id
+#define GC_PASTE2(name, id)  GC_PASTE1(name, id)
+#define GC_UNIQUE(name)      GC_PASTE2(name, __LINE__)
+
+#define GC_TRACE(name, init)                                                     \
+  Object GC_UNIQUE(GC_ROOTS) = { TYPE_CONS, .car = init, .cdr = GC_ROOTS };      \
+  Object **name = &GC_UNIQUE(GC_ROOTS).car;                                      \
+  GC_ROOTS = &GC_UNIQUE(GC_ROOTS)
+
+Object *gcMoveObject(Object *object);
+
+void gc(GC_PARAM);
+
+// MEMORY MANAGEMENT //////////////////////////////////////////////////////////
+
+size_t memoryAlign(size_t size, size_t alignment);
+
+Object *memoryAllocObject(Type type, size_t size, GC_PARAM);
+
+// CONSTRUCTING OBJECTS ///////////////////////////////////////////////////////
+
+Object *newObject(Type type, GC_PARAM);
+
+Object *newObjectFrom(Object **from, GC_PARAM);
+
+Object *newNumber(double number, GC_PARAM);
+
+Object *newObjectWithString(Type type, size_t size, GC_PARAM);
+
+Object *newStringWithLength(char *string, size_t length, GC_PARAM);
+
+Object *newString(char *string, GC_PARAM);
+
+Object *newCons(Object **car, Object **cdr, GC_PARAM);
+
+Object *newSymbolWithLength(char *string, size_t length, GC_PARAM);
+
+Object *newSymbol(char *string, GC_PARAM);
+
+Object *newObjectWithClosure(Type type, Object **params, Object **body, Object **env, GC_PARAM);
+
+Object *newLambda(Object **params, Object **body, Object **env, GC_PARAM);
+
+Object *newMacro(Object **params, Object **body, Object **env, GC_PARAM);
+
+Object *newPrimitive(int primitive, char *name, GC_PARAM);
+
+Object *newEnv(Object **func, Object **vals, GC_PARAM);
+
+// STREAM INPUT ///////////////////////////////////////////////////////////////
+
+/* The purpose of the stream functions is to provide an abstraction over file
+ * and string inputs. In order to accommodate the REPL, we need to be able to
+ * process character special files (such as stdin) character by character and
+ * evaluate expressions as they are being entered.
+ */
+
+int streamGetc(Stream *stream);
+
+Stream *streamSeek(Stream *stream, int offset);
+
+int streamPeek(Stream *stream);
+
+// READING S-EXPRESSIONS //////////////////////////////////////////////////////
+
+Object *readExpr(Stream *stream, GC_PARAM);
+
+int readNext(Stream *stream);
+
+int initialReadNext(Stream *stream);
+
+int peekForward(Stream *stream, bool shebang);
+
+int peekNext(Stream *stream);
+
+int readWhile(Stream *stream, int (*predicate)(int ch));
+
+Object *readUnary(Stream *stream, char *symbol, GC_PARAM);
+
+Object *readString(Stream *stream, GC_PARAM);
+
+int isSymbolChar(int ch);
+
+Object *readNumberOrSymbol(Stream *stream, GC_PARAM);
+
+Object *reverseList(Object *list);
+
+Object *readList(Stream *stream, GC_PARAM);
+
+// WRITING OBJECTS ////////////////////////////////////////////////////////////
+
+void writeObject(Object *object, bool readably, FILE *file);
+
+// ENVIRONMENT ////////////////////////////////////////////////////////////////
+
+/* An environment consists of a pointer to its parent environment (if any) and
+ * two parallel lists - vars and vals.
+ *
+ * Case 1 - vars is a regular list:
+ *   vars: (a b c), vals: (1 2 3)        ; a = 1, b = 2, c = 3
+ *
+ * Case 2 - vars is a dotted list:
+ *   vars: (a b . c), vals: (1 2)        ; a = 1, b = 2, c = nil
+ *   vars: (a b . c), vals: (1 2 3)      ; a = 1, b = 2, c = (3)
+ *   vars: (a b . c), vals: (1 2 3 4 5)  ; a = 1, b = 2, c = (3 4 5)
+ *
+ * Case 3 - vars is a symbol:
+ *   vars: a, vals: nil                  ; a = nil
+ *   vars: a, vals: (1)                  ; a = (1)
+ *   vars: a, vals: (1 2 3)              ; a = (1 2 3)
+ *
+ * Case 4 - vars and vals are both nil:
+ *   vars: nil, vals: nil
+ */
+
+Object *envLookup(Object *var, Object *env);
+
+Object *envAdd(Object **var, Object **val, Object **env, GC_PARAM);
+
+Object *envSet(Object **var, Object **val, Object **env, GC_PARAM);
+
+// PRIMITIVES /////////////////////////////////////////////////////////////////
+
+Object *primitiveSpace(Object **args, GC_PARAM);
+
+Object *primitiveAtom(Object **args, GC_PARAM);
+
+/* Object *primitiveEq(Object **args, GC_PARAM);
+ */
+
+Object *primitiveDif(Object **args, GC_PARAM);
+
+Object *primitiveCar(Object **args, GC_PARAM);
+
+Object *primitiveCdr(Object **args, GC_PARAM);
+
+Object *primitiveCons(Object **args, GC_PARAM);
+
+Object *primitivePrint(Object **args, GC_PARAM);
+
+Object *primitivePrinc(Object **args, GC_PARAM);
+
+Object *primitiveNewline(Object **args, GC_PARAM);
+
+Object *primitiveRead(Object **args, GC_PARAM);
+
+Object *primitiveTime(Object **args, GC_PARAM);
+
+Object *primitiveRandom(Object **args, GC_PARAM);
+
+Object *primitiveAdd(Object **args, GC_PARAM);
+
+Object *primitiveSubtract(Object **args, GC_PARAM);
+
+Object *primitiveMultiply(Object **args, GC_PARAM);
+
+Object *primitiveDivide(Object **args, GC_PARAM);
+
+Object *primitiveRemainder(Object **args, GC_PARAM);
+
+// EVALUATION /////////////////////////////////////////////////////////////////
+
+/* Scheme-style tail recursive evaluation. evalProg, evalProgs, evalCond, and
+ * PRIMITIVE_EVAL, return the object in the tail recursive position to be
+ * evaluated by evalExpr. Macros are expanded in-place the first time they are
+ * evaluated.
+ */
+
+Object *evalExpr(Object **object, Object **env, GC_PARAM);
+
+Object *evalSet(Object **args, Object **env, GC_PARAM);
+
+Object *evalProg(Object **args, Object **env, GC_PARAM);
+
+Object *progs1(Object **stop, Object **body, Object **env, GC_PARAM);
+
+Object *evalProgs(Object **args, Object **env, GC_PARAM);
+
+Object *evalCond(Object **args, Object **env, GC_PARAM);
+
+Object *evalFill(Object **args, Object **env, GC_PARAM);
+
+Object *evalLambda(Object **args, Object **env, GC_PARAM);
+
+Object *evalMacro(Object **args, Object **env, GC_PARAM);
+
+Object *expandMacro(Object **macro, Object **args, GC_PARAM);
+
+Object *expandMacroTo(Object **macro, Object **args, Object **cons, GC_PARAM);
+
+Object *evalList(Object **args, Object **env, GC_PARAM);
+
+Object *evalRead(GC_PARAM);
+
+Object *newRootEnv(GC_PARAM);
+
+#endif
diff --git a/test/main.lali b/test/main.lali
new file mode 100644
index 0000000..a3e4b9a
--- /dev/null
+++ b/test/main.lali
@@ -0,0 +1,40 @@
+(defun test (test-expr res)
+  (princ
+   (list (fill
+          ((differ (eval test-expr) res) 'ok)
+          ('f 'fail))
+         '--> test-expr))
+  (newline))
+
+;; atom
+(test '(atom 'a) t)
+(test '(atom '(x . a)) f)
+;(test '(atom 'a) undef)
+
+;; dif
+(test '(dif 'a 'b) t)
+(test '(dif 'a 'a) f)
+(test '(dif 'a '(b . c)) t)
+(test '(dif '(b . c) '(b . c)) t)
+
+;; car
+(test '(car '(a . b)) 'a)
+(test '(car '((a . b) . c)) '(a . b))
+;(test '(car 'a) undef)
+
+;; cdr
+(test '(cdr '(a . b)) 'b)
+(test '(cdr '((a . b) . c)) 'c)
+;(test '(cdr 'a) undef)
+
+;; cons
+(test '(cons 'a 'b) '(a . b))
+(test '(cons '(a . b) 'c) '((a . b) . c))
+
+;; or
+(test '(or t (car 'a)) t)
+;(test '(or (car 'a) t) undef)
+
+;; and
+(test '(and f (car 'a)) f)
+;(test '(and (car 'a) f) undef)
diff --git a/test/other/executables/emacs.el b/test/other/executables/emacs.el
new file mode 100755
index 0000000..e7e2efc
--- /dev/null
+++ b/test/other/executables/emacs.el
@@ -0,0 +1,3 @@
+#!/usr/local/bin/emacs --script
+
+(princ 'i)
diff --git a/test/other/executables/empty.lisp b/test/other/executables/empty.lisp
new file mode 100755
index 0000000..e69de29
--- /dev/null
+++ b/test/other/executables/empty.lisp
diff --git a/test/other/executables/script.lali b/test/other/executables/script.lali
new file mode 100755
index 0000000..934323d
--- /dev/null
+++ b/test/other/executables/script.lali
@@ -0,0 +1,4 @@
+#!/home/guest/me/programming/desktop/lisp/interpreter/lali/lali -c
+
+(princ "ola")
+(newline)
diff --git a/test/other/lexical.lali b/test/other/lexical.lali
new file mode 100644
index 0000000..d8d94e2
--- /dev/null
+++ b/test/other/lexical.lali
@@ -0,0 +1,15 @@
+(set 'a '1)
+
+(defun j ()
+  (princ a)
+  (set 'a (+ a 1)))
+
+(j)
+(j)
+(princ a)
+
+(defun i ()
+  (set 'b 9))
+
+(i)
+(princ b)
diff --git a/test/other/mundo.lali b/test/other/mundo.lali
new file mode 100644
index 0000000..19756fe
--- /dev/null
+++ b/test/other/mundo.lali
@@ -0,0 +1,4 @@
+(princ 'proc)
+(princ (list a 'ola))
+(print "mundo")
+(print '(ate breve))
diff --git a/test/other/ola.lali b/test/other/ola.lali
new file mode 100644
index 0000000..d62a537
--- /dev/null
+++ b/test/other/ola.lali
@@ -0,0 +1,3 @@
+(princ "ola")
+(newline)
+(set 'a 1)
diff --git a/test/other/universal.lali b/test/other/universal.lali
new file mode 100644
index 0000000..6b38b19
--- /dev/null
+++ b/test/other/universal.lali
@@ -0,0 +1 @@
+(princ 'i)
diff --git a/work-in-progress/Makefile b/work-in-progress/Makefile
new file mode 100644
index 0000000..f136822
--- /dev/null
+++ b/work-in-progress/Makefile
@@ -0,0 +1,94 @@
+# lali (Lali Another Lisp Implementation)
+#
+# Author: Daniel Cerqueira (dan.git@lispclub.com)
+# Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+# Version: 0.0
+# Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+#           computer programming language
+# Homepage: https://gitlab.com/alexandre1985/lali
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Copyright (C) 2025 Daniel Cerqueira
+#
+# This file is part of lali.
+#
+# lali is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 3 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, see <https://www.gnu.org/licenses/>.
+#
+#
+# lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/> version
+# from 2016, written by Matthias Pirstitz, which is released to public domain
+# under Unlicense <https://unlicense.org/>.
+
+
+PROGRAM := lali
+LIBOBJECTS := liblali.o
+LIB := lib$(PROGRAM).a
+OBJECTS := $(LIBOBJECTS) lali.o
+HTML := README.html
+
+ifeq ($(shell uname -s), Linux)
+CPPFLAGS += -D_DEFAULT_SOURCE -D_BSD_SOURCE
+endif
+
+CFLAGS += -std=c11 -Wall -pedantic
+
+PREFIX ?= /usr/local
+
+.PHONY: native
+native: CPPFLAGS += -DNDEBUG
+native: CFLAGS   += -march=native -O2
+native: $(PROGRAM)
+
+.PHONY: generic
+generic: CPPFLAGS += -DNDEBUG
+generic: CFLAGS   += -mtune=generic -O2
+generic: $(PROGRAM)
+
+.PHONY: all
+all: CPPFLAGS += -DNDEBUG
+all: CFLAGS   += -march=native -O2
+all: $(PROGRAM) $(LIB) $(HTML)
+
+.PHONY: debug
+debug: CPPFLAGS += -DDEBUG
+debug: CFLAGS   += -g
+debug: LDFLAGS  += -g
+debug: $(PROGRAM)
+
+.PHONY: clean
+clean:
+	$(RM) $(PROGRAM) $(OBJECTS) $(LIB) $(HTML)
+
+.PHONY: lib
+lib: $(LIB)
+
+$(LIB): $(LIBOBJECTS)
+	$(AR) rc $@ $(LIBOBJECTS)
+	ranlib $@
+
+$(PROGRAM): $(OBJECTS)
+	$(CC) $(LDFLAGS) $(OBJECTS) -o $@
+# $(CC) $(LDFLAGS) lali.o -L. -l$(PROGRAM) -o $@
+
+%.o: %.c %.h
+	$(CC) $(CFLAGS) $(CPPFLAGS)  -c -o $@ $<
+
+.PHONY: html
+html: $(HTML)
+
+%.html: %.md
+	md2html -f -o $@ $<
+
+.PHONY: install
+install: native
+	install -D -m 311 -t $(PREFIX)/bin $(PROGRAM)
diff --git a/work-in-progress/TAGS b/work-in-progress/TAGS
new file mode 100644
index 0000000..16adb82
--- /dev/null
+++ b/work-in-progress/TAGS
@@ -0,0 +1,104 @@
+
+lali.c,86
+#define YEARS 50,1540
+void runFile(54,1658
+void runREPL(72,2058
+int main(100,2617
+
+liblali.c,3469
+#define MEMORY_SIZE 50,1540
+static Memory *memory memory
52,1580
+Object *symbols symbols
54,1631
+Object *nil nil
55,1655
+Object *n n
56,1711
+Object *t t
57,1764
+Object *f f
58,1817
+jmp_buf exceptionEnv;60,1871
+void exceptionWithObject(64,1975
+Object *gcMoveObject(gcMoveObject
124,4317
+void gc(146,5016
+size_t memoryAlign(194,6464
+Object *memoryAllocObject(memoryAllocObject
198,6571
+Object *newObject(newObject
227,7559
+Object *newObjectFrom(newObjectFrom
231,7664
+Object *newNumber(newNumber
237,7851
+Object *newObjectWithString(newObjectWithString
243,7996
+Object *newStringWithLength(newStringWithLength
250,8239
+Object *newString(newString
278,9169
+Object *newCons(newCons
282,9280
+Object *newSymbolWithLength(newSymbolWithLength
289,9451
+Object *newSymbol(newSymbol
304,9961
+Object *newObjectWithClosure(newObjectWithClosure
308,10072
+Object *newLambda(newLambda
330,10796
+Object *newMacro(newMacro
334,10975
+Object *newPrimitive(newPrimitive
338,11152
+Object *newEnv(newEnv
345,11344
+int streamGetc(384,12712
+Stream *streamSeek(streamSeek
452,14747
+int streamPeek(460,14924
+int readNext(469,15130
+int initialReadNext(480,15347
+int peekForward(491,15584
+int peekNext(498,15760
+int readWhile(502,15831
+Object *readUnary(readUnary
511,16007
+Object *readString(readString
524,16384
+int isSymbolChar(540,16914
+Object *readNumberOrSymbol(readNumberOrSymbol
545,17039
+Object *reverseList(reverseList
577,18007
+Object *readList(readList
590,18207
+Object *readExpr(readExpr
622,19197
+void writeObject(645,19916
+#define CASE(647,20004
+#undef CASE654,20315
+#define CASE(692,21367
+#undef CASE699,21670
+Object *envLookup(envLookup
725,22491
+Object *envAdd(envAdd
740,22848
+Object *envSet(envSet
750,23151
+Object *primitiveSpace(primitiveSpace
772,23735
+Object *primitiveAtom(primitiveAtom
776,23828
+Object *primitiveDif(primitiveDif
794,24412
+Object *primitiveCar(primitiveCar
805,24817
+Object *primitiveCdr(primitiveCdr
817,25126
+Object *primitiveCons(primitiveCons
828,25362
+Object *primitivePrint(primitivePrint
835,25538
+Object *primitivePrinc(primitivePrinc
841,25679
+Object *primitiveNewline(primitiveNewline
847,25821
+Object *primitiveRead(primitiveRead
852,25911
+#define DEFINE_PRIMITIVE_ARITHMETIC(865,26159
+DEFINE_PRIMITIVE_ARITHMETIC(894,27946
+#define DEFINE_PRIMITIVE_RELATIONAL(899,28159
+typedef struct Primitive 925,29771
+  char *name;name
926,29798
+  int nMinArgs,927,29812
+  int nMinArgs, nMaxArgs;927,29812
+  Object *(* eval)928,29838
+} Primitive;929,29883
+Primitive primitives[primitives
931,29897
+  PRIMITIVE_EVAL,969,31590
+  PRIMITIVE_QUOTE,970,31608
+  PRIMITIVE_SAY,971,31627
+  PRIMITIVE_SET,972,31644
+  PRIMITIVE_PROG,973,31661
+  PRIMITIVE_PROGS,974,31679
+  PRIMITIVE_COND,976,31720
+  PRIMITIVE_FILL,977,31738
+  PRIMITIVE_LAMBDA,978,31756
+  PRIMITIVE_MACRO,979,31776
+  PRIMITIVE_TEST980,31795
+Object *evalSet(evalSet
991,32147
+Object *evalProg(evalProg
1017,32877
+Object *progs1(progs1
1031,33198
+Object *evalProgs(evalProgs
1048,33601
+Object *evalCond(evalCond
1072,34218
+Object *evalFill(evalFill
1095,34800
+Object *evalLambda(evalLambda
1118,35382
+Object *evalMacro(evalMacro
1126,35627
+Object *expandMacro(expandMacro
1134,35870
+Object *expandMacroTo(expandMacroTo
1144,36152
+Object *evalList(evalList
1158,36542
+Object *evalExpr(evalExpr
1172,36914
+#define LISP(1249,40130
+static char *stdlib stdlib
1251,40162
+Object *newRootEnv(newRootEnv
1307,41788
diff --git a/work-in-progress/lali.c b/work-in-progress/lali.c
new file mode 100644
index 0000000..e0c0cbb
--- /dev/null
+++ b/work-in-progress/lali.c
@@ -0,0 +1,173 @@
+/*
+ * lali (Lali Another Lisp Implementation)
+ *
+ * Author: Daniel Cerqueira (dan.git@lispclub.com)
+ * Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+ * Version: 0.0
+ * Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+ *           computer programming language
+ * Homepage: https://gitlab.com/alexandre1985/lali
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Copyright (C) 2025 Daniel Cerqueira
+ *
+ * This file is part of lali.
+ *
+ * lali is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, see <https://www.gnu.org/licenses/>.
+ *
+ *
+ * lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/>
+ * version from 2016, written by Matthias Pirstitz, which is released to public
+ * domain under Unlicense <https://unlicense.org/>.
+ */
+
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "liblali.h"
+
+#define YEARS                "2025"
+
+// MAIN ///////////////////////////////////////////////////////////////////////
+
+void runFile(int infd, Object **env, GC_PARAM) {
+  Stream stream = { STREAM_TYPE_FILE, .fd = infd };
+  GC_TRACE(gcObject, nil);
+
+  if (setjmp(exceptionEnv))
+    return;
+
+  // deal with shebang
+  if (peekForward(&stream, true) == EOF)
+    return;
+
+  do {
+    *gcObject = nil;
+    *gcObject = readExpr(&stream, GC_ROOTS);
+    evalExpr(gcObject, env, GC_ROOTS);
+  } while (peekNext(&stream) != EOF);
+}
+
+void runREPL(int infd, Object **env, GC_PARAM) {
+  Stream stream = { STREAM_TYPE_FILE, .fd = infd };
+  GC_TRACE(gcObject, nil);
+
+  for (;;) {
+    if (setjmp(exceptionEnv))
+      continue;
+
+    for (;;) {
+      *gcObject = nil;
+
+      fputs("lali> ", stdout);
+      fflush(stdout);
+
+      if (peekNext(&stream) == EOF) {
+        fputc('\n', stdout);
+        return;
+      }
+
+      *gcObject = readExpr(&stream, GC_ROOTS);
+      *gcObject = evalExpr(gcObject, env, GC_ROOTS);
+
+      writeObject(*gcObject, true, stdout);
+      fputc('\n', stdout);
+    }
+  }
+}
+
+int main(int argc, char *argv[]) {
+  int options = 0;
+  bool repl = false;
+  bool close = false;
+  bool quiet = false;
+
+  if (argc >= 2) {
+    if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
+      fprintf(stderr, "basic usages:\nnormal:        %s [file]...\nclose stdin:   %s -c [file]...\nrun repl:      %s -r [-q] [file]...\n\nin normal mode, reads from standard input.\nwhen present, load file(s) at startup. can be used as library file(s).\n", argv[0], argv[0], argv[0]);
+      return EXIT_SUCCESS;
+    } else if (!strcmp(argv[1], "-c")) {
+      options++;
+      close = true;
+    } else if (!strcmp(argv[1], "-r")) {
+      options++;
+      repl = true;
+      if (argc > 2 && !strcmp(argv[2], "-q")) {
+        options++;
+        quiet = true;
+      }
+    } else if (!strcmp(argv[1], "-q")) {
+      options++;
+      quiet = true;
+      if (argc > 2 && !strcmp(argv[2], "-r")) {
+        options++;
+        repl = true;
+      }
+    } else if (argv[1][0] == '-') {
+      fprintf(stderr, "%s: unrecognized option, `%s'\n", argv[0], argv[1]);
+      return EXIT_FAILURE;
+    }
+  }
+
+  GC_PARAM = nil;
+
+  if (setjmp(exceptionEnv))
+    return EXIT_FAILURE;
+
+  symbols = nil;
+  symbols = newCons(&nil, &symbols, GC_ROOTS);
+  symbols = newCons(&n, &symbols, GC_ROOTS);
+  symbols = newCons(&t, &symbols, GC_ROOTS);
+  symbols = newCons(&f, &symbols, GC_ROOTS);
+
+  GC_TRACE(gcEnv, newRootEnv(GC_ROOTS));
+
+  int fd = 0;
+
+  if (argc > 1) {
+    for (int i = ++options; i < argc; i++) {
+      if ((fd = open(argv[i], O_RDONLY)) == -1) {
+        fprintf(stderr, "%s: open() failed, %s\n", argv[0], strerror(errno));
+        return EXIT_FAILURE;
+      }
+      runFile(fd, gcEnv, GC_ROOTS);
+    }
+  }
+
+  if (repl) {
+    if(!isatty(STDIN_FILENO)) {
+      fprintf(stderr, "%s: repl does not accept piping\n", argv[0]);
+      return EXIT_FAILURE;
+    }
+
+    if (!quiet)
+      fprintf(stdout, "lali Copyright (C) %s Daniel Cerqueira\n\nThis is free software: you are free to change and redistribute it,\nunder certain conditions.\nThis program comes with NO WARRANTY, to the extent permitted by law.\n", YEARS);
+
+    runREPL(STDIN_FILENO, gcEnv, GC_ROOTS);
+  }
+  else if (!close)
+    runFile(STDIN_FILENO, gcEnv, GC_ROOTS);
+
+  return EXIT_SUCCESS;
+}
diff --git a/work-in-progress/liblali.c b/work-in-progress/liblali.c
new file mode 100644
index 0000000..d399822
--- /dev/null
+++ b/work-in-progress/liblali.c
@@ -0,0 +1,1339 @@
+/*
+ * lali (Lali Another Lisp Implementation)
+ *
+ * Author: Daniel Cerqueira (dan.git@lispclub.com)
+ * Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+ * Version: 0.0
+ * Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+ *           computer programming language
+ * Homepage: https://gitlab.com/alexandre1985/lali
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Copyright (C) 2025 Daniel Cerqueira
+ *
+ * This file is part of lali.
+ *
+ * lali is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, see <https://www.gnu.org/licenses/>.
+ *
+ *
+ * lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/>
+ * version from 2016, written by Matthias Pirstitz, which is released to public
+ * domain under Unlicense <https://unlicense.org/>.
+ */
+
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "liblali.h"
+
+#define MEMORY_SIZE          3000000UL
+
+static Memory *memory = &(Memory){ MEMORY_SIZE };
+
+Object *symbols = NULL;
+Object *nil = &(Object){ TYPE_SYMBOL, .string = "()" };
+Object *n = &(Object){ TYPE_SYMBOL, .string = "n" };
+Object *t = &(Object){ TYPE_SYMBOL, .string = "t" };
+Object *f = &(Object){ TYPE_SYMBOL, .string = "f" };
+
+jmp_buf exceptionEnv;
+
+// EXCEPTION HANDLING /////////////////////////////////////////////////////////
+
+void exceptionWithObject(Object *object, char *format, ...) {
+  fputs("error: ", stderr);
+
+  if (object) {
+    writeObject(object, true, stderr);
+    fputc(' ', stderr);
+  }
+
+  va_list args;
+  va_start(args, format);
+  vfprintf(stderr, format, args);
+  va_end(args);
+  fputc('\n', stderr);
+
+  longjmp(exceptionEnv, 1);
+}
+
+// GARBAGE COLLECTION /////////////////////////////////////////////////////////
+
+/* This implements Cheney's copying garbage collector, with which memory is
+ * divided into two equal halves (semispaces): from- and to-space. From-space
+ * is where new objects are allocated, whereas to-space is used during garbage
+ * collection.
+ *
+ * When garbage collection is performed, objects that are still in use (live)
+ * are copied from from-space to to-space. To-space then becomes the new
+ * from-space and vice versa, thereby discarding all objects that have not
+ * been copied.
+ *
+ * Our garbage collector takes as input a list of root objects. Objects that
+ * can be reached by recursively traversing this list are considered live and
+ * will be moved to to-space. When we move an object, we must also update its
+ * pointer within the list to point to the objects new location in memory.
+ *
+ * However, this implies that our interpreter cannot use raw pointers to
+ * objects in any function that might trigger garbage collection (or risk
+ * causing a SEGV when accessing an object that has been moved). Instead,
+ * objects must be added to the list and then only accessed through the
+ * pointer inside the list.
+ *
+ * Thus, whenever we would have used a raw pointer to an object, we use a
+ * pointer to the pointer inside the list instead:
+ *
+ *   function:              pointer to pointer inside list (Object **)
+ *                                  |
+ *                                  v
+ *   list of root objects:  pointer to object (Object *)
+ *                                  |
+ *                                  v
+ *   semispace:             object in memory
+ *
+ * GC_ROOTS and GC_PARAM are used to pass the list from function to function.
+ *
+ * GC_TRACE adds an object to the list and declares a variable which points to
+ * the objects pointer inside the list.
+ *
+ *   GC_TRACE(gcX, X):  add object X to the list and declare Object **gcX
+ *                      to point to the pointer to X inside the list.
+ */
+
+Object *gcMoveObject(Object *object) {
+  // skip object if it is not within from-space (i.e. on the stack)
+  if (object < (Object *)memory->fromSpace ||
+      object >= (Object *)((char *)memory->fromSpace + memory->fromOffset))
+    return object;
+
+  // if the object has already been moved, return its new location
+  if (object->type == (Type)-1)
+    return object->forward;
+
+  // copy object to to-space
+  Object *forward = (Object *)((char *)memory->toSpace + memory->toOffset);
+  memcpy(forward, object, object->size);
+  memory->toOffset += object->size;
+
+  // mark object as moved and set forwarding pointer
+  object->type = (Type)-1;
+  object->forward = forward;
+
+  return object->forward;
+}
+
+void gc(GC_PARAM) {
+  memory->toOffset = 0;
+
+  // move symbols and root objects
+  symbols = gcMoveObject(symbols);
+
+  for (Object *object = GC_ROOTS; object != nil; object = object->cdr)
+    object->car = gcMoveObject(object->car);
+
+  // iterate over objects in to-space and move all objects they reference
+  for (Object *object = memory->toSpace;
+       object < (Object *)((char *)memory->toSpace + memory->toOffset);
+       object = (Object *)((char *)object + object->size)) {
+
+    switch (object->type) {
+    case TYPE_NUMBER:
+    case TYPE_STRING:
+    case TYPE_SYMBOL:
+    case TYPE_PRIMITIVE:
+      break;
+    case TYPE_CONS:
+      object->car = gcMoveObject(object->car);
+      object->cdr = gcMoveObject(object->cdr);
+      break;
+    case TYPE_LAMBDA:
+    case TYPE_MACRO:
+      object->closure = gcMoveObject(object->closure);
+      object->params = gcMoveObject(object->params);
+      object->body = gcMoveObject(object->body);
+      object->env = gcMoveObject(object->env);
+      break;
+    case TYPE_ENV:
+      object->parent = gcMoveObject(object->parent);
+      object->vars = gcMoveObject(object->vars);
+      object->vals = gcMoveObject(object->vals);
+      break;
+    }
+  }
+
+  // swap from- and to-space
+  void *swap = memory->fromSpace;
+  memory->fromSpace = memory->toSpace;
+  memory->toSpace = swap;
+  memory->fromOffset = memory->toOffset;
+}
+
+// MEMORY MANAGEMENT //////////////////////////////////////////////////////////
+
+size_t memoryAlign(size_t size, size_t alignment) {
+  return (size + alignment - 1) & ~(alignment - 1);
+}
+
+Object *memoryAllocObject(Type type, size_t size, GC_PARAM) {
+  size = memoryAlign(size, sizeof (void *));
+
+  // allocate from- and to-space
+  if (!memory->fromSpace) {
+    if (!(memory->fromSpace = mmap(NULL, memory->capacity * 2,
+                                   PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)))
+      exception("mmap() failed, %s", strerror(errno));
+
+    memory->toSpace = (char *)memory->fromSpace + memory->capacity;
+  }
+
+  // run garbage collection if capacity exceeded
+  if (memory->fromOffset + size >= memory->capacity)
+    gc(GC_ROOTS);
+  if (memory->fromOffset + size >= memory->capacity)
+    exception("out of memory, %lu bytes", (unsigned long)size);
+
+  // allocate object in from-space
+  Object *object = (Object *)((char *)memory->fromSpace + memory->fromOffset);
+  object->type = type;
+  object->size = size;
+  memory->fromOffset += size;
+
+  return object;
+}
+
+// CONSTRUCTING OBJECTS ///////////////////////////////////////////////////////
+
+Object *newObject(Type type, GC_PARAM) {
+  return memoryAllocObject(type, sizeof (Object), GC_ROOTS);
+}
+
+Object *newObjectFrom(Object **from, GC_PARAM) {
+  Object *object = memoryAllocObject((*from)->type, (*from)->size, GC_ROOTS);
+  memcpy(object, *from, (*from)->size);
+  return object;
+}
+
+Object *newNumber(double number, GC_PARAM) {
+  Object *object = newObject(TYPE_NUMBER, GC_ROOTS);
+  object->number = number;
+  return object;
+}
+
+Object *newObjectWithString(Type type, size_t size, GC_PARAM) {
+  size = (size > sizeof (((Object *)NULL)->string))
+    ? size - sizeof (((Object *)NULL)->string)
+    : 0;
+  return memoryAllocObject(type, sizeof (Object) + size, GC_ROOTS);
+}
+
+Object *newStringWithLength(char *string, size_t length, GC_PARAM) {
+  int nEscapes = 0;
+
+  for (int i = 1; i < length; ++i)
+    if (string[i - 1] == '\\' && strchr("\\\"trn", string[i]))
+      ++i, ++nEscapes;
+
+  Object *object = newObjectWithString(TYPE_STRING,
+                                       length - nEscapes + 1, GC_ROOTS);
+
+  for (int r = 1, w = 0; r <= length; ++r) {
+    if (string[r - 1] == '\\' && r < length) {
+      switch (string[r]) {
+      case '\\': object->string[w++] = '\\'; r++; break;
+      case '"':  object->string[w++] = '"';  r++; break;
+      case 't':  object->string[w++] = '\t'; r++; break;
+      case 'r':  object->string[w++] = '\r'; r++; break;
+      case 'n':  object->string[w++] = '\n'; r++; break;
+      default:   object->string[w++] = '\\';      break;
+      }
+    } else
+      object->string[w++] = string[r - 1];
+  }
+
+  object->string[length - nEscapes] = '\0';
+  return object;
+}
+
+Object *newString(char *string, GC_PARAM) {
+  return newStringWithLength(string, strlen(string), GC_ROOTS);
+}
+
+Object *newCons(Object **car, Object **cdr, GC_PARAM) {
+  Object *object = newObject(TYPE_CONS, GC_ROOTS);
+  object->car = *car;
+  object->cdr = *cdr;
+  return object;
+}
+
+Object *newSymbolWithLength(char *string, size_t length, GC_PARAM) {
+  for (Object *object = symbols; object != nil; object = object->cdr)
+    if (memcmp(object->car->string, string, length) == 0
+        && object->car->string[length] == '\0')
+      return object->car;
+
+  GC_TRACE(gcObject, newObjectWithString(TYPE_SYMBOL, length + 1, GC_ROOTS));
+  memcpy((*gcObject)->string, string, length);
+  (*gcObject)->string[length] = '\0';
+
+  symbols = newCons(gcObject, &symbols, GC_ROOTS);
+
+  return *gcObject;
+}
+
+Object *newSymbol(char *string, GC_PARAM) {
+  return newSymbolWithLength(string, strlen(string), GC_ROOTS);
+}
+
+Object *newObjectWithClosure(Type type, Object **closure, Object **params, Object **body, Object **env, GC_PARAM) {
+  Object *list;
+
+  for (list = *params; list->type == TYPE_CONS; list = list->cdr) {
+    if (list->car->type != TYPE_SYMBOL)
+      exceptionWithObject(list->car, "is not a symbol");
+    if (list->car == nil || list->car == n || list->car == t || list->car == f)
+      exceptionWithObject(list->car, "cannot be used as a parameter");
+  }
+
+  if (list != nil && list->type != TYPE_SYMBOL)
+    exceptionWithObject(list, "is not a symbol");
+
+  Object *object = newObject(type, GC_ROOTS);
+
+  object->closure = *closure;
+  object->params = *params;
+  object->body = *body;
+  object->env = *env;
+  return object;
+}
+
+Object *newLambda(Object **closure, Object **params, Object **body, Object **env, GC_PARAM) {
+  return newObjectWithClosure(TYPE_LAMBDA, closure, params, body, env, GC_ROOTS);
+}
+
+Object *newMacro(Object **closure, Object **params, Object **body, Object **env, GC_PARAM) {
+  return newObjectWithClosure(TYPE_MACRO, closure, params, body, env, GC_ROOTS);
+}
+
+Object *newPrimitive(int primitive, char *name, GC_PARAM) {
+  Object *object = newObject(TYPE_PRIMITIVE, GC_ROOTS);
+  object->primitive = primitive;
+  object->name = name;
+  return object;
+}
+
+Object *newEnv(Object **func, Object **vals, GC_PARAM) {
+  Object *object = newObject(TYPE_ENV, GC_ROOTS);
+
+  if ((*func) == nil)
+    object->parent = object->vars = object->vals = nil;
+  else {
+    Object *param = (*func)->params, *val = *vals;
+
+    for (int nArgs = 0;; param = param->cdr, val = val->cdr, ++nArgs) {
+      if (param == nil && val == nil)
+        break;
+      else if (param != nil && param->type == TYPE_SYMBOL)
+        break;
+      else if (val != nil && val->type != TYPE_CONS)
+        exceptionWithObject(val, "is not a list");
+      else if (param == nil && val != nil)
+        exceptionWithObject(*func, "expects at most %d arguments", nArgs);
+      else if (param != nil && val == nil) {
+        for (; param->type == TYPE_CONS; param = param->cdr, ++nArgs);
+        exceptionWithObject(*func, "expects at least %d arguments", nArgs);
+      }
+    }
+
+    object->parent = (*func)->env;
+    object->vars = (*func)->params;
+    object->vals = *vals;
+  }
+
+  return object;
+}
+
+// STREAM INPUT ///////////////////////////////////////////////////////////////
+
+/* The purpose of the stream functions is to provide an abstraction over file
+ * and string inputs. In order to accommodate the REPL, we need to be able to
+ * process character special files (such as stdin) character by character and
+ * evaluate expressions as they are being entered.
+ */
+
+int streamGetc(Stream *stream) {
+  if (stream->offset >= stream->length) {
+    switch (stream->type) {
+    case STREAM_TYPE_STRING:
+      // set length if a string was given but its length has not been set
+      if (!stream->length && stream->buffer && *stream->buffer) {
+        stream->length = strlen(stream->buffer);
+        return streamGetc(stream);
+      }
+
+      return EOF;
+
+    case STREAM_TYPE_FILE:
+      // if this is the first read, try to find the size of the file
+      if (!stream->buffer) {
+        struct stat st;
+
+        if (fstat(stream->fd, &st) == -1)
+          exception("fstat() failed, %s", strerror(errno));
+
+        if (S_ISREG(st.st_mode)) {
+          stream->size = st.st_size;
+
+          if (!(stream->buffer = malloc(stream->size)))
+            exception("out of memory, %ld bytes", (long)stream->size);
+
+          stream->capacity = stream->size;
+        } else
+          stream->size = -1;
+      }
+
+      // resize buffer to nearest multiple of BUFSIZ if capacity exceeded
+      if (stream->offset >= stream->capacity) {
+        char *buffer;
+        size_t capacity = stream->offset
+          ? (stream->offset / BUFSIZ + 1) * BUFSIZ
+          : BUFSIZ;
+
+        if (!(buffer = realloc(stream->buffer, capacity)))
+          exception("out of memory, %ld bytes", (long)capacity);
+
+        stream->buffer = buffer;
+        stream->capacity = capacity;
+      }
+
+      // read until offset reached
+      while (stream->length <= stream->offset) {
+        ssize_t nbytes = read(stream->fd, stream->buffer + stream->length,
+                              stream->capacity - stream->length);
+
+        if (nbytes > 0)
+          stream->length += nbytes;
+        else if (nbytes < 0 && errno != EINTR)
+          exception("read() failed, %s", strerror(errno));
+
+        if (nbytes == 0 || stream->length == stream->size) {
+          stream->type = STREAM_TYPE_STRING;
+          return streamGetc(stream);
+        }
+      }
+
+      break;
+    }
+  }
+
+  return (unsigned char)stream->buffer[stream->offset++];
+}
+
+Stream *streamSeek(Stream *stream, int offset) {
+  if (offset < 0 && -offset >= stream->offset)
+    stream->offset = 0;
+  else
+    stream->offset += offset;
+  return stream;
+}
+
+int streamPeek(Stream *stream) {
+  int ch = streamGetc(stream);
+  if (ch != EOF)
+    streamSeek(stream, -1);
+  return ch;
+}
+
+// READING S-EXPRESSIONS //////////////////////////////////////////////////////
+
+int readNext(Stream *stream) {
+  for (;;) {
+    int ch = streamGetc(stream);
+    if (ch == ';')
+      while ((ch = streamGetc(stream)) != EOF && ch != '\n');
+    if (isspace(ch))
+      continue;
+    return ch;
+  }
+}
+
+int initialReadNext(Stream *stream) {
+  for (;;) {
+    int ch = streamGetc(stream);
+    if (ch == ';' || ch == '#')
+      while ((ch = streamGetc(stream)) != EOF && ch != '\n');
+    if (isspace(ch))
+      continue;
+    return ch;
+  }
+}
+
+int peekForward(Stream *stream, bool shebang) {
+  int ch = (shebang) ? initialReadNext(stream) : readNext(stream);
+  if (ch != EOF)
+    streamSeek(stream, -1);
+  return ch;
+}
+
+int peekNext(Stream *stream) {
+  return peekForward(stream, false);
+}
+
+int readWhile(Stream *stream, int (*predicate)(int ch)) {
+  for (;;) {
+    int ch = streamPeek(stream);
+    if (!predicate(ch))
+      return ch;
+    streamGetc(stream);
+  }
+}
+
+Object *readUnary(Stream *stream, char *symbol, GC_PARAM) {
+  if (peekNext(stream) == EOF)
+    exception("unexpected end of stream in %s", symbol);
+
+  GC_TRACE(gcSymbol, newSymbol(symbol, GC_ROOTS));
+  GC_TRACE(gcObject, readExpr(stream, GC_ROOTS));
+
+  *gcObject = newCons(gcObject, &nil, GC_ROOTS);
+  *gcObject = newCons(gcSymbol, gcObject, GC_ROOTS);
+
+  return *gcObject;
+}
+
+Object *readString(Stream *stream, GC_PARAM) {
+  size_t offset = stream->offset;
+
+  for (bool isEscaped = false;;) {
+    int ch = streamGetc(stream);
+    if (ch == EOF)
+      exception("unexpected end of stream in string literal \"%.*s\"",
+                (int)(stream->offset - offset), stream->buffer + offset);
+    if (ch == '"' && !isEscaped)
+      return newStringWithLength(stream->buffer + offset,
+                                 stream->offset - offset - 1, GC_ROOTS);
+
+    isEscaped = (ch == '\\' && !isEscaped);
+  }
+}
+
+int isSymbolChar(int ch) {
+  static const char *valid = "!#$%&*+-./:<=>?@^_~";
+  return isalnum(ch) || strchr(valid, ch);
+}
+
+Object *readNumberOrSymbol(Stream *stream, GC_PARAM) {
+  size_t offset = stream->offset;
+  int ch = streamPeek(stream);
+
+  // skip optional leading sign
+  if (ch == '+' || ch == '-') {
+    streamGetc(stream);
+    ch = streamPeek(stream);
+  }
+
+  // try to read a number in integer or decimal format
+  if (ch == '.' || isdigit(ch)) {
+    if (isdigit(ch))
+      ch = readWhile(stream, isdigit);
+    if (!isSymbolChar(ch))
+      return newNumber(strtol(stream->buffer + offset, NULL, 10), GC_ROOTS);
+    if (ch == '.') {
+      ch = streamGetc(stream);
+      if (isdigit(streamPeek(stream))) {
+        ch = readWhile(stream, isdigit);
+        if (!isSymbolChar(ch))
+          return newNumber(strtod(stream->buffer + offset, NULL), GC_ROOTS);
+      }
+    }
+  }
+
+  // non-numeric character encountered, read a symbol
+  readWhile(stream, isSymbolChar);
+  return newSymbolWithLength(stream->buffer + offset,
+                             stream->offset - offset, GC_ROOTS);
+}
+
+Object *reverseList(Object *list) {
+  Object *object = nil;
+
+  while (list != nil) {
+    Object *swap = list;
+    list = list->cdr;
+    swap->cdr = object;
+    object = swap;
+  }
+
+  return object;
+}
+
+Object *readList(Stream *stream, GC_PARAM) {
+  GC_TRACE(gcList, nil);
+  GC_TRACE(gcLast, nil);
+
+  for (;;) {
+    int ch = readNext(stream);
+    if (ch == EOF)
+      exception("unexpected end of stream in list");
+    else if (ch == ')')
+      return reverseList(*gcList);
+    else if (ch == '.' && !isSymbolChar(streamPeek(stream))) {
+      if (*gcLast == nil)
+        exception("unexpected dot at start of list");
+      if ((ch = peekNext(stream)) == ')')
+        exception("expected object at end of dotted list");
+      if (!(*gcLast = readExpr(stream, GC_ROOTS)))
+        exception("unexpected end of stream in dotted list");
+      if ((ch = peekNext(stream)) != ')')
+        exception("unexpected object at end of dotted list");
+
+      readNext(stream);
+      Object *list = reverseList(*gcList);
+      (*gcList)->cdr = *gcLast;
+
+      return list;
+    } else {
+      *gcLast = readExpr(streamSeek(stream, -1), GC_ROOTS);
+      *gcList = newCons(gcLast, gcList, GC_ROOTS);
+    }
+  }
+}
+
+Object *readExpr(Stream *stream, GC_PARAM) {
+  for (;;) {
+    int ch = readNext(stream);
+    if (ch == EOF)
+      return NULL;
+    else if (ch == '\'')
+      return readUnary(stream, "quote", GC_ROOTS);
+    else if (ch == '\\')
+      return readUnary(stream, "say", GC_ROOTS);
+    else if (ch == '"')
+      return readString(stream, GC_ROOTS);
+    else if (ch == '(')
+      return readList(stream, GC_ROOTS);
+    else if (isSymbolChar(ch)
+             && (ch != '.' || isSymbolChar(streamPeek(stream))))
+      return readNumberOrSymbol(streamSeek(stream, -1), GC_ROOTS);
+    else
+      exception("unexpected character, `%c'", ch);
+  }
+}
+
+// WRITING OBJECTS ////////////////////////////////////////////////////////////
+
+void writeObject(Object *object, bool readably, FILE *file) {
+  switch (object->type) {
+#define CASE(type, ...)                         \
+    case type:                                  \
+      fprintf(file, __VA_ARGS__);               \
+      break
+    CASE(TYPE_NUMBER, "%g", object->number);
+    CASE(TYPE_SYMBOL, "%s", object->string);
+    CASE(TYPE_PRIMITIVE, "#<Primitive %s>", object->name);
+#undef CASE
+  case TYPE_STRING:
+    if (readably) {
+      fputc('"', file);
+      for (char *string = object->string; *string; ++string) {
+        switch (*string) {
+        case '"':  fputs("\\\"",  file); break;
+        case '\t': fputs("\\t",   file); break;
+        case '\r': fputs("\\r",   file); break;
+        case '\n': fputs("\\n",   file); break;
+        case '\\': fputs("\\\\",  file); break;
+        default:   fputc(*string, file); break;
+        }
+      }
+      fputc('"', file);
+    } else
+      fprintf(file, "%s", object->string);
+    break;
+  case TYPE_CONS:
+  case TYPE_LAMBDA:
+  case TYPE_MACRO:
+    if (readably)
+      fputc('(', file);
+    writeObject(object->car, readably, file);
+    while (object->cdr != nil) {
+      object = object->cdr;
+      if (object->type == TYPE_CONS) {
+        fputc(' ', file);
+        writeObject(object->car, readably, file);
+      } else {
+        fputs(" . ", file);
+        writeObject(object, readably, file);
+        break;
+      }
+    }
+    if (readably)
+      fputc(')', file);
+    break;
+#define CASE(type, name, object)                \
+    case type:                                  \
+      fprintf(file, "#<%s ", name);             \
+      writeObject(object, readably, file);      \
+      fprintf(file, ">");                       \
+      break
+    CASE(TYPE_ENV, "Env", object->vars);
+#undef CASE
+  }
+}
+
+// ENVIRONMENT ////////////////////////////////////////////////////////////////
+
+/* An environment consists of a pointer to its parent environment (if any) and
+ * two parallel lists - vars and vals.
+ *
+ * Case 1 - vars is a regular list:
+ *   vars: (a b c), vals: (1 2 3)        ; a = 1, b = 2, c = 3
+ *
+ * Case 2 - vars is a dotted list:
+ *   vars: (a b . c), vals: (1 2)        ; a = 1, b = 2, c = nil
+ *   vars: (a b . c), vals: (1 2 3)      ; a = 1, b = 2, c = (3)
+ *   vars: (a b . c), vals: (1 2 3 4 5)  ; a = 1, b = 2, c = (3 4 5)
+ *
+ * Case 3 - vars is a symbol:
+ *   vars: a, vals: nil                  ; a = nil
+ *   vars: a, vals: (1)                  ; a = (1)
+ *   vars: a, vals: (1 2 3)              ; a = (1 2 3)
+ *
+ * Case 4 - vars and vals are both nil:
+ *   vars: nil, vals: nil
+ */
+
+Object *envLookup(Object *var, Object *env) {
+  for (; env != nil; env = env->parent) {
+    Object *vars = env->vars, *vals = env->vals;
+
+    for (; vars->type == TYPE_CONS; vars = vars->cdr, vals = vals->cdr)
+      if (vars->car == var)
+        return vals->car;
+
+    if (vars == var)
+      return vals;
+  }
+
+  exceptionWithObject(var, "has no value");
+}
+
+Object *envAdd(Object **var, Object **val, Object **env, GC_PARAM) {
+  GC_TRACE(gcVars, newCons(var, &nil, GC_ROOTS));
+  GC_TRACE(gcVals, newCons(val, &nil, GC_ROOTS));
+
+  (*gcVars)->cdr = (*env)->vars, (*env)->vars = *gcVars;
+  (*gcVals)->cdr = (*env)->vals, (*env)->vals = *gcVals;
+
+  return *val;
+}
+
+Object *envSet(Object **var, Object **val, Object **env, GC_PARAM) {
+  GC_TRACE(gcEnv, *env);
+
+  for (;;) {
+    Object *vars = (*gcEnv)->vars, *vals = (*gcEnv)->vals;
+
+    for (; vars->type == TYPE_CONS; vars = vars->cdr, vals = vals->cdr) {
+      if (vars->car == *var)
+        return vals->car = *val;
+      if (vars->cdr == *var)
+        return vals->cdr = *val;
+    }
+
+    if ((*gcEnv)->parent == nil)
+      return envAdd(var, val, gcEnv, GC_ROOTS);
+    else
+      *gcEnv = (*gcEnv)->parent;
+  }
+}
+
+// PRIMITIVES /////////////////////////////////////////////////////////////////
+
+Object *primitiveSpace(Object **args, GC_PARAM) {
+  return ((*args)->car == nil) ? t : f;
+}
+
+Object *primitiveAtom(Object **args, GC_PARAM) {
+  Object *first = (*args)->car;
+
+  return (first != nil && first->type != TYPE_CONS) ? t : f;
+}
+
+/* Object *primitiveEq(Object **args, GC_PARAM) {
+ *   Object *first = (*args)->car, *second = (*args)->cdr->car;
+ *
+ *   if (first->type == TYPE_NUMBER && second->type == TYPE_NUMBER)
+ *     return (first->number == second->number) ? t : f;
+ *   else if (first->type == TYPE_STRING && second->type == TYPE_STRING)
+ *     return !strcmp(first->string, second->string) ? t : f;
+ *   else
+ *     return (first == second) ? t : f;
+ * }
+ */
+
+Object *primitiveDif(Object **args, GC_PARAM) {
+  Object *first = (*args)->car, *second = (*args)->cdr->car;
+
+  if (first->type == TYPE_NUMBER && second->type == TYPE_NUMBER)
+    return (first->number != second->number) ? t : f;
+  else if (first->type == TYPE_STRING && second->type == TYPE_STRING)
+    return strcmp(first->string, second->string) ? t : f;
+  else
+    return (first != second) ? t : f;
+}
+
+Object *primitiveCar(Object **args, GC_PARAM) {
+  Object *first = (*args)->car;
+
+  if (first == nil)
+    return nil;
+  /* else if (first->type == TYPE_CONS || first->type == TYPE_LAMBDA) */
+  else if (first->type == TYPE_CONS)
+    return first->car;
+  else
+    exceptionWithObject(first, "is not a list");
+}
+
+Object *primitiveCdr(Object **args, GC_PARAM) {
+  Object *first = (*args)->car;
+
+  if (first == nil)
+    return nil;
+  else if (first->type == TYPE_CONS)
+    return first->cdr;
+  else
+    exceptionWithObject(first, "is not a list");
+}
+
+Object *primitiveCons(Object **args, GC_PARAM) {
+  GC_TRACE(gcFirst, (*args)->car);
+  GC_TRACE(gcSecond, (*args)->cdr->car);
+
+  return newCons(gcFirst, gcSecond, GC_ROOTS);
+}
+
+Object *primitivePrint(Object **args, GC_PARAM) {
+  writeObject((*args)->car, true, stdout);
+  fputc(' ', stdout);
+  return (*args)->car;
+}
+
+Object *primitivePrinc(Object **args, GC_PARAM) {
+  writeObject((*args)->car, false, stdout);
+  fputc(' ', stdout);
+  return (*args)->car;
+}
+
+Object *primitiveNewline(Object **args, GC_PARAM) {
+  fputc('\n', stdout);
+  return n;
+}
+
+Object *primitiveRead(Object **args, GC_PARAM) {
+  Stream stream = { STREAM_TYPE_FILE, .fd = STDIN_FILENO };
+
+  fflush(stdout);
+
+  if (peekNext(&stream) == EOF) {
+    fputc('\n', stdout);
+    return n;
+  }
+
+  return readExpr(&stream, GC_ROOTS);
+}
+
+#define DEFINE_PRIMITIVE_ARITHMETIC(name, op, init)             \
+  Object *name(Object **args, GC_PARAM) {                       \
+    if (*args == nil)                                           \
+      return newNumber(init, GC_ROOTS);                         \
+    else if ((*args)->car->type != TYPE_NUMBER)                 \
+      exceptionWithObject((*args)->car, "is not a number");     \
+    else {                                                      \
+      Object *object, *rest;                                    \
+                                                                \
+      if ((*args)->cdr == nil) {                                \
+        object = newNumber(init, GC_ROOTS);                     \
+        rest = *args;                                           \
+      } else {                                                  \
+        GC_TRACE(gcFirst, (*args)->car);                        \
+        object = newObjectFrom(gcFirst, GC_ROOTS);              \
+        rest = (*args)->cdr;                                    \
+      }                                                         \
+                                                                \
+      for (; rest != nil; rest = rest->cdr) {                   \
+        if (rest->car->type != TYPE_NUMBER)                     \
+          exceptionWithObject(rest->car, "is not a number");    \
+                                                                \
+        object->number = object->number op rest->car->number;   \
+      }                                                         \
+                                                                \
+      return object;                                            \
+    }                                                           \
+  }
+
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveAdd,      +, 0)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveSubtract, -, 0)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveMultiply, *, 1)
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveDivide,   /, 1)
+
+#define DEFINE_PRIMITIVE_RELATIONAL(name, op)                           \
+  Object *name(Object **args, GC_PARAM) {                               \
+    if ((*args)->car->type != TYPE_NUMBER)                              \
+      exceptionWithObject((*args)->car, "is not a number");             \
+    else {                                                              \
+      Object *rest = *args;                                             \
+      bool result = true;                                               \
+                                                                        \
+      for (; result && rest->cdr != nil; rest = rest->cdr) {            \
+        if (rest->cdr->car->type != TYPE_NUMBER)                        \
+          exceptionWithObject(rest->cdr->car, "is not a number");       \
+                                                                        \
+        result &= rest->car->number op rest->cdr->car->number;          \
+      }                                                                 \
+                                                                        \
+      return result ? t : f;                                            \
+    }                                                                   \
+  }
+
+/* DEFINE_PRIMITIVE_RELATIONAL(primitiveEqual,        ==) */
+DEFINE_PRIMITIVE_RELATIONAL(primitiveDifferent,    !=)
+DEFINE_PRIMITIVE_RELATIONAL(primitiveLess,         < )
+/* DEFINE_PRIMITIVE_RELATIONAL(primitiveLessEqual,    <=) */
+DEFINE_PRIMITIVE_RELATIONAL(primitiveGreater,      > )
+/* DEFINE_PRIMITIVE_RELATIONAL(primitiveGreaterEqual, >=) */
+
+typedef struct Primitive {
+  char *name;
+  int nMinArgs, nMaxArgs;
+  Object *(* eval)(Object **args, GC_PARAM);
+} Primitive;
+
+Primitive primitives[] = {
+  { "eval",    1,  1  /* special form */    },
+  { "quote",   1,  1  /* special form */    },
+  { "say",     1,  1  /* special form */    },
+  { "set",     0, -2  /* special form */    },
+  { "prog",    0, -1  /* special form */    },
+  { "progs",   1, -1  /* special form */    },
+  /* { "if",      2,  3  /\* special form *\/    }, */
+  { "cond",    0, -1  /* special form */    },
+  { "fill",    0, -1  /* special form */    },
+  { "lambda",  1, -1  /* special form */    },
+  { "macro",   1, -1  /* special form */    },
+  { "test",    0, -1  /* special form */    },
+  { "space",   1,  1, primitiveSpace        },
+  { "atom",    1,  1, primitiveAtom         },
+  /* { "eq",      2,  2, primitiveEq           }, */
+  { "dif",     2,  2, primitiveDif          },
+  { "car",     1,  1, primitiveCar          },
+  { "cdr",     1,  1, primitiveCdr          },
+  { "cons",    2,  2, primitiveCons         },
+  { "print",   1,  1, primitivePrint        },
+  { "princ",   1,  1, primitivePrinc        },
+  { "newline", 0,  0, primitiveNewline      },
+  { "read",    0,  0, primitiveRead         },
+  { "+",       0, -1, primitiveAdd          },
+  { "-",       1, -1, primitiveSubtract     },
+  { "*",       0, -1, primitiveMultiply     },
+  { "/",       1, -1, primitiveDivide       },
+  /* { "=",       1, -1, primitiveEqual        }, */
+  { "!",       1, -1, primitiveDifferent    },
+  { "<",       1, -1, primitiveLess         },
+  /* { "<=",      1, -1, primitiveLessEqual    }, */
+  { ">",       1, -1, primitiveGreater      }
+  /* { ">=",      1, -1, primitiveGreaterEqual } */
+};
+
+// Special forms handled by evalExpr. Must be in the same order as above.
+enum {
+  PRIMITIVE_EVAL,
+  PRIMITIVE_QUOTE,
+  PRIMITIVE_SAY,
+  PRIMITIVE_SET,
+  PRIMITIVE_PROG,
+  PRIMITIVE_PROGS,
+  /* PRIMITIVE_IF, */
+  PRIMITIVE_COND,
+  PRIMITIVE_FILL,
+  PRIMITIVE_LAMBDA,
+  PRIMITIVE_MACRO,
+  PRIMITIVE_TEST
+};
+
+// EVALUATION /////////////////////////////////////////////////////////////////
+
+/* Scheme-style tail recursive evaluation. evalProg, evalProgs, evalCond, and
+ * PRIMITIVE_EVAL, return the object in the tail recursive position to be
+ * evaluated by evalExpr. Macros are expanded in-place the first time they are
+ * evaluated.
+ */
+
+Object *evalSet(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else {
+    GC_TRACE(gcVar, (*args)->car);
+    GC_TRACE(gcVal, (*args)->cdr->car);
+
+    *gcVar = evalExpr(gcVar, env, GC_ROOTS);
+
+    if (*gcVar == nil || *gcVar == n || *gcVar == t || *gcVar == f)
+      exceptionWithObject(*gcVar, "is a constant and cannot be set");
+    else if ((*gcVar)->type != TYPE_SYMBOL)
+      exceptionWithObject(*gcVar, "is not an atom and cannot be set");
+
+    *gcVal = evalExpr(gcVal, env, GC_ROOTS);
+    envSet(gcVar, gcVal, env, GC_ROOTS);
+
+    if ((*args)->cdr->cdr == nil)
+      return *gcVal;
+    else {
+      GC_TRACE(gcArgs, (*args)->cdr->cdr);
+      return evalSet(gcArgs, env, GC_ROOTS);
+    }
+  }
+}
+
+Object *evalProg(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else if ((*args)->cdr == nil)
+    return (*args)->car;
+  else {
+    GC_TRACE(gcObject, (*args)->car);
+    GC_TRACE(gcCdr, (*args)->cdr);
+
+    evalExpr(gcObject, env, GC_ROOTS);
+    return evalProg(gcCdr, env, GC_ROOTS);
+  }
+}
+
+Object *progs1(Object **stop, Object **body, Object **env, GC_PARAM) {
+  if (*body == nil)
+    return *stop;
+  else if ((*body)->cdr == nil)
+    return (*body)->car;
+  else {
+    GC_TRACE(gcObject, (*body)->car);
+    GC_TRACE(gcCdr, (*body)->cdr);
+
+    *gcObject = evalExpr(gcObject, env, GC_ROOTS);
+    if (*gcObject == *stop)
+      return *stop;
+
+    return progs1(stop, gcCdr, env, GC_ROOTS);
+  }
+}
+
+Object *evalProgs(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcStop, (*args)->car);
+  GC_TRACE(gcBody, (*args)->cdr);
+
+  *gcStop = evalExpr(gcStop, env, GC_ROOTS);
+
+  if ((*gcStop)->type != TYPE_SYMBOL)
+    exceptionWithObject(*gcStop, "is not a symbol");
+
+  return progs1(gcStop, gcBody, env, GC_ROOTS);
+}
+
+/* Object *evalIf(Object **args, Object **env, GC_PARAM) {
+ *   GC_TRACE(gcObject, (*args)->car);
+ *
+ *   if (evalExpr(gcObject, env, GC_ROOTS) != nil)
+ *     return (*args)->cdr->car;
+ *   else if ((*args)->cdr->cdr != nil)
+ *     return (*args)->cdr->cdr->car;
+ *   else
+ *     return n;
+ * }
+ */
+
+Object *evalCond(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else if ((*args)->car->type != TYPE_CONS)
+    exceptionWithObject((*args)->car, "is not a list");
+  else {
+    GC_TRACE(gcCar, (*args)->car->car);
+    GC_TRACE(gcCdr, (*args)->car->cdr);
+
+    if (*gcCdr == nil) return *gcCar;
+
+    *gcCar = evalExpr(gcCar, env, GC_ROOTS);
+    if (*gcCar == n)
+      return n;
+    else if (*gcCar != f)
+      return evalProg(gcCdr, env, GC_ROOTS);
+    else {
+      GC_TRACE(gcArgs, (*args)->cdr);
+      return evalCond(gcArgs, env, GC_ROOTS);
+    }
+  }
+}
+
+Object *evalFill(Object **args, Object **env, GC_PARAM) {
+  if (*args == nil)
+    return n;
+  else if ((*args)->car->type != TYPE_CONS)
+    exceptionWithObject((*args)->car, "is not a list");
+  else {
+    GC_TRACE(gcCar, (*args)->car->car);
+    GC_TRACE(gcCdr, (*args)->car->cdr);
+
+    if (*gcCdr == nil) return *gcCar;
+
+    *gcCar = evalExpr(gcCar, env, GC_ROOTS);
+    if (*gcCar == n)
+      return n;
+    else if (*gcCar == f)
+      return evalProg(gcCdr, env, GC_ROOTS);
+    else {
+      GC_TRACE(gcArgs, (*args)->cdr);
+      return evalFill(gcArgs, env, GC_ROOTS);
+    }
+  }
+}
+
+Object *evalLambda(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcClosure, (*args)->car);
+  GC_TRACE(gcParams, (*args)->cdr->car);
+  GC_TRACE(gcBody, (*args)->cdr->cdr);
+
+  return newLambda(gcClosure, gcParams, gcBody, env, GC_ROOTS);
+}
+
+Object *evalMacro(Object **args, Object **env, GC_PARAM) {
+  GC_TRACE(gcClosure, (*args)->car);
+  GC_TRACE(gcParams, (*args)->cdr->car);
+  GC_TRACE(gcBody, (*args)->cdr->cdr);
+
+  return newMacro(gcClosure, gcParams, gcBody, env, GC_ROOTS);
+}
+
+Object *expandMacro(Object **macro, Object **args, GC_PARAM) {
+  GC_TRACE(gcEnv, newEnv(macro, args, GC_ROOTS));
+  GC_TRACE(gcBody, (*macro)->body);
+
+  GC_TRACE(gcObject, evalProg(gcBody, gcEnv, GC_ROOTS));
+  *gcObject = evalExpr(gcObject, gcEnv, GC_ROOTS);
+
+  return *gcObject;
+}
+
+Object *expandMacroTo(Object **macro, Object **args, Object **cons, GC_PARAM) {
+  GC_TRACE(gcObject, expandMacro(macro, args, GC_ROOTS));
+
+  if ((*gcObject)->type == TYPE_CONS) {
+    (*cons)->car = (*gcObject)->car;
+    (*cons)->cdr = (*gcObject)->cdr;
+  } else {
+    (*cons)->car = newSymbol("prog", GC_ROOTS);
+    (*cons)->cdr = newCons(gcObject, &nil, GC_ROOTS);
+  }
+
+  return *cons;
+}
+
+Object *evalList(Object **args, Object **env, GC_PARAM) {
+  if ((*args)->type != TYPE_CONS)
+    return evalExpr(args, env, GC_ROOTS);
+  else {
+    GC_TRACE(gcObject, (*args)->car);
+    GC_TRACE(gcArgs, (*args)->cdr);
+
+    *gcObject = evalExpr(gcObject, env, GC_ROOTS);
+    *gcArgs = evalList(gcArgs, env, GC_ROOTS);
+
+    return newCons(gcObject, gcArgs, GC_ROOTS);
+  }
+}
+
+Object *evalExpr(Object **object, Object **env, GC_PARAM) {
+  GC_TRACE(gcObject, *object);
+  GC_TRACE(gcEnv, *env);
+
+  GC_TRACE(gcFunc, nil);
+  GC_TRACE(gcArgs, nil);
+  GC_TRACE(gcBody, nil);
+
+  for (;;) {
+    if ((*gcObject)->type == TYPE_SYMBOL)
+      return envLookup(*gcObject, *gcEnv);
+    if ((*gcObject)->type != TYPE_CONS)
+      return *gcObject;
+
+    *gcFunc = (*gcObject)->car;
+    *gcArgs = (*gcObject)->cdr;
+
+    *gcFunc = evalExpr(gcFunc, gcEnv, GC_ROOTS);
+    *gcBody = nil;
+
+    if ((*gcFunc)->type == TYPE_LAMBDA) {
+      *gcBody = (*gcFunc)->body;
+      *gcArgs = evalList(gcArgs, gcEnv, GC_ROOTS);
+      *gcEnv = newEnv(gcFunc, gcArgs, GC_ROOTS);
+      *gcObject = evalProg(gcBody, gcEnv, GC_ROOTS);
+    } else if ((*gcFunc)->type == TYPE_MACRO) {
+      *gcObject = expandMacroTo(gcFunc, gcArgs, gcObject, GC_ROOTS);
+    } else if ((*gcFunc)->type == TYPE_PRIMITIVE) {
+      Primitive *primitive = &primitives[(*gcFunc)->primitive];
+      int nArgs = 0;
+
+      for (Object *args = *gcArgs; args != nil; args = args->cdr, nArgs++)
+        if (args->type != TYPE_CONS)
+          exceptionWithObject(args, "is not a list");
+
+      if (nArgs < primitive->nMinArgs)
+        exceptionWithObject(*gcFunc, "expects at least %d arguments",
+                            primitive->nMinArgs);
+      if (nArgs > primitive->nMaxArgs && primitive->nMaxArgs >= 0)
+        exceptionWithObject(*gcFunc, "expects at most %d arguments",
+                            primitive->nMaxArgs);
+      if (primitive->nMaxArgs < 0 && nArgs % -primitive->nMaxArgs)
+        exceptionWithObject(*gcFunc, "expects a multiple of %d arguments",
+                            -primitive->nMaxArgs);
+
+      switch ((*gcFunc)->primitive) {
+      case PRIMITIVE_EVAL:   *gcArgs = (*gcArgs)->car;
+                             *gcObject = evalExpr(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_QUOTE:  return (*gcArgs)->car;
+      case PRIMITIVE_SAY:    *gcArgs = (*gcArgs)->car;
+                             return newCons(&nil, gcArgs, GC_ROOTS);
+      case PRIMITIVE_SET:    return evalSet(gcArgs, gcEnv, GC_ROOTS);
+      case PRIMITIVE_PROG:   *gcObject = evalProg(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_PROGS:  *gcObject = evalProgs(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+        /* case PRIMITIVE_IF:     *gcObject = evalIf(gcArgs, gcEnv, GC_ROOTS);
+         *                        break;
+         */
+      case PRIMITIVE_COND:   *gcObject = evalCond(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_FILL:   *gcObject = evalFill(gcArgs, gcEnv, GC_ROOTS);
+                             break;
+      case PRIMITIVE_LAMBDA: return evalLambda(gcObject, gcEnv, GC_ROOTS);
+      case PRIMITIVE_MACRO:  return evalMacro(gcObject, gcEnv, GC_ROOTS);
+      case PRIMITIVE_TEST:   return *gcObject;
+      default:               *gcArgs = evalList(gcArgs, gcEnv, GC_ROOTS);
+                             return primitive->eval(gcArgs, GC_ROOTS);
+      }
+    } else
+      exceptionWithObject(*gcFunc, "is not a function");
+  }
+}
+
+// STANDARD LIBRARY ///////////////////////////////////////////////////////////
+
+#define LISP(...) #__VA_ARGS__
+
+static char *stdlib = LISP(
+  (set (quote list) (lambda args args))
+
+  (set (quote defmacro) (macro (name params . body)
+    (list (quote set) (list quote name) (list (quote macro) params . body))))
+
+  (defmacro defun (name params . body)
+    (list (quote set) (list quote name) (list (quote lambda) params . body)))
+
+  (defun not (x) (fill ((dif x n) n)
+                       (x t)
+                       (f f)))
+
+  (defun ap (x) (not (space x)))
+
+  (defun listp (x) (not (atom x)))
+
+  (defun zerop (x) (not (! x 0)))
+
+  (defmacro and args
+    (fill ((ap args) t)
+          ((ap (cdr args)) (car args))
+          (f (list (quote fill)
+                   (list (list (quote not) (car args))
+                         (cons (quote and) (cdr args)))
+                   (list (quote f) (quote f))))))
+
+  (defun map (func xs)
+    (fill ((ap xs) ())
+          (f (cons (func (car xs)) (map func (cdr xs))))))
+
+  (defmacro or args
+    (fill ((ap args) f)
+          (f (cons (quote fill)
+                   (append (map (lambda (x) (list (list (quote not) x) x))
+                                args)
+                           (list (list f f)))))))
+
+  (defun consp (x) (and (listp x) (ap x)))
+
+  (defun differ (x y)
+    (fill ((or (consp x) (consp y)) (dif x y))
+          (f (or (differ (car x) (car y))
+                 (differ (cdr x) (cdr y))))))
+
+  (defun nth (num xs)
+    (fill ((dif num 0) (car xs))
+          (f (nth (- num 1) (cdr xs)))))
+
+  (defun append (xs y)
+    (fill ((ap xs) y)
+          (f (cons (car xs) (append (cdr xs) y)))))
+);
+
+// MAIN ///////////////////////////////////////////////////////////////////////
+
+Object *newRootEnv(GC_PARAM) {
+  GC_TRACE(gcEnv, newEnv(&nil, &nil, GC_ROOTS));
+  GC_TRACE(gcVar, nil);
+  GC_TRACE(gcVal, nil);
+
+  // add constants
+  envSet(&nil, &nil, gcEnv, GC_ROOTS);
+  envSet(&n, &n, gcEnv, GC_ROOTS);
+  envSet(&t, &t, gcEnv, GC_ROOTS);
+  envSet(&f, &f, gcEnv, GC_ROOTS);
+
+  // add primitives
+  int nPrimitives = sizeof (primitives) / sizeof (primitives[0]);
+
+  for (int i = 0; i < nPrimitives; ++i) {
+    *gcVar = newSymbol(primitives[i].name, GC_ROOTS);
+    *gcVal = newPrimitive(i, primitives[i].name, GC_ROOTS);
+
+    envSet(gcVar, gcVal, gcEnv, GC_ROOTS);
+  }
+
+  // add standard library
+  Stream stream = { STREAM_TYPE_STRING, .buffer = stdlib };
+  GC_TRACE(gcObject, nil);
+
+  while (peekNext(&stream) != EOF) {
+    *gcObject = nil;
+    *gcObject = readExpr(&stream, GC_ROOTS);
+    evalExpr(gcObject, gcEnv, GC_ROOTS);
+  }
+
+  return *gcEnv;
+}
diff --git a/work-in-progress/liblali.h b/work-in-progress/liblali.h
new file mode 100644
index 0000000..026036a
--- /dev/null
+++ b/work-in-progress/liblali.h
@@ -0,0 +1,337 @@
+/*
+ * lali (Lali Another Lisp Implementation)
+ *
+ * Author: Daniel Cerqueira (dan.git@lispclub.com)
+ * Maintainer: Daniel Cerqueira (dan.git@lispclub.com)
+ * Version: 0.0
+ * Keywords: lali, lisp, implementation, interpreter, lisp1.5,
+ *           computer programming language
+ * Homepage: https://gitlab.com/alexandre1985/lali
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Copyright (C) 2025 Daniel Cerqueira
+ *
+ * This file is part of lali.
+ *
+ * lali is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, see <https://www.gnu.org/licenses/>.
+ *
+ *
+ * lali software is based on tiny-lisp <https://github.com/matp/tiny-lisp/>
+ * version from 2016, written by Matthias Pirstitz, which is released to public
+ * domain under Unlicense <https://unlicense.org/>.
+ */
+
+#ifndef LIBLALI_H
+#define LIBLALI_H
+
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+#define MAP_ANONYMOUS        MAP_ANON
+#endif
+
+typedef struct Object Object;
+
+typedef enum Type {
+  TYPE_NUMBER,
+  TYPE_STRING,
+  TYPE_SYMBOL,
+  TYPE_CONS,
+  TYPE_LAMBDA,
+  TYPE_MACRO,
+  TYPE_PRIMITIVE,
+  TYPE_ENV
+} Type;
+
+struct Object {
+  Type type;
+  size_t size;
+  union {
+    struct { double number; };                      // number
+    struct { char string[sizeof (Object *[3])]; };  // string, symbol
+    struct { Object *car, *cdr; };                  // cons
+    struct { Object *closure, *params, *body, *env; }; // lambda, macro
+    struct { int primitive; char *name; };          // primitive
+    struct { Object *parent, *vars, *vals; };       // env
+    struct { Object *forward; };                    // forwarding pointer
+  };
+};
+
+extern Object *symbols;
+extern Object *nil;
+extern Object *n;
+extern Object *t;
+extern Object *f;
+
+typedef enum StreamType {
+  STREAM_TYPE_STRING,
+  STREAM_TYPE_FILE
+} StreamType;
+
+typedef struct Stream {
+  StreamType type;
+  char *buffer;
+  int fd;
+  size_t length, capacity;
+  off_t offset, size;
+} Stream;
+
+typedef struct Memory {
+  size_t capacity, fromOffset, toOffset;
+  void *fromSpace, *toSpace;
+} Memory;
+
+extern jmp_buf exceptionEnv;
+
+// EXCEPTION HANDLING /////////////////////////////////////////////////////////
+
+#define exception(...)       exceptionWithObject(NULL, __VA_ARGS__)
+
+#ifdef __GNUC__
+void exceptionWithObject(Object *object, char *format, ...)
+  __attribute__ ((noreturn, format(printf, 2, 3)));
+#endif
+
+void exceptionWithObject(Object *object, char *format, ...);
+
+// GARBAGE COLLECTION /////////////////////////////////////////////////////////
+
+/* This implements Cheney's copying garbage collector, with which memory is
+ * divided into two equal halves (semispaces): from- and to-space. From-space
+ * is where new objects are allocated, whereas to-space is used during garbage
+ * collection.
+ *
+ * When garbage collection is performed, objects that are still in use (live)
+ * are copied from from-space to to-space. To-space then becomes the new
+ * from-space and vice versa, thereby discarding all objects that have not
+ * been copied.
+ *
+ * Our garbage collector takes as input a list of root objects. Objects that
+ * can be reached by recursively traversing this list are considered live and
+ * will be moved to to-space. When we move an object, we must also update its
+ * pointer within the list to point to the objects new location in memory.
+ *
+ * However, this implies that our interpreter cannot use raw pointers to
+ * objects in any function that might trigger garbage collection (or risk
+ * causing a SEGV when accessing an object that has been moved). Instead,
+ * objects must be added to the list and then only accessed through the
+ * pointer inside the list.
+ *
+ * Thus, whenever we would have used a raw pointer to an object, we use a
+ * pointer to the pointer inside the list instead:
+ *
+ *   function:              pointer to pointer inside list (Object **)
+ *                                  |
+ *                                  v
+ *   list of root objects:  pointer to object (Object *)
+ *                                  |
+ *                                  v
+ *   semispace:             object in memory
+ *
+ * GC_ROOTS and GC_PARAM are used to pass the list from function to function.
+ *
+ * GC_TRACE adds an object to the list and declares a variable which points to
+ * the objects pointer inside the list.
+ *
+ *   GC_TRACE(gcX, X):  add object X to the list and declare Object **gcX
+ *                      to point to the pointer to X inside the list.
+ */
+
+#define GC_ROOTS             gcRoots
+#define GC_PARAM             Object *GC_ROOTS
+
+#define GC_PASTE1(name, id)  name ## id
+#define GC_PASTE2(name, id)  GC_PASTE1(name, id)
+#define GC_UNIQUE(name)      GC_PASTE2(name, __LINE__)
+
+#define GC_TRACE(name, init)                                                     \
+  Object GC_UNIQUE(GC_ROOTS) = { TYPE_CONS, .car = init, .cdr = GC_ROOTS };      \
+  Object **name = &GC_UNIQUE(GC_ROOTS).car;                                      \
+  GC_ROOTS = &GC_UNIQUE(GC_ROOTS)
+
+Object *gcMoveObject(Object *object);
+
+void gc(GC_PARAM);
+
+// MEMORY MANAGEMENT //////////////////////////////////////////////////////////
+
+size_t memoryAlign(size_t size, size_t alignment);
+
+Object *memoryAllocObject(Type type, size_t size, GC_PARAM);
+
+// CONSTRUCTING OBJECTS ///////////////////////////////////////////////////////
+
+Object *newObject(Type type, GC_PARAM);
+
+Object *newObjectFrom(Object **from, GC_PARAM);
+
+Object *newNumber(double number, GC_PARAM);
+
+Object *newObjectWithString(Type type, size_t size, GC_PARAM);
+
+Object *newStringWithLength(char *string, size_t length, GC_PARAM);
+
+Object *newString(char *string, GC_PARAM);
+
+Object *newCons(Object **car, Object **cdr, GC_PARAM);
+
+Object *newSymbolWithLength(char *string, size_t length, GC_PARAM);
+
+Object *newSymbol(char *string, GC_PARAM);
+
+Object *newObjectWithClosure(Type type, Object **closure, Object **params, Object **body, Object **env, GC_PARAM);
+
+Object *newLambda(Object **closure, Object **params, Object **body, Object **env, GC_PARAM);
+
+Object *newMacro(Object **closure, Object **params, Object **body, Object **env, GC_PARAM);
+
+Object *newPrimitive(int primitive, char *name, GC_PARAM);
+
+Object *newEnv(Object **func, Object **vals, GC_PARAM);
+
+// STREAM INPUT ///////////////////////////////////////////////////////////////
+
+/* The purpose of the stream functions is to provide an abstraction over file
+ * and string inputs. In order to accommodate the REPL, we need to be able to
+ * process character special files (such as stdin) character by character and
+ * evaluate expressions as they are being entered.
+ */
+
+int streamGetc(Stream *stream);
+
+Stream *streamSeek(Stream *stream, int offset);
+
+int streamPeek(Stream *stream);
+
+// READING S-EXPRESSIONS //////////////////////////////////////////////////////
+
+Object *readExpr(Stream *stream, GC_PARAM);
+
+int readNext(Stream *stream);
+
+int initialReadNext(Stream *stream);
+
+int peekForward(Stream *stream, bool shebang);
+
+int peekNext(Stream *stream);
+
+int readWhile(Stream *stream, int (*predicate)(int ch));
+
+Object *readUnary(Stream *stream, char *symbol, GC_PARAM);
+
+Object *readString(Stream *stream, GC_PARAM);
+
+int isSymbolChar(int ch);
+
+Object *readNumberOrSymbol(Stream *stream, GC_PARAM);
+
+Object *reverseList(Object *list);
+
+Object *readList(Stream *stream, GC_PARAM);
+
+
+// WRITING OBJECTS ////////////////////////////////////////////////////////////
+
+void writeObject(Object *object, bool readably, FILE *file);
+
+// ENVIRONMENT ////////////////////////////////////////////////////////////////
+
+/* An environment consists of a pointer to its parent environment (if any) and
+ * two parallel lists - vars and vals.
+ *
+ * Case 1 - vars is a regular list:
+ *   vars: (a b c), vals: (1 2 3)        ; a = 1, b = 2, c = 3
+ *
+ * Case 2 - vars is a dotted list:
+ *   vars: (a b . c), vals: (1 2)        ; a = 1, b = 2, c = nil
+ *   vars: (a b . c), vals: (1 2 3)      ; a = 1, b = 2, c = (3)
+ *   vars: (a b . c), vals: (1 2 3 4 5)  ; a = 1, b = 2, c = (3 4 5)
+ *
+ * Case 3 - vars is a symbol:
+ *   vars: a, vals: nil                  ; a = nil
+ *   vars: a, vals: (1)                  ; a = (1)
+ *   vars: a, vals: (1 2 3)              ; a = (1 2 3)
+ *
+ * Case 4 - vars and vals are both nil:
+ *   vars: nil, vals: nil
+ */
+
+Object *envLookup(Object *var, Object *env);
+
+Object *envAdd(Object **var, Object **val, Object **env, GC_PARAM);
+
+Object *envSet(Object **var, Object **val, Object **env, GC_PARAM);
+
+// PRIMITIVES /////////////////////////////////////////////////////////////////
+
+Object *primitiveSpace(Object **args, GC_PARAM);
+
+Object *primitiveAtom(Object **args, GC_PARAM);
+
+/* Object *primitiveEq(Object **args, GC_PARAM);
+ */
+
+Object *primitiveDif(Object **args, GC_PARAM);
+
+Object *primitiveCar(Object **args, GC_PARAM);
+
+Object *primitiveCdr(Object **args, GC_PARAM);
+
+Object *primitiveCons(Object **args, GC_PARAM);
+
+Object *primitivePrint(Object **args, GC_PARAM);
+
+Object *primitivePrinc(Object **args, GC_PARAM);
+
+Object *primitiveNewline(Object **args, GC_PARAM);
+
+Object *primitiveRead(Object **args, GC_PARAM);
+
+Object *name(Object **args, GC_PARAM);
+
+
+// EVALUATION /////////////////////////////////////////////////////////////////
+
+/* Scheme-style tail recursive evaluation. evalProg, evalProgs, evalCond, and
+ * PRIMITIVE_EVAL, return the object in the tail recursive position to be
+ * evaluated by evalExpr. Macros are expanded in-place the first time they are
+ * evaluated.
+ */
+
+Object *evalExpr(Object **object, Object **env, GC_PARAM);
+
+Object *evalSet(Object **args, Object **env, GC_PARAM);
+
+Object *evalProg(Object **args, Object **env, GC_PARAM);
+
+Object *progs1(Object **stop, Object **body, Object **env, GC_PARAM);
+
+Object *evalProgs(Object **args, Object **env, GC_PARAM);
+
+Object *evalCond(Object **args, Object **env, GC_PARAM);
+
+Object *evalFill(Object **args, Object **env, GC_PARAM);
+
+Object *evalLambda(Object **args, Object **env, GC_PARAM);
+
+Object *evalMacro(Object **args, Object **env, GC_PARAM);
+
+Object *expandMacro(Object **macro, Object **args, GC_PARAM);
+
+Object *expandMacroTo(Object **macro, Object **args, Object **cons, GC_PARAM);
+
+Object *evalList(Object **args, Object **env, GC_PARAM);
+
+Object *evalRead(GC_PARAM);
+
+Object *newRootEnv(GC_PARAM);
+
+#endif