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| -rw-r--r-- | .gitignore | 4 | ||||
| -rw-r--r-- | COPYING | 674 | ||||
| -rw-r--r-- | LICENSES/GFDL-1.3-or-later.txt | 451 | ||||
| -rw-r--r-- | LICENSES/GPL-3.0-or-later.txt | 674 | ||||
| -rw-r--r-- | LICENSES/Unlicense.txt | 24 | ||||
| -rw-r--r-- | Makefile | 94 | ||||
| -rw-r--r-- | README.md | 377 | ||||
| -rw-r--r-- | TAGS | 106 | ||||
| -rw-r--r-- | THANKS | 5 | ||||
| -rw-r--r-- | TODO | 38 | ||||
| -rw-r--r-- | examples/hanoi.lali | 21 | ||||
| -rw-r--r-- | examples/mandelbrot.lali | 30 | ||||
| -rw-r--r-- | lali.c | 160 | ||||
| -rw-r--r-- | liblali.c | 1404 | ||||
| -rw-r--r-- | liblali.h | 362 | ||||
| -rw-r--r-- | test/main.lali | 40 | ||||
| -rwxr-xr-x | test/other/executables/emacs.el | 3 | ||||
| -rwxr-xr-x | test/other/executables/empty.lisp | 0 | ||||
| -rwxr-xr-x | test/other/executables/script.lali | 4 | ||||
| -rw-r--r-- | test/other/lexical.lali | 15 | ||||
| -rw-r--r-- | test/other/mundo.lali | 4 | ||||
| -rw-r--r-- | test/other/ola.lali | 3 | ||||
| -rw-r--r-- | test/other/universal.lali | 1 | ||||
| -rw-r--r-- | work-in-progress/Makefile | 94 | ||||
| -rw-r--r-- | work-in-progress/TAGS | 104 | ||||
| -rw-r--r-- | work-in-progress/lali.c | 173 | ||||
| -rw-r--r-- | work-in-progress/liblali.c | 1339 | ||||
| -rw-r--r-- | work-in-progress/liblali.h | 337 |
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diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..7c502a1 --- /dev/null +++ b/.gitignore @@ -0,0 +1,4 @@ +lali +liblali.a +*.o +README.html @@ -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. 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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. 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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. 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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. 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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. 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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! @@ -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 memory39,1338 +Object *symbols symbols41,1389 +Object *nil nil42,1413 +Object *n n43,1469 +Object *t t44,1522 +Object *f f45,1575 +static unsigned int seed 47,1629 +jmp_buf exceptionEnv;49,1660 +void exceptionWithObject(54,1765 +Object *gcMoveObject(gcMoveObject114,4107 +void gc(136,4806 +size_t memoryAlign(183,6199 +Object *memoryAllocObject(memoryAllocObject187,6306 +Object *newObject(newObject216,7294 +Object *newObjectFrom(newObjectFrom220,7399 +Object *newNumber(newNumber226,7586 +Object *newObjectWithString(newObjectWithString232,7731 +Object *newStringWithLength(newStringWithLength239,7974 +Object *newString(newString267,8904 +Object *newCons(newCons271,9015 +Object *newSymbolWithLength(newSymbolWithLength278,9186 +Object *newSymbol(newSymbol293,9696 +Object *newObjectWithClosure(newObjectWithClosure297,9807 +Object *newLambda(newLambda318,10483 +Object *newMacro(newMacro322,10635 +Object *newPrimitive(newPrimitive326,10785 +Object *newEnv(newEnv333,10977 +int streamGetc(372,12345 +Stream *streamSeek(streamSeek440,14380 +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(readUnary499,15640 +Object *readString(readString512,16017 +int isSymbolChar(528,16547 +Object *readNumberOrSymbol(readNumberOrSymbol533,16672 +Object *reverseList(reverseList565,17640 +Object *readList(readList578,17840 +Object *readExpr(readExpr610,18830 +void writeObject(633,19549 +#define CASE(635,19637 +#undef CASE642,19948 +#define CASE(678,20949 +#undef CASE687,21348 +Object *envLookup(envLookup713,22169 +Object *envAdd(envAdd728,22526 +Object *envSet(envSet738,22829 +Object *primitiveSpace(primitiveSpace760,23413 +Object *primitiveAtom(primitiveAtom764,23506 +Object *primitiveDif(primitiveDif782,24090 +Object *primitiveCar(primitiveCar793,24495 +Object *primitiveCdr(primitiveCdr804,24731 +Object *primitiveCons(primitiveCons815,24967 +Object *primitivePrint(primitivePrint822,25143 +Object *primitivePrinc(primitivePrinc828,25284 +Object *primitiveNewline(primitiveNewline834,25426 +Object *primitiveRead(primitiveRead839,25516 +Object *primitiveTime(primitiveTime850,25762 +Object *primitiveRandom(primitiveRandom877,26414 +#define DEFINE_PRIMITIVE_ARITHMETIC(890,26794 +DEFINE_PRIMITIVE_ARITHMETIC(920,28871 +#define DEFINE_PRIMITIVE_RELATIONAL(926,29182 +typedef struct Primitive 954,30979 + char *name;name955,31006 + int nMinArgs,956,31020 + int nMinArgs, nMaxArgs;956,31020 + Object *(* eval)957,31046 +} Primitive;958,31091 +Primitive primitives[primitives960,31105 + 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(evalSet1021,33432 +Object *evalProg(evalProg1047,34162 +Object *progs1(progs11067,34584 +Object *evalProgs(evalProgs1093,35277 +Object *evalCond(evalCond1119,36027 +Object *evalFill(evalFill1142,36609 +Object *evalLambda(evalLambda1165,37191 +Object *evalMacro(evalMacro1172,37378 +Object *expandMacro(expandMacro1179,37563 +Object *expandMacroTo(expandMacroTo1189,37845 +Object *evalList(evalList1203,38235 +Object *evalExpr(evalExpr1217,38607 +#define LISP(1293,41772 +static char *stdlib stdlib1295,41804 +Object *newRootEnv(newRootEnv1351,43430 @@ -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 @@ -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) @@ -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 memory52,1580 +Object *symbols symbols54,1631 +Object *nil nil55,1655 +Object *n n56,1711 +Object *t t57,1764 +Object *f f58,1817 +jmp_buf exceptionEnv;60,1871 +void exceptionWithObject(64,1975 +Object *gcMoveObject(gcMoveObject124,4317 +void gc(146,5016 +size_t memoryAlign(194,6464 +Object *memoryAllocObject(memoryAllocObject198,6571 +Object *newObject(newObject227,7559 +Object *newObjectFrom(newObjectFrom231,7664 +Object *newNumber(newNumber237,7851 +Object *newObjectWithString(newObjectWithString243,7996 +Object *newStringWithLength(newStringWithLength250,8239 +Object *newString(newString278,9169 +Object *newCons(newCons282,9280 +Object *newSymbolWithLength(newSymbolWithLength289,9451 +Object *newSymbol(newSymbol304,9961 +Object *newObjectWithClosure(newObjectWithClosure308,10072 +Object *newLambda(newLambda330,10796 +Object *newMacro(newMacro334,10975 +Object *newPrimitive(newPrimitive338,11152 +Object *newEnv(newEnv345,11344 +int streamGetc(384,12712 +Stream *streamSeek(streamSeek452,14747 +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(readUnary511,16007 +Object *readString(readString524,16384 +int isSymbolChar(540,16914 +Object *readNumberOrSymbol(readNumberOrSymbol545,17039 +Object *reverseList(reverseList577,18007 +Object *readList(readList590,18207 +Object *readExpr(readExpr622,19197 +void writeObject(645,19916 +#define CASE(647,20004 +#undef CASE654,20315 +#define CASE(692,21367 +#undef CASE699,21670 +Object *envLookup(envLookup725,22491 +Object *envAdd(envAdd740,22848 +Object *envSet(envSet750,23151 +Object *primitiveSpace(primitiveSpace772,23735 +Object *primitiveAtom(primitiveAtom776,23828 +Object *primitiveDif(primitiveDif794,24412 +Object *primitiveCar(primitiveCar805,24817 +Object *primitiveCdr(primitiveCdr817,25126 +Object *primitiveCons(primitiveCons828,25362 +Object *primitivePrint(primitivePrint835,25538 +Object *primitivePrinc(primitivePrinc841,25679 +Object *primitiveNewline(primitiveNewline847,25821 +Object *primitiveRead(primitiveRead852,25911 +#define DEFINE_PRIMITIVE_ARITHMETIC(865,26159 +DEFINE_PRIMITIVE_ARITHMETIC(894,27946 +#define DEFINE_PRIMITIVE_RELATIONAL(899,28159 +typedef struct Primitive 925,29771 + char *name;name926,29798 + int nMinArgs,927,29812 + int nMinArgs, nMaxArgs;927,29812 + Object *(* eval)928,29838 +} Primitive;929,29883 +Primitive primitives[primitives931,29897 + 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(evalSet991,32147 +Object *evalProg(evalProg1017,32877 +Object *progs1(progs11031,33198 +Object *evalProgs(evalProgs1048,33601 +Object *evalCond(evalCond1072,34218 +Object *evalFill(evalFill1095,34800 +Object *evalLambda(evalLambda1118,35382 +Object *evalMacro(evalMacro1126,35627 +Object *expandMacro(expandMacro1134,35870 +Object *expandMacroTo(expandMacroTo1144,36152 +Object *evalList(evalList1158,36542 +Object *evalExpr(evalExpr1172,36914 +#define LISP(1249,40130 +static char *stdlib stdlib1251,40162 +Object *newRootEnv(newRootEnv1307,41788 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 |