Forth Cookbook

Cookbook (cook·book) a book containing recipes and other information about the preparation and cooking of food.

The way I cook in the Forth programming language. Let me cook!.

This cookbook is using pforth forth implementation.

All Forth Word Capitalize

Souce ¹

Tools Preparation

git clone https://github.com/philburk/pforth.git
cd pforth
cmake -S . -B build -G Ninja
cmake --build build

Let’s Cook

./fth/pforth_standalone

Hello World

CR is EMIT newline

." It's Forth" CR

Stack Manipulation Cheat Sheet

.     ( N --                   , print number on top of stack )
DUP   ( n -- n n               , DUPlicate top of stack )
SWAP  ( a b -- b a             , swap top two items on stack )
OVER  ( a b -- a b a           , copy second item on stack )
DROP  ( a --                   , remove item from the stack )
ROT   ( a b c -- b c a         , ROTate third item to top )
NIP   ( a b -- b               , remove second item from stack )
TUCK  ( a b -- b a b           , copy top item to third position )
?DUP  ( n -- n n | 0           , duplicate only if non-zero, '|' means OR )
-ROT  ( a b c -- c a b         , rotate top to third position )
2SWAP ( a b c d -- c d a b     , swap pairs )
2OVER ( a b c d -- a b c d a b , leapfrog pair )
2DUP  ( a b -- a b a b         , duplicate pair )
2DROP ( a b --                 , remove pair )
PICK  ( ... v3 v2 v1 v0 N -- ... v3 v2 v1 v0 vN )

New World

: SQUARE ( N -- N*N , calculate square )
    DUP *
;

Logic

In forth FALSE is 0 and TRUE is -1 or any number that not zero is TRUE

Conditional

ELSE is Optional

: GT4? ( -- , check if greater than 4 )
    DUP 4 >
    IF ." YES"
    ELSE ." NO"
    THEN
;

: PRINT.NUM ( -- , print a number )
    CASE
        0 OF ." ZERO" ENDOF
        1 OF ." ONE" ENDOF
        2 OF ." TWO" ENDOF
        3 OF ." THREE" ENDOF
        4 OF ." FORTH" ENDOF
        DUP . ." WHO?"
    ENDCACE
;

LOOP

: COUNT.UP ( N -- , print number 0 to N )
    0
    BEGIN
        DUP .
        1 +
        2DUP <
    UNTIL
    2DROP
;

I is Special (Optional)

: COUNT.UP ( N -- , print number 0 to N )
    1 + 0
    DO
        I .
    LOOP
;

in DO … LOOP you can also LEAVE

: COUNT.UP ( N -- , print number 0 no N )
    1 + 0
    BEGIN
        2DUP >
    WHILE
        DUP .
        1 +
    REPEAT
    2DROP
;

Input Output

CHAR   ( address -- address'       , add the size of one character )
COUNT  ( $addr -- addr #bytes      , extract string information ) 
TYPE   ( addr #bytes --            , output characters at addr )
ACCEPT ( addr maxbytes -- numbytes , input text, save at address )  

S and C is add string to stack, but C add null termination

: GREET ( -- , print friendly )
    S" Hello Friend" TYPE
;

: GREET ( -- , print friendly )
    C" Hello Friend" COUNT TYPE
;

Numeric Base

HEX, DECIMAL & BINARY for changing base

6 BINARY
6 DECIMAL
6 HEX

also can change any BASE, BASE is variable

7 BASE !

Sauce