Forth
=====
This is a new implementation of Forth 2012 in C.
Building & use
--------------
Use cmake or `build.sh` . It probably needs GCC with `--std=gnu99` .
You get a binary with the forth runtime. Run it to get a prompt. Use `-h` for help.
Goals
-----
- Comfy to use and extend
- No dynamic allocation where possible
- Compact and embeddable so it can be ported to ARM-CortexM or similar later
- Implement the CORE and CORE-EXT word sets, for a start
- Pass the [Forth2012 test suite ](https://github.com/gerryjackson/forth2012-test-suite ), at least for the word sets that are implemented
- Maybe eventually have some terminal-based implementation of (a subset of) the Facility word set, like AT-XY and keyboard input
- Try to keep added custom words and quirks at a minimum
- Comment stuff, maybe
Non-Goals
---------
- I don't really care about implementing some of the word sets
- Performance is not so critical for a hobby Forth like this
- Probably won't accept merge requests, this is my Forth
- I also don't care about someone telling me to add a license file
Custom words
------------
- `.\"` - like `."` but allows escaping, this is essentially `S\" blah" TYPE` , but without allocation (unless compiled)
- `??` - debug dump of the stacks
- `reset` - everything should become like if you restarted the program
- `debug ( flag -- )` - enable or disable verbose logging
For debug, there is `see ( "word" -- )` that lets you inspect and disassemble dictionary entries.
Implementation status
---------------------
*(this section may be outdated)*
Implemented and tested:
```
CORE:
! ' ( * * / */MOD + +! +LOOP , - . ." # #> #S <# >BODY >NUMBER / /mod 0< 0= 1+ 1- 2! 2* 2/ 2@ 2DROP 2DUP 2OVER 2SWAP
: ; < = > >IN >R ?DUP @ ABORT ABORT" ABS ALIGN ALIGNED ALLOT AND BASE BEGIN BL C! C, C@ CELL CELL+ CELLS CHAR CHAR+
CHARS CONSTANT COUNT CR CREATE DECIMAL DEPTH DO DOES> DROP DUP ELSE EMIT ENVIRONMENT? EVALUATE EXECUTE EXIT FILL FM/MOD FIND
HERE HOLD I IF IMMEDIATE INVERT J LEAVE LITERAL LOOP LSHIFT M* MAX MIN MOD MOVE NEGATE OR OVER POSTPONE QUIT R> R@ RECURSE
REPEAT ROT RSHIFT S>D S" SIGN SM/REM SOURCE SPACE SPACES STATE SWAP THEN TYPE U. U< UNTIL UM * UM / MOD UNLOOP VARIABLE WHILE WORD XOR [ [ ' ] [ CHAR ] ]
CORE-EXT:
.( .R :NONAME 0< > 0> 2>R 2R> 2R@ < > ?DO ACTION-OF AGAIN BUFFER: C" CASE COMPILE, DEFER DEFER! DEFER@ ENDCASE ENDOF ERASE FALSE HEX HOLDS IS MARKER NIP OF PAD PARSE PARSE-NAME PICK RESTORE-INPUT SAVE-INPUT ROLL S\" TO TRUE TUCK U.R U> UNUSED VALUE WITHIN
\
Other sets:
FORGET SEE BYE INCLUDE INCLUDED
```
Missing:
```
CORE:
ACCEPT KEY
CORE-EXT:
REFILL SOURCE-ID [COMPILE]
```
.
