collapseos/apps/forth/core.fth

: H HERE @ ;
: -^ SWAP - ;
: +! SWAP OVER @ + SWAP ! ;
: ALLOT HERE +! ;
: , H ! 2 ALLOT ;
: C, H C! 1 ALLOT ;
: NOT 1 SWAP SKIP? EXIT 0 * ;
: RECURSE R> R> 2 - >R >R EXIT ;
: ( LIT@ ) WORD SCMP NOT SKIP? RECURSE ; IMMEDIATE
( Hello, hello, krkrkrkr... do you hear me? )
( Ah, voice at last! Some lines above need comments )
( BTW: Forth lines limited to 64 cols because of default )
( input buffer size in Collapse OS )
( NOT: a bit convulted because we don't have IF yet )
( RECURSE: RS TOS is for RECURSE itself, then we have to dig )
( one more level to get to RECURSE's parent's caller. )
( IF true, skip following (fbr). Also, push br cell ref H, )
( to PS )
: IF ['] SKIP? , ['] (fbr) , H 1 ALLOT ; IMMEDIATE
( Subtract TOS from H to get offset to write to IF or ELSE's )
( br cell )
: THEN DUP H -^ SWAP C! ; IMMEDIATE
( write (fbr) addr, allot, then same as THEN )
: ELSE ['] (fbr) , 1 ALLOT DUP H -^ SWAP C! H 1 - ; IMMEDIATE
: ? @ . ;
: VARIABLE CREATE 2 ALLOT ;
: CONSTANT CREATE H ! DOES> @ ;
: = CMP NOT ;
: < CMP 0 1 - = ;
: > CMP 1 = ;