collapseos/forth/parse.fs

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( requires core, str )
( string being sent to parse routines are always null
terminated )
: (parsec) ( a -- n f )
( apostrophe is ASCII 39 )
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DUP C@ 39 = NOT IF 0 EXIT THEN ( a 0 )
DUP 2+ C@ 39 = NOT IF 0 EXIT THEN ( a 0 )
( surrounded by apos, good, return )
1+ C@ 1 ( n 1 )
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;
( returns negative value on error )
: _ ( c -- n )
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( '0' is ASCII 48 )
48 -
DUP 0< IF EXIT THEN ( bad )
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DUP 10 < IF EXIT THEN ( good )
( 'a' is ASCII 97. 59 = 97 - 48 )
49 -
DUP 0< IF EXIT THEN ( bad )
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DUP 6 < IF 10 + EXIT THEN ( good )
( bad )
255 -
;
: (parseh) ( a -- n f )
( '0': ASCII 0x30 'x': 0x78 0x7830: 30768 )
DUP @ 30768 = NOT IF 0 EXIT THEN ( a 0 )
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( We have "0x" prefix )
2+
0 ( a r )
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BEGIN
SWAP C@+ ( r a+1 c )
DUP NOT IF 2DROP 1 EXIT THEN ( r, 1 )
_ ( r a n )
DUP 0< IF ROT 2DROP 0 EXIT THEN ( a 0 )
ROT 16 * + ( a r*16+n )
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AGAIN
;
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( returns negative value on error )
: _ ( c -- n )
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( '0' is ASCII 48 )
48 -
DUP 0< IF EXIT THEN ( bad )
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DUP 2 < IF EXIT THEN ( good )
( bad )
255 -
;
: (parseb) ( a -- n f )
( '0': ASCII 0x30 'b': 0x62 0x6230: 25136 )
DUP @ 25136 = NOT IF 0 EXIT THEN ( a 0 )
( We have "0b" prefix )
2+
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0 ( a r )
BEGIN
SWAP C@+ ( r a+1 c )
DUP NOT IF 2DROP 1 EXIT THEN ( r 1 )
_ ( r a n )
DUP 0< IF ROT 2DROP 0 EXIT THEN ( a 0 )
ROT 2 * + ( a r*2+n )
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AGAIN
;
: (parse) ( a -- n )
(parsec) IF EXIT THEN
(parseh) IF EXIT THEN
(parseb) IF EXIT THEN
(parsed) IF EXIT THEN
( nothing works )
LIT< (wnf) (find) IF EXECUTE ELSE ABORT THEN
;
' (parse) (parse*) !