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March 2014 update

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Ingy döt Net 2014-04-02 16:56:35 +00:00
parent 09687c4926
commit a25938f123
1846 changed files with 21876 additions and 5203 deletions
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36
Task/Short-circuit-evaluation/Forth/short-circuit-evaluation.fth
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@ -1,20 +1,28 @@
\ short-circuit conditional syntax, from Wil Baden
: COND 0 ; immediate
: THENS BEGIN dup WHILE postpone THEN REPEAT DROP ; immediate
: ORIF s" ?DUP 0= IF" evaluate ; immediate
: ANDIF s" DUP IF DROP" evaluate ; immediate
\ Short-circuit evaluation definitions from Wil Baden, with minor name changes
: ENDIF postpone THEN ; immediate
: .bool IF ." true " ELSE ." false" THEN ;
: A ." A=" dup .bool ;
: B ." B=" dup .bool ;
: COND 0 ; immediate
: ENDIFS BEGIN DUP WHILE postpone ENDIF REPEAT DROP ; immediate
: ORELSE s" ?DUP 0= IF" evaluate ; immediate
: ANDIF s" DUP IF DROP" evaluate ; immediate
: .bool IF ." true " ELSE ." false " THEN ;
: A ." A=" DUP .bool ;
: B ." B=" DUP .bool ;
: test
CR
1 -1 DO 1 -1 DO
CR I A drop space J B drop space
." : ANDIF " COND I A ANDIF drop J B IF ." (BOTH)" THENS
." , ORIF " COND I A ORIF drop J B 0= IF ." (NEITHER)" THENS
COND I A ANDIF J B ENDIFS ." ANDIF=" .bool CR
COND I A ORELSE J B ENDIFS ." ORELSE=" .bool CR
LOOP LOOP ;
\ a more typical example
: alnum? ( char -- ? )
COND dup lower? ORIF dup upper? ORIF dup digit? THENS nip ;
\ An alternative based on explicitly short-circuiting conditionals, Dave Keenan
: END-PRIOR-IF 1 CS-ROLL postpone ENDIF ; immediate
: test
CR
1 -1 DO 1 -1 DO
I A IF J B IF 1 ELSE END-PRIOR-IF 0 ENDIF ." ANDIF=" .bool CR
I A 0= IF J B IF END-PRIOR-IF 1 ELSE 0 ENDIF ." ORELSE=" .bool CR
LOOP LOOP ;