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\ @(#) smart_if.fth 98/01/26 1.2
\ Smart Conditionals
\ Allow use of if, do, begin, etc.outside of colon definitions.
\
\ Thanks to Mitch Bradley for the idea.
\
\ Author: Phil Burk
\ Copyright 1994 3DO, Phil Burk, Larry Polansky, Devid Rosenboom
\
\ The pForth software code is dedicated to the public domain,
\ and any third party may reproduce, distribute and modify
\ the pForth software code or any derivative works thereof
\ without any compensation or license. The pForth software
\ code is provided on an "as is" basis without any warranty
\ of any kind, including, without limitation, the implied
\ warranties of merchantability and fitness for a particular
\ purpose and their equivalents under the laws of any jurisdiction.
anew task-smart_if.fth
variable SMIF-XT \ execution token for conditional code
variable SMIF-DEPTH \ depth of nested conditionals
: SMIF{ ( -- , if executing, start compiling, setup depth )
state @ 0=
IF
:noname smif-xt !
1 smif-depth !
ELSE
1 smif-depth +!
THEN
;
: }SMIF ( -- , unnest, stop compiling, execute code and forget )
smif-xt @
IF
-1 smif-depth +!
smif-depth @ 0 <=
IF
postpone ; \ stop compiling
smif-xt @ execute \ execute conditional code
smif-xt @ >code dp ! \ forget conditional code
0 smif-xt ! \ clear so we don't mess up later
THEN
THEN
;
\ redefine conditionals to use smart mode
: IF smif{ postpone if ; immediate
: DO smif{ postpone do ; immediate
: ?DO smif{ postpone ?do ; immediate
: BEGIN smif{ postpone begin ; immediate
: THEN postpone then }smif ; immediate
: REPEAT postpone repeat }smif ; immediate
: UNTIL postpone until }smif ; immediate
: LOOP postpone loop }smif ; immediate
: +LOOP postpone +loop }smif ; immediate
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