| bb6b2dcd |
1 | \ @(#) smart_if.fth 98/01/26 1.2\r |
| 2 | \ Smart Conditionals\r |
| 3 | \ Allow use of if, do, begin, etc.outside of colon definitions.\r |
| 4 | \\r |
| 5 | \ Thanks to Mitch Bradley for the idea.\r |
| 6 | \\r |
| 7 | \ Author: Phil Burk\r |
| 8 | \ Copyright 1994 3DO, Phil Burk, Larry Polansky, Devid Rosenboom\r |
| 9 | \\r |
| 10 | \ The pForth software code is dedicated to the public domain,\r |
| 11 | \ and any third party may reproduce, distribute and modify\r |
| 12 | \ the pForth software code or any derivative works thereof\r |
| 13 | \ without any compensation or license. The pForth software\r |
| 14 | \ code is provided on an "as is" basis without any warranty\r |
| 15 | \ of any kind, including, without limitation, the implied\r |
| 16 | \ warranties of merchantability and fitness for a particular\r |
| 17 | \ purpose and their equivalents under the laws of any jurisdiction.\r |
| 18 | \r |
| 19 | anew task-smart_if.fth\r |
| 20 | \r |
| 21 | variable SMIF-XT \ execution token for conditional code\r |
| 22 | variable SMIF-DEPTH \ depth of nested conditionals\r |
| 23 | \r |
| 24 | : SMIF{ ( -- , if executing, start compiling, setup depth )\r |
| 25 | state @ 0=\r |
| 26 | IF\r |
| 27 | :noname smif-xt !\r |
| 28 | 1 smif-depth !\r |
| 29 | ELSE\r |
| 30 | 1 smif-depth +!\r |
| 31 | THEN\r |
| 32 | ;\r |
| 33 | \r |
| 34 | : }SMIF ( -- , unnest, stop compiling, execute code and forget )\r |
| 35 | smif-xt @\r |
| 36 | IF\r |
| 37 | -1 smif-depth +!\r |
| 38 | smif-depth @ 0 <=\r |
| 39 | IF\r |
| 40 | postpone ; \ stop compiling\r |
| 41 | smif-xt @ execute \ execute conditional code\r |
| 42 | smif-xt @ >code dp ! \ forget conditional code\r |
| 43 | 0 smif-xt ! \ clear so we don't mess up later\r |
| 44 | THEN\r |
| 45 | THEN\r |
| 46 | ;\r |
| 47 | \r |
| 48 | \ redefine conditionals to use smart mode\r |
| 49 | : IF smif{ postpone if ; immediate\r |
| 50 | : DO smif{ postpone do ; immediate\r |
| 51 | : ?DO smif{ postpone ?do ; immediate\r |
| 52 | : BEGIN smif{ postpone begin ; immediate\r |
| 53 | : THEN postpone then }smif ; immediate\r |
| 54 | : REPEAT postpone repeat }smif ; immediate\r |
| 55 | : UNTIL postpone until }smif ; immediate\r |
| 56 | : LOOP postpone loop }smif ; immediate\r |
| 57 | : +LOOP postpone +loop }smif ; immediate\r |
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