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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 |