[gforth] / gforth / kernel / cbr.fs  

gforth: gforth/kernel/cbr.fs


1 : jwilke 1.1 \ Structural Conditionals, based on branches 12dec92py
2 :    
3 :     \ Copyright (C) 1995,1996,1997 Free Software Foundation, Inc.
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5 :     \ This file is part of Gforth.
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8 :     \ modify it under the terms of the GNU General Public License
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15 :     \ GNU General Public License for more details.
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20 :    
21 :     : ?struc ( flag -- ) abort" unstructured " ;
22 :     : sys? ( sys -- ) dup 0= ?struc ;
23 :     : >mark ( -- sys ) here 0 , ;
24 :     : >resolve ( sys -- ) here over - swap ! ;
25 :     : <resolve ( sys -- ) here - , ;
26 :    
27 :     : BUT sys? swap ; immediate restrict
28 :     : YET sys? dup ; immediate restrict
29 :    
30 :     \ Structural Conditionals 12dec92py
31 :    
32 :     : AHEAD compile branch >mark ; immediate restrict
33 :     : IF compile ?branch >mark ; immediate restrict
34 :     : THEN sys? dup @ ?struc >resolve ; immediate restrict
35 :     : ELSE sys? compile AHEAD swap compile THEN ;
36 :     immediate restrict
37 :    
38 :     ' THEN Alias ENDIF immediate restrict
39 :    
40 :     : BEGIN here ; immediate restrict
41 :     : WHILE sys? compile IF swap ; immediate restrict
42 :     : AGAIN sys? compile branch <resolve ; immediate restrict
43 :     : UNTIL sys? compile ?branch <resolve ; immediate restrict
44 :     : REPEAT over 0= ?struc compile AGAIN compile THEN ;
45 :     immediate restrict
46 :    

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