Annotation of gforth/kernel/cbr.fs, revision 1.6

1.1       jwilke      1: \ Structural Conditionals, based on branches               12dec92py
                      2: 
1.6     ! anton       3: \ Copyright (C) 1995,1996,1997,1999,2001,2003 Free Software Foundation, Inc.
1.1       jwilke      4: 
                      5: \ This file is part of Gforth.
                      6: 
                      7: \ Gforth is free software; you can redistribute it and/or
                      8: \ modify it under the terms of the GNU General Public License
                      9: \ as published by the Free Software Foundation; either version 2
                     10: \ of the License, or (at your option) any later version.
                     11: 
                     12: \ This program is distributed in the hope that it will be useful,
                     13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
                     14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     15: \ GNU General Public License for more details.
                     16: 
                     17: \ You should have received a copy of the GNU General Public License
                     18: \ along with this program; if not, write to the Free Software
1.3       anton      19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
1.1       jwilke     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: 
1.4       jwilke     32: : AHEAD     postpone branch >mark ;           immediate restrict
                     33: : IF        postpone ?branch >mark ;          immediate restrict
1.1       jwilke     34: : THEN      sys? dup @ ?struc >resolve ;     immediate restrict
1.4       jwilke     35: : ELSE      sys? postpone AHEAD swap postpone THEN ;
1.1       jwilke     36:                                              immediate restrict
                     37: 
                     38: ' THEN Alias ENDIF immediate restrict
                     39: 
                     40: : BEGIN     here ;                           immediate restrict
1.4       jwilke     41: : WHILE     sys? postpone IF swap ;           immediate restrict
                     42: : AGAIN     sys? postpone branch  <resolve ;  immediate restrict
                     43: : UNTIL     sys? postpone ?branch <resolve ;  immediate restrict
                     44: : REPEAT    over 0= ?struc postpone AGAIN postpone THEN ;
1.1       jwilke     45:                                              immediate restrict
                     46: 

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