File:  [gforth] / gforth / kernel / cond-old.fs
Revision 1.2: download - view: text, annotated - select for diffs
Tue Dec 8 22:03:08 1998 UTC (23 years, 10 months ago) by anton
Branches: MAIN
CVS tags: v0-4-0, HEAD
updated dates in copyright messages
inserted copyright messages in most files that did not have them
removed outdated files engine/32bit.h engine/strsig.c

    1: \ Structural Conditionals                              12dec92py
    2: 
    3: \ Copyright (C) 1995,1996,1997 Free Software Foundation, Inc.
    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
   19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: 
   21: 0 constant defstart
   22: 
   23: : ?struc      ( flag -- )       abort" unstructured " ;
   24: : sys?        ( sys -- )        dup 0= ?struc ;
   25: : >mark       ( -- sys )        here  0 , ;
   26: : >resolve    ( sys -- )        here over - swap ! ;
   27: : <resolve    ( sys -- )        here - , ;
   28: 
   29: : BUT       sys? swap ;                      immediate restrict
   30: : YET       sys? dup ;                       immediate restrict
   31: 
   32: \ Structural Conditionals                              12dec92py
   33: 
   34: : AHEAD     compile branch >mark ;           immediate restrict
   35: : IF        compile ?branch >mark ;          immediate restrict
   36: : THEN      sys? dup @ ?struc >resolve ;     immediate restrict
   37: : ELSE      sys? compile AHEAD swap compile THEN ;
   38:                                              immediate restrict
   39: 
   40: ' THEN Alias ENDIF immediate restrict
   41: 
   42: : BEGIN     here ;                           immediate restrict
   43: : WHILE     sys? compile IF swap ;           immediate restrict
   44: : AGAIN     sys? compile branch  <resolve ;  immediate restrict
   45: : UNTIL     sys? compile ?branch <resolve ;  immediate restrict
   46: : REPEAT    over 0= ?struc compile AGAIN compile THEN ;
   47:                                              immediate restrict
   48: 
   49: \ Structural Conditionals                              12dec92py
   50: 
   51: Variable leavings
   52: 
   53: : (leave)   here  leavings @ ,  leavings ! ;
   54: : LEAVE     compile branch  (leave) ;  immediate restrict
   55: : ?LEAVE    compile 0= compile ?branch  (leave) ;
   56:                                              immediate restrict
   57: 
   58: : DONE   ( addr -- )  leavings @
   59:   BEGIN  2dup u<=  WHILE  dup @ swap >resolve  REPEAT
   60:   leavings ! drop ;                          immediate restrict
   61: 
   62: \ Structural Conditionals                              12dec92py
   63: 
   64: : DO        compile (do)   here ;            immediate restrict
   65: 
   66: : ?DO       compile (?do)  (leave) here ;
   67:                                              immediate restrict
   68: : FOR       compile (for)  here ;            immediate restrict
   69: 
   70: : loop]     dup <resolve 2 cells - compile done compile unloop ;
   71: 
   72: : LOOP      sys? compile (loop)  loop] ;     immediate restrict
   73: : +LOOP     sys? compile (+loop) loop] ;     immediate restrict
   74: : NEXT      sys? compile (next)  loop] ;     immediate restrict
   75: 
   76: : EXIT compile ;s ; immediate restrict
   77: : ?EXIT postpone IF postpone EXIT postpone THEN ; immediate restrict
   78: 

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