Annotation of gforth/kernel/cond-old.fs, revision 1.1
1.1 ! anton 1: \ Structural Conditionals 12dec92py
! 2:
! 3: \ Copyright (C) 1995-1997 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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