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| 1 : | anton | 1.1 | \ Structural Conditionals 12dec92py |
| 2 : | |||
| 3 : | anton | 1.2 | \ Copyright (C) 1995,1996,1997 Free Software Foundation, Inc. |
| 4 : | anton | 1.1 | |
| 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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