Annotation of gforth/kernel/toolsext.fs, revision 1.19

1.18      anton       1: \ Copyright (C) 1995,1998,2000,2003 Free Software Foundation, Inc.
1.1       anton       2: 
                      3: \ This file is part of Gforth.
                      4: 
                      5: \ Gforth is free software; you can redistribute it and/or
                      6: \ modify it under the terms of the GNU General Public License
                      7: \ as published by the Free Software Foundation; either version 2
                      8: \ of the License, or (at your option) any later version.
                      9: 
                     10: \ This program is distributed in the hope that it will be useful,
                     11: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
                     12: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     13: \ GNU General Public License for more details.
                     14: 
                     15: \ You should have received a copy of the GNU General Public License
                     16: \ along with this program; if not, write to the Free Software
1.12      anton      17: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
1.1       anton      18: 
1.3       jwilke     19: Warnings off
1.1       anton      20: 
                     21: Variable countif
                     22: 
                     23: : dummy ;  immediate
                     24: : >exec  >r ; restrict ( :-)
1.10      anton      25: : scanIF   f83find  dup 0=  IF  drop ['] dummy >head-noprim  THEN  ;
1.1       anton      26: 
1.2       jwilke     27: Create [struct]-search    ' scanIF A,  ' (reveal) A,  ' drop A, ' drop A,
1.5       pazsan     28: Create [struct]-voc       [struct]-search A,
                     29:                           NIL A,       NIL A,       NIL A,
1.1       anton      30: 
                     31: : ?if  countif @ 0<
                     32:   IF  [ [struct]-voc 3 cells + ] ALiteral @ lookup !  THEN ;
                     33: 
                     34: UNLOCK  Tlast @ TNIL Tlast !  LOCK
                     35: \ last @  0 last !
                     36: 
1.8       crook      37: : [IF]
                     38:   1 countif +! ?if ;       immediate
                     39: : [THEN]
                     40:   -1 countif +! ?if ;       immediate
                     41: : [ELSE]
                     42:   postpone [THEN] postpone [IF] ;
1.1       anton      43:                                      immediate
                     44: ' [IF]   Alias [IFDEF]               immediate
                     45: ' [IF]   Alias [IFUNDEF]             immediate
1.8       crook      46: ' [THEN] Alias [ENDIF]               immediate
1.1       anton      47: ' [IF]   Alias [BEGIN]               immediate
                     48: ' [IF]   Alias [WHILE]               immediate
                     49: ' [THEN] Alias [UNTIL]               immediate
                     50: ' [THEN] Alias [AGAIN]               immediate
                     51: ' [IF]   Alias [DO]                  immediate
                     52: ' [IF]   Alias [?DO]                 immediate
                     53: ' [THEN] Alias [LOOP]                immediate
                     54: ' [THEN] Alias [+LOOP]               immediate
                     55: : [REPEAT]  postpone [AGAIN] postpone [THEN] ;
                     56:                                      immediate
1.17      anton      57: \ The following was too smart for its own good; consider "postpone (".
                     58: \ Moreover, ANS Forth specifies that the next [THEN] ends an [IF]
                     59: \ (even if its in a '( ... )').
                     60: 
                     61: \ ' ( Alias (                          immediate ( keep fontify happy)
                     62: \ ' \ Alias \                          immediate
1.1       anton      63: 
                     64: UNLOCK Tlast @ swap Tlast ! LOCK
                     65: \ last @ swap last !
1.5       pazsan     66: 1 cells - [struct]-voc cell+ !
1.1       anton      67: 
                     68: \ Interpretative Structuren                            30apr92py
                     69: 
1.13      pazsan     70: : [defined] ( "<spaces>name" -- flag )   bl word find nip 0<> ; immediate
                     71:   \G returns true if name is found in current search order
1.14      anton      72: ' [defined] alias defined immediate
1.13      pazsan     73: : [undefined] ( "<spaces>name" -- flag ) postpone [defined] 0= ; immediate
                     74:   \G returns false if name is found in current search order
1.8       crook      75: 
1.13      pazsan     76: : [IF] ( flag -- ) \ tools-ext bracket-if
1.8       crook      77:   \G If flag is @code{TRUE} do nothing (and therefore
                     78:   \G execute subsequent words as normal). If flag is @code{FALSE},
                     79:   \G parse and discard words from the parse
                     80:   \G area (refilling it if necessary using
                     81:   \G @code{REFILL}) including nested instances of @code{[IF]}..
                     82:   \G @code{[ELSE]}.. @code{[THEN]} and @code{[IF]}.. @code{[THEN]}
                     83:   \G until the balancing @code{[ELSE]} or @code{[THEN]} has been
                     84:   \G parsed and discarded. Immediate word.
                     85:        0= IF  countif off
1.1       anton      86:               lookup @ [ [struct]-voc 3 cells + ] ALiteral !
                     87:              [struct]-voc lookup !
                     88:           THEN ;                                      immediate
1.8       crook      89: 
                     90: : [IFDEF] ( "<spaces>name" -- ) \ gforth bracket-if-def
                     91:   \G If name is found in the current search-order, behave like
1.9       crook      92:   \G @code{[IF]} with a @code{TRUE} flag, otherwise behave like
1.8       crook      93:   \G @code{[IF]} with a @code{FALSE} flag. Immediate word.
1.13      pazsan     94:   postpone [defined]    postpone [IF] ;                 immediate
1.8       crook      95: 
                     96: : [IFUNDEF] ( "<spaces>name" -- ) \ gforth bracket-if-un-def
                     97:   \G If name is not found in the current search-order, behave like
1.9       crook      98:   \G @code{[IF]} with a @code{TRUE} flag, otherwise behave like
1.8       crook      99:   \G @code{[IF]} with a @code{FALSE} flag. Immediate word.
1.13      pazsan    100:   postpone [defined] 0= postpone [IF] ;                 immediate
1.8       crook     101: 
1.13      pazsan    102: : [ELSE]  ( -- ) \ tools-ext bracket-else
1.8       crook     103:   \G Parse and discard words from the parse
                    104:   \G area (refilling it if necessary using
                    105:   \G @code{REFILL}) including nested instances of @code{[IF]}..
                    106:   \G @code{[ELSE]}.. @code{[THEN]} and @code{[IF]}.. @code{[THEN]}
                    107:   \G until the balancing @code{[THEN]} has been parsed and discarded.
                    108:   \G @code{[ELSE]} only gets executed if the balancing @code{[IF]}
                    109:   \G was @code{TRUE}; if it was @code{FALSE}, @code{[IF]} would
                    110:   \G have parsed and discarded the @code{[ELSE]}, leaving the
                    111:   \G subsequent words to be executed as normal.
                    112:   \G Immediate word.
                    113:   0 postpone [IF] ;                                   immediate
                    114: 
                    115: : [THEN] ( -- ) \ tools-ext bracket-then
                    116:   \G Do nothing; used as a marker for other words to parse
1.9       crook     117:   \G and discard up to. Immediate word.
1.8       crook     118:   ;                                                   immediate
                    119: 
                    120: : [ENDIF] ( -- ) \ gforth bracket-end-if
1.9       crook     121:   \G Do nothing; synonym for @code{[THEN]}
1.8       crook     122:   ;                                                   immediate
1.1       anton     123: 
                    124: \ Structs for interpreter                              28nov92py
                    125: 
                    126: User (i)
                    127: 
1.8       crook     128: : [DO]  ( n-limit n-index -- ) \ gforth bracket-do
                    129:   >in @ -rot
1.1       anton     130:   DO   I (i) ! dup >r >in ! interpret r> swap +LOOP  drop ;
                    131:                                                       immediate
1.8       crook     132: 
                    133: : [?DO] ( n-limit n-index -- ) \ gforth bracket-question-do
                    134:   2dup = IF 2drop postpone [ELSE] ELSE postpone [DO] THEN ;
1.1       anton     135:                                                       immediate
1.8       crook     136: 
                    137: : [+LOOP] ( n -- ) \ gforth bracket-question-plus-loop
1.19    ! pazsan    138:   rdrop ;                                             immediate
1.8       crook     139: 
                    140: : [LOOP] ( -- ) \ gforth bracket-loop
1.19    ! pazsan    141:   1 rdrop ;                                           immediate
1.8       crook     142: 
                    143: : [FOR] ( n -- ) \ gforth bracket-for
                    144:   0 swap postpone [DO] ;                              immediate
                    145: 
                    146: : [NEXT] ( n -- ) \ gforth bracket-next
1.19    ! pazsan    147:   -1 rdrop ;                                          immediate
1.8       crook     148: 
1.4       pazsan    149: :noname (i) @ ;
                    150: :noname (i) @ postpone Literal ;
1.8       crook     151: interpret/compile: [I] ( -- n ) \ gforth bracket-i
                    152: 
                    153: : [BEGIN] ( -- ) \ gforth bracket-begin
                    154:   >in @ >r BEGIN r@ >in ! interpret UNTIL rdrop ;     immediate
                    155: 
                    156: ' [+LOOP]  Alias [UNTIL] ( flag -- ) \ gforth bracket-until
1.1       anton     157:                                                       immediate
1.8       crook     158: 
                    159: : [REPEAT]  ( -- ) \ gforth bracket-repeat
1.19    ! pazsan    160:   false rdrop ;                                       immediate
1.8       crook     161: 
                    162: ' [REPEAT] Alias [AGAIN] ( -- ) \ gforth bracket-again
                    163:                                                       immediate
                    164: 
                    165: : [WHILE]   ( flag -- ) \ gforth bracket-while
1.19    ! pazsan    166:   0= IF   postpone [ELSE] true rdrop 1 countif +!  THEN ;
1.1       anton     167:                                                       immediate
                    168: 
1.3       jwilke    169: Warnings on

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