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|
\ Copyright (C) 1995,1998,2000,2003,2005,2007 Free Software Foundation, Inc.
\ This file is part of Gforth.
\ Gforth is free software; you can redistribute it and/or
\ modify it under the terms of the GNU General Public License
\ as published by the Free Software Foundation, either version 3
\ of the License, or (at your option) any later version.
\ This program is distributed in the hope that it will be useful,
\ but WITHOUT ANY WARRANTY; without even the implied warranty of
\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
\ GNU General Public License for more details.
\ You should have received a copy of the GNU General Public License
\ along with this program. If not, see http://www.gnu.org/licenses/.
Warnings off
Variable countif
: dummy ; immediate
: >exec >r ; restrict ( :-)
: scanIF f83find dup 0= IF drop ['] dummy >head-noprim THEN ;
Create [struct]-search ' scanIF A, ' (reveal) A, ' drop A, ' drop A,
Create [struct]-voc [struct]-search A,
NIL A, NIL A, NIL A,
: ?if countif @ 0<
IF [ [struct]-voc 3 cells + ] ALiteral @ lookup ! THEN ;
UNLOCK Tlast @ TNIL Tlast ! LOCK
\ last @ 0 last !
: [IF]
1 countif +! ?if ; immediate
: [THEN]
-1 countif +! ?if ; immediate
: [ELSE]
postpone [THEN] postpone [IF] ;
immediate
' [IF] Alias [IFDEF] immediate
' [IF] Alias [IFUNDEF] immediate
' [THEN] Alias [ENDIF] immediate
' [IF] Alias [BEGIN] immediate
' [IF] Alias [WHILE] immediate
' [THEN] Alias [UNTIL] immediate
' [THEN] Alias [AGAIN] immediate
' [IF] Alias [DO] immediate
' [IF] Alias [?DO] immediate
' [THEN] Alias [LOOP] immediate
' [THEN] Alias [+LOOP] immediate
: [REPEAT] postpone [AGAIN] postpone [THEN] ;
immediate
\ The following was too smart for its own good; consider "postpone (".
\ Moreover, ANS Forth specifies that the next [THEN] ends an [IF]
\ (even if its in a '( ... )').
\ ' ( Alias ( immediate ( keep fontify happy)
\ ' \ Alias \ immediate
UNLOCK Tlast @ swap Tlast ! LOCK
\ last @ swap last !
1 cells - [struct]-voc cell+ !
\ Interpretative Structuren 30apr92py
: [defined] ( "<spaces>name" -- flag ) bl word find nip 0<> ; immediate
\G returns true if name is found in current search order
' [defined] alias defined immediate
: [undefined] ( "<spaces>name" -- flag ) postpone [defined] 0= ; immediate
\G returns false if name is found in current search order
: [IF] ( flag -- ) \ tools-ext bracket-if
\G If flag is @code{TRUE} do nothing (and therefore
\G execute subsequent words as normal). If flag is @code{FALSE},
\G parse and discard words from the parse
\G area (refilling it if necessary using
\G @code{REFILL}) including nested instances of @code{[IF]}..
\G @code{[ELSE]}.. @code{[THEN]} and @code{[IF]}.. @code{[THEN]}
\G until the balancing @code{[ELSE]} or @code{[THEN]} has been
\G parsed and discarded. Immediate word.
0= IF countif off
lookup @ [ [struct]-voc 3 cells + ] ALiteral !
[struct]-voc lookup !
THEN ; immediate
: [IFDEF] ( "<spaces>name" -- ) \ gforth bracket-if-def
\G If name is found in the current search-order, behave like
\G @code{[IF]} with a @code{TRUE} flag, otherwise behave like
\G @code{[IF]} with a @code{FALSE} flag. Immediate word.
postpone [defined] postpone [IF] ; immediate
: [IFUNDEF] ( "<spaces>name" -- ) \ gforth bracket-if-un-def
\G If name is not found in the current search-order, behave like
\G @code{[IF]} with a @code{TRUE} flag, otherwise behave like
\G @code{[IF]} with a @code{FALSE} flag. Immediate word.
postpone [defined] 0= postpone [IF] ; immediate
: [ELSE] ( -- ) \ tools-ext bracket-else
\G Parse and discard words from the parse
\G area (refilling it if necessary using
\G @code{REFILL}) including nested instances of @code{[IF]}..
\G @code{[ELSE]}.. @code{[THEN]} and @code{[IF]}.. @code{[THEN]}
\G until the balancing @code{[THEN]} has been parsed and discarded.
\G @code{[ELSE]} only gets executed if the balancing @code{[IF]}
\G was @code{TRUE}; if it was @code{FALSE}, @code{[IF]} would
\G have parsed and discarded the @code{[ELSE]}, leaving the
\G subsequent words to be executed as normal.
\G Immediate word.
0 postpone [IF] ; immediate
: [THEN] ( -- ) \ tools-ext bracket-then
\G Do nothing; used as a marker for other words to parse
\G and discard up to. Immediate word.
; immediate
: [ENDIF] ( -- ) \ gforth bracket-end-if
\G Do nothing; synonym for @code{[THEN]}
; immediate
\ Structs for interpreter 28nov92py
User (i)
: [DO] ( n-limit n-index -- ) \ gforth bracket-do
>in @ -rot
DO I (i) ! dup >r >in ! interpret r> swap +LOOP drop ;
immediate
: [?DO] ( n-limit n-index -- ) \ gforth bracket-question-do
2dup = IF 2drop postpone [ELSE] ELSE postpone [DO] THEN ;
immediate
: [+LOOP] ( n -- ) \ gforth bracket-question-plus-loop
rdrop ; immediate
: [LOOP] ( -- ) \ gforth bracket-loop
1 rdrop ; immediate
: [FOR] ( n -- ) \ gforth bracket-for
0 swap postpone [DO] ; immediate
: [NEXT] ( n -- ) \ gforth bracket-next
-1 rdrop ; immediate
:noname (i) @ ;
:noname (i) @ postpone Literal ;
interpret/compile: [I] ( -- n ) \ gforth bracket-i
: [BEGIN] ( -- ) \ gforth bracket-begin
>in @ >r BEGIN r@ >in ! interpret UNTIL rdrop ; immediate
' [+LOOP] Alias [UNTIL] ( flag -- ) \ gforth bracket-until
immediate
: [REPEAT] ( -- ) \ gforth bracket-repeat
false rdrop ; immediate
' [REPEAT] Alias [AGAIN] ( -- ) \ gforth bracket-again
immediate
: [WHILE] ( flag -- ) \ gforth bracket-while
0= IF postpone [ELSE] true rdrop 1 countif +! THEN ;
immediate
\ Warnings on
|
