1: \ Copyright (C) 1995,1998,2000,2003,2005,2007,2009,2010,2012 Free Software Foundation, Inc.
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 3
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, see http://www.gnu.org/licenses/.
17:
18: Warnings off
19:
20: Variable countif
21:
22: : dummy ; immediate
23: : >exec >r ; restrict ( :-)
24: : scanIF f83find dup 0= IF drop ['] dummy >head-noprim THEN ;
25:
26: Create [struct]-search ' scanIF A, ' (reveal) A, ' drop A, ' drop A,
27: Create [struct]-voc [struct]-search A,
28: NIL A, NIL A, NIL A,
29:
30: : ?if countif @ 0<
31: IF [ [struct]-voc 3 cells + ] ALiteral @ lookup ! THEN ;
32:
33: UNLOCK Tlast @ TNIL Tlast ! LOCK
34: \ last @ 0 last !
35:
36: : [IF]
37: 1 countif +! ?if ; immediate
38: : [THEN]
39: -1 countif +! ?if ; immediate
40: : [ELSE]
41: postpone [THEN] postpone [IF] ; immediate
42:
43: ' [IF] Alias [IFDEF] immediate
44: ' [IF] Alias [IFUNDEF] immediate
45: ' [THEN] Alias [ENDIF] immediate
46: ' [IF] Alias [BEGIN] immediate
47: ' [IF] Alias [WHILE] immediate
48: ' [THEN] Alias [UNTIL] immediate
49: ' [THEN] Alias [AGAIN] immediate
50: ' [IF] Alias [DO] immediate
51: ' [IF] Alias [?DO] immediate
52: ' [THEN] Alias [LOOP] immediate
53: ' [THEN] Alias [+LOOP] immediate
54: : [REPEAT] postpone [AGAIN] postpone [THEN] ;
55: immediate
56: \ The following was too smart for its own good; consider "postpone (".
57: \ Moreover, ANS Forth specifies that the next [THEN] ends an [IF]
58: \ (even if its in a '( ... )').
59:
60: \ ' ( Alias ( immediate ( keep fontify happy)
61: \ ' \ Alias \ immediate
62:
63: UNLOCK Tlast @ swap Tlast ! LOCK
64: \ last @ swap last !
65: 1 cells - [struct]-voc cell+ !
66:
67: \ Interpretative Structuren 30apr92py
68:
69: : [defined] ( "<spaces>name" -- flag ) parse-name find-name 0<> ; immediate
70: \G returns true if name is found in current search order
71: ' [defined] alias defined immediate
72: : [undefined] ( "<spaces>name" -- flag ) postpone [defined] 0= ; immediate
73: \G returns false if name is found in current search order
74:
75: : [IF] ( flag -- ) \ tools-ext bracket-if
76: \G If flag is @code{TRUE} do nothing (and therefore
77: \G execute subsequent words as normal). If flag is @code{FALSE},
78: \G parse and discard words from the parse
79: \G area (refilling it if necessary using
80: \G @code{REFILL}) including nested instances of @code{[IF]}..
81: \G @code{[ELSE]}.. @code{[THEN]} and @code{[IF]}.. @code{[THEN]}
82: \G until the balancing @code{[ELSE]} or @code{[THEN]} has been
83: \G parsed and discarded. Immediate word.
84: 0= IF countif off
85: lookup @ [ [struct]-voc 3 cells + ] ALiteral !
86: [struct]-voc lookup !
87: THEN ; immediate
88:
89: : [IFDEF] ( "<spaces>name" -- ) \ gforth bracket-if-def
90: \G If name is found in the current search-order, behave like
91: \G @code{[IF]} with a @code{TRUE} flag, otherwise behave like
92: \G @code{[IF]} with a @code{FALSE} flag. Immediate word.
93: postpone [defined] postpone [IF] ; immediate
94:
95: : [IFUNDEF] ( "<spaces>name" -- ) \ gforth bracket-if-un-def
96: \G If name is not found in the current search-order, behave like
97: \G @code{[IF]} with a @code{TRUE} flag, otherwise behave like
98: \G @code{[IF]} with a @code{FALSE} flag. Immediate word.
99: postpone [defined] 0= postpone [IF] ; immediate
100:
101: : [ELSE] ( -- ) \ tools-ext bracket-else
102: \G Parse and discard words from the parse
103: \G area (refilling it if necessary using
104: \G @code{REFILL}) including nested instances of @code{[IF]}..
105: \G @code{[ELSE]}.. @code{[THEN]} and @code{[IF]}.. @code{[THEN]}
106: \G until the balancing @code{[THEN]} has been parsed and discarded.
107: \G @code{[ELSE]} only gets executed if the balancing @code{[IF]}
108: \G was @code{TRUE}; if it was @code{FALSE}, @code{[IF]} would
109: \G have parsed and discarded the @code{[ELSE]}, leaving the
110: \G subsequent words to be executed as normal.
111: \G Immediate word.
112: 0 postpone [IF] ; immediate
113:
114: : [THEN] ( -- ) \ tools-ext bracket-then
115: \G Do nothing; used as a marker for other words to parse
116: \G and discard up to. Immediate word.
117: ; immediate
118:
119: : [ENDIF] ( -- ) \ gforth bracket-end-if
120: \G Do nothing; synonym for @code{[THEN]}
121: ; immediate
122:
123: \ Structs for interpreter 28nov92py
124:
125: User (i)
126:
127: : [DO] ( n-limit n-index -- ) \ gforth bracket-do
128: >in @ -rot
129: DO I (i) ! dup >r >in ! interpret r> swap +LOOP drop ;
130: immediate
131:
132: : [?DO] ( n-limit n-index -- ) \ gforth bracket-question-do
133: 2dup = IF 2drop postpone [ELSE] ELSE postpone [DO] THEN ;
134: immediate
135:
136: : [+LOOP] ( n -- ) \ gforth bracket-question-plus-loop
137: rdrop lp+ ; immediate
138:
139: : [LOOP] ( -- ) \ gforth bracket-loop
140: 1 rdrop lp+ ; immediate
141:
142: : [FOR] ( n -- ) \ gforth bracket-for
143: 0 swap postpone [DO] ; immediate
144:
145: : [NEXT] ( n -- ) \ gforth bracket-next
146: -1 rdrop lp+ ; immediate
147:
148: :noname (i) @ ;
149: :noname (i) @ postpone Literal ;
150: interpret/compile: [I] ( -- n ) \ gforth bracket-i
151:
152: : [BEGIN] ( -- ) \ gforth bracket-begin
153: >in @ >r BEGIN r@ >in ! interpret UNTIL rdrop lp+ ; immediate
154:
155: ' [+LOOP] Alias [UNTIL] ( flag -- ) \ gforth bracket-until
156: immediate
157:
158: : [REPEAT] ( -- ) \ gforth bracket-repeat
159: false rdrop lp+ ; immediate
160:
161: ' [REPEAT] Alias [AGAIN] ( -- ) \ gforth bracket-again
162: immediate
163:
164: : [WHILE] ( flag -- ) \ gforth bracket-while
165: 0= IF postpone [ELSE] true rdrop lp+ 1 countif +! THEN ;
166: immediate
167:
168: \ Warnings on
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