[gforth] / gforth / regexp.fs  

gforth: gforth/regexp.fs


1 : pazsan 1.1 \ Regexp compile
2 :    
3 : anton 1.13 \ Copyright (C) 2005,2006,2007,2008 Free Software Foundation, Inc.
4 : anton 1.3
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 : anton 1.10 \ as published by the Free Software Foundation, either version 3
10 : anton 1.3 \ 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 : anton 1.10 \ along with this program. If not, see http://www.gnu.org/licenses/.
19 : anton 1.3
20 : pazsan 1.1 \ The idea of the parser is the following:
21 :     \ As long as there's a match, continue
22 :     \ On a mismatch, LEAVE.
23 :     \ Insert appropriate control structures on alternative branches
24 :     \ Keep the old pointer (backtracking) on the stack
25 :     \ I try to keep the syntax as close to a real regexp system as possible
26 :     \ All regexp stuff is compiled into one function as forward branching
27 :     \ state machine
28 :    
29 : pazsan 1.2 \ special control structure
30 : pazsan 1.1
31 : pazsan 1.8 : FORK ( compilation -- orig ; run-time f -- ) \ gforth
32 :     \G AHEAD-like control structure: calls the code after JOIN.
33 : pazsan 1.1 POSTPONE call >mark ; immediate restrict
34 : pazsan 1.8 : JOIN ( orig -- ) \ gforth
35 :     \G THEN-like control structure for FORK
36 :     postpone THEN ; immediate restrict
37 : pazsan 1.1
38 :     \ Charclasses
39 :    
40 :     : +bit ( addr n -- ) + 1 swap c! ;
41 :     : -bit ( addr n -- ) + 0 swap c! ;
42 :     : @+ ( addr -- n addr' ) dup @ swap cell+ ;
43 :    
44 :     0 Value cur-class
45 : pazsan 1.8 : charclass ( -- ) \ regexp-cg
46 :     \G Create a charclass
47 :     Create here dup to cur-class $100 dup allot erase ;
48 :     : +char ( char -- ) \ regexp-cg
49 :     \G add a char to the current charclass
50 :     cur-class swap +bit ;
51 :     : -char ( char -- ) \ regexp-cg
52 :     \G remove a char from the current charclass
53 :     cur-class swap -bit ;
54 :     : ..char ( start end -- ) \ regexp-cg
55 :     \G add a range of chars to the current charclass
56 :     1+ swap ?DO I +char LOOP ;
57 : pazsan 1.1 : or! ( n addr -- ) dup @ rot or swap ! ;
58 :     : and! ( n addr -- ) dup @ rot and swap ! ;
59 : pazsan 1.8 : +class ( class -- ) \ regexp-cg
60 :     \G union of charclass @var{class} and the current charclass
61 :     $100 0 ?DO @+ swap
62 :     cur-class I + or! cell +LOOP drop ;
63 :     : -class ( class -- ) \ regexp-cg
64 :     \G subtract the charclass @var{class} from the current charclass
65 :     $100 0 ?DO @+ swap invert
66 :     cur-class I + and! cell +LOOP drop ;
67 : pazsan 1.1
68 :     : char? ( addr class -- addr' flag )
69 :     >r count r> + c@ ;
70 :    
71 :     \ Charclass tests
72 :    
73 : pazsan 1.8 : c? ( addr class -- ) \ regexp-pattern
74 :     \G check @var{addr} for membership in charclass @var{class}
75 :     ]] char? 0= ?LEAVE [[ ; immediate
76 :     : -c? ( addr class -- ) \ regexp-pattern
77 :     \G check @var{addr} for not membership in charclass @var{class}
78 :     ]] char? ?LEAVE [[ ; immediate
79 : pazsan 1.1
80 :     charclass digit '0 '9 ..char
81 :     charclass blanks 0 bl ..char
82 :     \ bl +char #tab +char #cr +char #lf +char ctrl L +char
83 :     charclass letter 'a 'z ..char 'A 'Z ..char
84 :     charclass any 0 $FF ..char #lf -char
85 :    
86 : pazsan 1.8 : \d ( addr -- addr' ) \ regexp-pattern
87 :     \G check for digit
88 :     ]] digit c? [[ ; immediate
89 :     : \s ( addr -- addr' ) \ regexp-pattern
90 :     \G check for blanks
91 :     ]] blanks c? [[ ; immediate
92 :     : .? ( addr -- addr' ) \ regexp-pattern
93 :     \G check for any single charachter
94 :     ]] any c? [[ ; immediate
95 :     : -\d ( addr -- addr' ) \ regexp-pattern
96 :     \G check for not digit
97 :     ]] digit -c? [[ ; immediate
98 :     : -\s ( addr -- addr' ) \ regexp-pattern
99 :     \G check for not blank
100 :     ]] blanks -c? [[ ; immediate
101 :     : ` ( "char" -- ) \ regexp-pattern
102 :     \G check for particular char
103 : pazsan 1.1 ]] count [[ char ]] Literal <> ?LEAVE [[ ; immediate
104 : pazsan 1.17 : -` ( "char" -- ) \ regexp-pattern
105 :     \G check for particular char
106 :     ]] count [[ char ]] Literal = ?LEAVE [[ ; immediate
107 : pazsan 1.1
108 :     \ loop stack
109 :    
110 :     Variable loops $40 3 * cells allot
111 :     : 3@ ( addr -- a b c ) dup >r 2 cells + @ r> 2@ ;
112 :     : 3! ( a b c addr -- ) dup >r 2! r> 2 cells + ! ;
113 :     : loops> ( -- addr ) -3 loops +! loops @+ swap cells + 3@ ;
114 :     : >loops ( addr -- ) loops @+ swap cells + 3! 3 loops +! ;
115 :     : BEGIN, ( -- ) ]] BEGIN [[ >loops ;
116 :     : DONE, ( -- ) loops @ IF loops> ]] DONE [[ THEN ]] noop [[ ;
117 :    
118 :     \ variables
119 :    
120 :     Variable vars &18 cells allot
121 :     Variable varstack 9 cells allot
122 :     Variable varsmax
123 :     : >var ( -- addr ) vars @+ swap 2* cells +
124 :     vars @ varstack @+ swap cells + !
125 :     1 vars +! 1 varstack +! ;
126 :     : var> ( -- addr ) -1 varstack +!
127 :     varstack @+ swap cells + @
128 :     1+ 2* cells vars + ;
129 :    
130 :     \ start end
131 :    
132 :     0 Value end$
133 :     0 Value start$
134 :     : !end ( addr u -- addr ) over + to end$ dup to start$ ;
135 : pazsan 1.12 : end-rex? ( addr -- addr flag ) dup end$ u< ;
136 :     : start-rex? ( addr -- addr flag ) dup start$ u> ;
137 : pazsan 1.1 : ?end ( addr -- addr ) ]] dup end$ u> ?LEAVE [[ ; immediate
138 :    
139 :     \ start and end
140 :    
141 : pazsan 1.8 : \^ ( addr -- addr ) \ regexp-pattern
142 :     \G check for string start
143 : pazsan 1.12 ]] start-rex? ?LEAVE [[ ; immediate
144 : pazsan 1.8 : \$ ( addr -- addr ) \ regexp-pattern
145 :     \G check for string end
146 : pazsan 1.12 ]] end-rex? ?LEAVE [[ ; immediate
147 : pazsan 1.1
148 : pazsan 1.17 \ A word for string comparison
149 :    
150 :     : ,=" ( addr u -- ) tuck ]] dup SLiteral tuck compare ?LEAVE Literal + noop [[ ;
151 :     : =" ( <string>" -- ) \ regexp-pattern
152 :     \G check for string
153 :     '" parse ,=" ; immediate
154 :    
155 : pazsan 1.1 \ regexp block
156 :    
157 :     \ FORK/JOIN are like AHEAD THEN, but producing a call on AHEAD
158 :     \ instead of a jump.
159 :    
160 : pazsan 1.8 : (( ( addr u -- ) \ regexp-pattern
161 :     \G start regexp block
162 :     vars off varsmax off loops off
163 : pazsan 1.1 ]] FORK AHEAD BUT JOIN !end [[ BEGIN, ; immediate
164 : pazsan 1.8 : )) ( -- addr f ) \ regexp-pattern
165 :     \G end regexp block
166 : pazsan 1.19 ]] ?end drop true ;S [[
167 :     DONE, ]] drop false ;S THEN [[ ; immediate
168 : pazsan 1.1
169 :     \ greedy loops
170 :    
171 :     \ Idea: scan as many characters as possible, try the rest of the pattern
172 :     \ and then back off one pattern at a time
173 :    
174 :     : drops ( n -- ) 1+ cells sp@ + sp! ;
175 :    
176 : pazsan 1.8 : {** ( addr -- addr addr ) \ regexp-pattern
177 :     \G greedy zero-or-more pattern
178 : pazsan 1.1 0 ]] Literal >r BEGIN dup [[ BEGIN, ; immediate
179 : pazsan 1.8 ' {** Alias {++ ( addr -- addr addr ) \ regexp-pattern
180 :     \G greedy one-or-more pattern
181 :     immediate
182 :     : n*} ( sys n -- ) \ regexp-pattern
183 :     \G At least @var{n} pattern
184 : pazsan 1.12 >r ]] r> 1+ >r end-rex? 0= UNTIL dup [[ DONE, ]] drop [[
185 : pazsan 1.19 r@ IF r@ ]] r@ Literal u< IF r> 1+ drops false ;S THEN [[ THEN
186 : pazsan 1.1 r@ ]] r> 1+ Literal U+DO FORK BUT [[
187 : pazsan 1.19 ]] IF I' I - [[ r@ 1- ]] Literal + drops true UNLOOP ;S THEN LOOP [[
188 : pazsan 1.1 r@ IF r@ ]] Literal drops [[ THEN
189 : pazsan 1.19 rdrop ]] false ;S JOIN [[ ; immediate
190 : pazsan 1.8 : **} ( sys -- ) \ regexp-pattern
191 :     \G end of greedy zero-or-more pattern
192 :     0 postpone n*} ; immediate
193 :     : ++} ( sys -- ) \ regexp-pattern
194 :     \G end of greedy zero-or-more pattern
195 :     1 postpone n*} ; immediate
196 : pazsan 1.1
197 :     \ non-greedy loops
198 :    
199 :     \ Idea: Try to match rest of the regexp, and if that fails, try match
200 :     \ first expr and then try again rest of regexp.
201 :    
202 : pazsan 1.8 : {+ ( addr -- addr addr ) \ regexp-pattern
203 :     \G non-greedy one-or-more pattern
204 : pazsan 1.1 ]] BEGIN [[ BEGIN, ; immediate
205 : pazsan 1.8 : {* ( addr -- addr addr ) \ regexp-pattern
206 :     \G non-greedy zero-or-more pattern
207 : pazsan 1.19 ]] {+ dup FORK BUT IF drop true ;S THEN [[ ; immediate
208 : pazsan 1.8 : *} ( addr addr' -- addr' ) \ regexp-pattern
209 :     \G end of non-greedy zero-or-more pattern
210 : pazsan 1.1 ]] dup end$ u> UNTIL [[
211 : pazsan 1.19 DONE, ]] drop false ;S JOIN [[ ; immediate
212 : pazsan 1.8 : +} ( addr addr' -- addr' ) \ regexp-pattern
213 :     \G end of non-greedy one-or-more pattern
214 : pazsan 1.19 ]] dup FORK BUT IF drop true ;S [[
215 :     DONE, ]] drop false ;S THEN *} [[ ; immediate
216 : pazsan 1.1
217 : pazsan 1.8 : // ( -- ) \ regexp-pattern
218 :     \G search for string
219 :     ]] {* 1+ *} [[ ; immediate
220 : pazsan 1.1
221 :     \ alternatives
222 :    
223 :     \ idea: try to match one alternative and then the rest of regexp.
224 :     \ if that fails, jump back to second alternative
225 :    
226 : pazsan 1.18 : JOINs ( sys -- ) BEGIN dup WHILE ]] JOIN [[ REPEAT drop ;
227 : pazsan 1.1
228 : pazsan 1.8 : {{ ( addr -- addr addr ) \ regexp-pattern
229 :     \G Start of alternatives
230 :     0 ]] dup BEGIN [[ vars @ ; immediate
231 :     : || ( addr addr -- addr addr ) \ regexp-pattern
232 :     \G separator between alternatives
233 :     vars @ varsmax @ max varsmax !
234 : pazsan 1.19 ]] dup FORK IF 2drop true ;S THEN drop dup [[ >r >r >r vars !
235 : pazsan 1.1 ]] DONE drop dup [[ r> r> r> ]] BEGIN [[ vars @ ; immediate
236 : pazsan 1.8 : }} ( addr addr -- addr addr ) \ regexp-pattern
237 :     \G end of alternatives
238 :     vars @ varsmax @ max vars !
239 : pazsan 1.19 ]] dup FORK IF 2drop true ;S THEN drop dup [[ >r >r >r drop
240 : pazsan 1.18 ]] DONE drop LEAVE [[ r> r> r> JOINs ; immediate
241 : pazsan 1.1
242 :     \ match variables
243 :    
244 : pazsan 1.8 : \( ( addr -- addr ) \ regexp-pattern
245 :     \G start of matching variable; variables are referred as \\1--9
246 :     ]] dup [[
247 : pazsan 1.1 >var ]] ALiteral ! [[ ; immediate
248 : pazsan 1.8 : \) ( addr -- addr ) \ regexp-pattern
249 :     \G end of matching variable
250 :     ]] dup [[
251 : pazsan 1.1 var> ]] ALiteral ! [[ ; immediate
252 : pazsan 1.8 : \0 ( -- addr u ) \ regexp-pattern
253 :     \G the whole string
254 :     start$ end$ over - ;
255 : pazsan 1.1 : \: ( i -- )
256 :     Create 2* 1+ cells vars + ,
257 :     DOES> ( -- addr u ) @ 2@ tuck - ;
258 :     : \:s ( n -- ) 0 ?DO I \: LOOP ;
259 :     9 \:s \1 \2 \3 \4 \5 \6 \7 \8 \9
260 : pazsan 1.6
261 :     \ replacements, needs string.fs
262 :    
263 :     require string.fs
264 :    
265 :     0 Value >>ptr
266 :     0 Value <<ptr
267 :     Variable >>string
268 : pazsan 1.17 : s>> ( addr -- addr ) \ regexp-replace
269 : pazsan 1.8 \G Start replace pattern region
270 :     dup to >>ptr ;
271 :     : << ( run-addr addr u -- run-addr ) \ regexp-replace
272 :     \G Replace string from start of replace pattern region with
273 :     \G @var{addr} @var{u}
274 : pazsan 1.6 <<ptr >>ptr over - >>string $+!
275 :     >>string $+! dup to <<ptr ;
276 : pazsan 1.8 : <<" ( "string<">" -- ) \ regexp-replace
277 :     \G Replace string from start of replace pattern region with
278 :     \G @var{string}
279 :     '" parse postpone SLiteral postpone << ; immediate
280 : pazsan 1.6 : >>string@ ( -- addr u )
281 : pazsan 1.16 >>string $@ ;
282 :     : >>string0 ( addr u -- addr u ) s" " >>string $!
283 :     0 to >>ptr over to <<ptr ;
284 : pazsan 1.6 : >>next ( -- addr u ) <<ptr end$ over - ;
285 : pazsan 1.14 : >>rest ( -- ) >>next >>string $+! ;
286 :     : s// ( addr u -- ptr )
287 : pazsan 1.8 \G start search/replace loop
288 : pazsan 1.17 ]] >>string0 (( // s>> [[ ; immediate
289 :     : >> ( addr -- addr )
290 :     ]] <<ptr >>ptr u> ?LEAVE ?end [[ ; immediate
291 :     : //s ( ptr -- )
292 :     \G search end
293 :     ]] )) drop >>rest >>string@ [[ ; immediate
294 : pazsan 1.15 : //o ( ptr addr u -- addr' u' )
295 : pazsan 1.14 \G end search/replace single loop
296 : pazsan 1.17 ]] << //s [[ ; immediate
297 : pazsan 1.14 : //g ( ptr addr u -- addr' u' )
298 :     \G end search/replace all loop
299 : pazsan 1.17 ]] << LEAVE //s [[ ; immediate

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