[gforth] / gforth / regexp.fs  

gforth: gforth/regexp.fs


1 : pazsan 1.1 \ Regexp compile
2 :    
3 : anton 1.9 \ Copyright (C) 2005,2006,2007 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 :    
105 :     \ A word for string comparison
106 :    
107 :     : $= ( addr1 addr2 u -- f ) tuck compare ;
108 :     : ,=" ( addr u -- ) tuck ]] dup SLiteral $= ?LEAVE Literal + noop [[ ;
109 : pazsan 1.8 : =" ( <string>" -- ) \ regexp-pattern
110 :     \G check for string
111 :     '" parse ,=" ; immediate
112 : pazsan 1.1
113 :     \ loop stack
114 :    
115 :     Variable loops $40 3 * cells allot
116 :     : 3@ ( addr -- a b c ) dup >r 2 cells + @ r> 2@ ;
117 :     : 3! ( a b c addr -- ) dup >r 2! r> 2 cells + ! ;
118 :     : loops> ( -- addr ) -3 loops +! loops @+ swap cells + 3@ ;
119 :     : >loops ( addr -- ) loops @+ swap cells + 3! 3 loops +! ;
120 :     : BEGIN, ( -- ) ]] BEGIN [[ >loops ;
121 :     : DONE, ( -- ) loops @ IF loops> ]] DONE [[ THEN ]] noop [[ ;
122 :    
123 :     \ variables
124 :    
125 :     Variable vars &18 cells allot
126 :     Variable varstack 9 cells allot
127 :     Variable varsmax
128 :     : >var ( -- addr ) vars @+ swap 2* cells +
129 :     vars @ varstack @+ swap cells + !
130 :     1 vars +! 1 varstack +! ;
131 :     : var> ( -- addr ) -1 varstack +!
132 :     varstack @+ swap cells + @
133 :     1+ 2* cells vars + ;
134 :    
135 :     \ start end
136 :    
137 :     0 Value end$
138 :     0 Value start$
139 :     : !end ( addr u -- addr ) over + to end$ dup to start$ ;
140 : pazsan 1.12 : end-rex? ( addr -- addr flag ) dup end$ u< ;
141 :     : start-rex? ( addr -- addr flag ) dup start$ u> ;
142 : pazsan 1.1 : ?end ( addr -- addr ) ]] dup end$ u> ?LEAVE [[ ; immediate
143 :    
144 :     \ start and end
145 :    
146 : pazsan 1.8 : \^ ( addr -- addr ) \ regexp-pattern
147 :     \G check for string start
148 : pazsan 1.12 ]] start-rex? ?LEAVE [[ ; immediate
149 : pazsan 1.8 : \$ ( addr -- addr ) \ regexp-pattern
150 :     \G check for string end
151 : pazsan 1.12 ]] end-rex? ?LEAVE [[ ; immediate
152 : pazsan 1.1
153 :     \ regexp block
154 :    
155 :     \ FORK/JOIN are like AHEAD THEN, but producing a call on AHEAD
156 :     \ instead of a jump.
157 :    
158 : pazsan 1.8 : (( ( addr u -- ) \ regexp-pattern
159 :     \G start regexp block
160 :     vars off varsmax off loops off
161 : pazsan 1.1 ]] FORK AHEAD BUT JOIN !end [[ BEGIN, ; immediate
162 : pazsan 1.8 : )) ( -- addr f ) \ regexp-pattern
163 :     \G end regexp block
164 : pazsan 1.1 ]] ?end drop true EXIT [[
165 :     DONE, ]] drop false EXIT THEN [[ ; immediate
166 :    
167 :     \ greedy loops
168 :    
169 :     \ Idea: scan as many characters as possible, try the rest of the pattern
170 :     \ and then back off one pattern at a time
171 :    
172 :     : drops ( n -- ) 1+ cells sp@ + sp! ;
173 :    
174 : pazsan 1.8 : {** ( addr -- addr addr ) \ regexp-pattern
175 :     \G greedy zero-or-more pattern
176 : pazsan 1.1 0 ]] Literal >r BEGIN dup [[ BEGIN, ; immediate
177 : pazsan 1.8 ' {** Alias {++ ( addr -- addr addr ) \ regexp-pattern
178 :     \G greedy one-or-more pattern
179 :     immediate
180 :     : n*} ( sys n -- ) \ regexp-pattern
181 :     \G At least @var{n} pattern
182 : pazsan 1.12 >r ]] r> 1+ >r end-rex? 0= UNTIL dup [[ DONE, ]] drop [[
183 : pazsan 1.1 r@ IF r@ ]] r@ Literal u< IF r> 1+ drops false EXIT THEN [[ THEN
184 :     r@ ]] r> 1+ Literal U+DO FORK BUT [[
185 :     ]] IF I' I - [[ r@ 1- ]] Literal + drops true UNLOOP EXIT THEN LOOP [[
186 :     r@ IF r@ ]] Literal drops [[ THEN
187 :     rdrop ]] false EXIT JOIN [[ ; immediate
188 : pazsan 1.8 : **} ( sys -- ) \ regexp-pattern
189 :     \G end of greedy zero-or-more pattern
190 :     0 postpone n*} ; immediate
191 :     : ++} ( sys -- ) \ regexp-pattern
192 :     \G end of greedy zero-or-more pattern
193 :     1 postpone n*} ; immediate
194 : pazsan 1.1
195 :     \ non-greedy loops
196 :    
197 :     \ Idea: Try to match rest of the regexp, and if that fails, try match
198 :     \ first expr and then try again rest of regexp.
199 :    
200 : pazsan 1.8 : {+ ( addr -- addr addr ) \ regexp-pattern
201 :     \G non-greedy one-or-more pattern
202 : pazsan 1.1 ]] BEGIN [[ BEGIN, ; immediate
203 : pazsan 1.8 : {* ( addr -- addr addr ) \ regexp-pattern
204 :     \G non-greedy zero-or-more pattern
205 : pazsan 1.1 ]] {+ dup FORK BUT IF drop true EXIT THEN [[ ; immediate
206 : pazsan 1.8 : *} ( addr addr' -- addr' ) \ regexp-pattern
207 :     \G end of non-greedy zero-or-more pattern
208 : pazsan 1.1 ]] dup end$ u> UNTIL [[
209 :     DONE, ]] drop false EXIT JOIN [[ ; immediate
210 : pazsan 1.8 : +} ( addr addr' -- addr' ) \ regexp-pattern
211 :     \G end of non-greedy one-or-more pattern
212 : pazsan 1.1 ]] dup FORK BUT IF drop true EXIT [[
213 :     DONE, ]] drop false EXIT THEN *} [[ ; immediate
214 :    
215 : pazsan 1.8 : // ( -- ) \ regexp-pattern
216 :     \G search for string
217 :     ]] {* 1+ *} [[ ; immediate
218 : pazsan 1.1
219 :     \ alternatives
220 :    
221 :     \ idea: try to match one alternative and then the rest of regexp.
222 :     \ if that fails, jump back to second alternative
223 :    
224 :     : THENs ( sys -- ) BEGIN dup WHILE ]] THEN [[ REPEAT drop ;
225 :    
226 : pazsan 1.8 : {{ ( addr -- addr addr ) \ regexp-pattern
227 :     \G Start of alternatives
228 :     0 ]] dup BEGIN [[ vars @ ; immediate
229 :     : || ( addr addr -- addr addr ) \ regexp-pattern
230 :     \G separator between alternatives
231 :     vars @ varsmax @ max varsmax !
232 : pazsan 1.1 ]] nip AHEAD [[ >r >r >r vars !
233 :     ]] DONE drop dup [[ r> r> r> ]] BEGIN [[ vars @ ; immediate
234 : pazsan 1.8 : }} ( addr addr -- addr addr ) \ regexp-pattern
235 :     \G end of alternatives
236 :     vars @ varsmax @ max vars !
237 : pazsan 1.1 ]] nip AHEAD [[ >r >r >r drop
238 :     ]] DONE drop LEAVE [[ r> r> r> THENs ; immediate
239 :    
240 :     \ match variables
241 :    
242 : pazsan 1.8 : \( ( addr -- addr ) \ regexp-pattern
243 :     \G start of matching variable; variables are referred as \\1--9
244 :     ]] dup [[
245 : pazsan 1.1 >var ]] ALiteral ! [[ ; immediate
246 : pazsan 1.8 : \) ( addr -- addr ) \ regexp-pattern
247 :     \G end of matching variable
248 :     ]] dup [[
249 : pazsan 1.1 var> ]] ALiteral ! [[ ; immediate
250 : pazsan 1.8 : \0 ( -- addr u ) \ regexp-pattern
251 :     \G the whole string
252 :     start$ end$ over - ;
253 : pazsan 1.1 : \: ( i -- )
254 :     Create 2* 1+ cells vars + ,
255 :     DOES> ( -- addr u ) @ 2@ tuck - ;
256 :     : \:s ( n -- ) 0 ?DO I \: LOOP ;
257 :     9 \:s \1 \2 \3 \4 \5 \6 \7 \8 \9
258 : pazsan 1.6
259 :     \ replacements, needs string.fs
260 :    
261 :     require string.fs
262 :    
263 :     0 Value >>ptr
264 :     0 Value <<ptr
265 :     Variable >>string
266 : pazsan 1.8 : >> ( addr -- addr ) \ regexp-replace
267 :     \G Start replace pattern region
268 :     dup to >>ptr ;
269 :     : << ( run-addr addr u -- run-addr ) \ regexp-replace
270 :     \G Replace string from start of replace pattern region with
271 :     \G @var{addr} @var{u}
272 : pazsan 1.6 <<ptr 0= IF start$ to <<ptr THEN
273 :     >>string @ 0= IF s" " >>string $! THEN
274 :     <<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 :     >>string $@ >>string off
282 :     0 to >>ptr 0 to <<ptr ;
283 :     : >>next ( -- addr u ) <<ptr end$ over - ;
284 : pazsan 1.8 : s// ( -- sys ) \ regexp-replace
285 :     \G start search/replace loop
286 :     ]] BEGIN [[ ; immediate
287 :     : //g ( sys -- ) \ regexp-replace
288 :     \G end search/replace loop
289 :     ]] WHILE >>next REPEAT end$ [[
290 : pazsan 1.6 s" " ]] SLiteral << >>string@ rot drop [[ ; immediate

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