[gforth] / gforth / regexp.fs  

gforth: gforth/regexp.fs


1 : pazsan 1.1 \ Regexp compile
2 :    
3 : anton 1.7 \ Copyright (C) 2005,2006 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 :     \ as published by the Free Software Foundation; either version 2
10 :     \ 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 :     \ along with this program; if not, write to the Free Software
19 :     \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
20 :    
21 : pazsan 1.1 \ The idea of the parser is the following:
22 :     \ As long as there's a match, continue
23 :     \ On a mismatch, LEAVE.
24 :     \ Insert appropriate control structures on alternative branches
25 :     \ Keep the old pointer (backtracking) on the stack
26 :     \ I try to keep the syntax as close to a real regexp system as possible
27 :     \ All regexp stuff is compiled into one function as forward branching
28 :     \ state machine
29 :    
30 : pazsan 1.2 \ special control structure
31 : pazsan 1.1
32 : pazsan 1.8 : FORK ( compilation -- orig ; run-time f -- ) \ gforth
33 :     \G AHEAD-like control structure: calls the code after JOIN.
34 : pazsan 1.1 POSTPONE call >mark ; immediate restrict
35 : pazsan 1.8 : JOIN ( orig -- ) \ gforth
36 :     \G THEN-like control structure for FORK
37 :     postpone THEN ; immediate restrict
38 : pazsan 1.1
39 :     \ Charclasses
40 :    
41 :     : +bit ( addr n -- ) + 1 swap c! ;
42 :     : -bit ( addr n -- ) + 0 swap c! ;
43 :     : @+ ( addr -- n addr' ) dup @ swap cell+ ;
44 :    
45 :     0 Value cur-class
46 : pazsan 1.8 : charclass ( -- ) \ regexp-cg
47 :     \G Create a charclass
48 :     Create here dup to cur-class $100 dup allot erase ;
49 :     : +char ( char -- ) \ regexp-cg
50 :     \G add a char to the current charclass
51 :     cur-class swap +bit ;
52 :     : -char ( char -- ) \ regexp-cg
53 :     \G remove a char from the current charclass
54 :     cur-class swap -bit ;
55 :     : ..char ( start end -- ) \ regexp-cg
56 :     \G add a range of chars to the current charclass
57 :     1+ swap ?DO I +char LOOP ;
58 : pazsan 1.1 : or! ( n addr -- ) dup @ rot or swap ! ;
59 :     : and! ( n addr -- ) dup @ rot and swap ! ;
60 : pazsan 1.8 : +class ( class -- ) \ regexp-cg
61 :     \G union of charclass @var{class} and the current charclass
62 :     $100 0 ?DO @+ swap
63 :     cur-class I + or! cell +LOOP drop ;
64 :     : -class ( class -- ) \ regexp-cg
65 :     \G subtract the charclass @var{class} from the current charclass
66 :     $100 0 ?DO @+ swap invert
67 :     cur-class I + and! cell +LOOP drop ;
68 : pazsan 1.1
69 :     : char? ( addr class -- addr' flag )
70 :     >r count r> + c@ ;
71 :    
72 :     \ Charclass tests
73 :    
74 : pazsan 1.8 : c? ( addr class -- ) \ regexp-pattern
75 :     \G check @var{addr} for membership in charclass @var{class}
76 :     ]] char? 0= ?LEAVE [[ ; immediate
77 :     : -c? ( addr class -- ) \ regexp-pattern
78 :     \G check @var{addr} for not membership in charclass @var{class}
79 :     ]] char? ?LEAVE [[ ; immediate
80 : pazsan 1.1
81 :     charclass digit '0 '9 ..char
82 :     charclass blanks 0 bl ..char
83 :     \ bl +char #tab +char #cr +char #lf +char ctrl L +char
84 :     charclass letter 'a 'z ..char 'A 'Z ..char
85 :     charclass any 0 $FF ..char #lf -char
86 :    
87 : pazsan 1.8 : \d ( addr -- addr' ) \ regexp-pattern
88 :     \G check for digit
89 :     ]] digit c? [[ ; immediate
90 :     : \s ( addr -- addr' ) \ regexp-pattern
91 :     \G check for blanks
92 :     ]] blanks c? [[ ; immediate
93 :     : .? ( addr -- addr' ) \ regexp-pattern
94 :     \G check for any single charachter
95 :     ]] any c? [[ ; immediate
96 :     : -\d ( addr -- addr' ) \ regexp-pattern
97 :     \G check for not digit
98 :     ]] digit -c? [[ ; immediate
99 :     : -\s ( addr -- addr' ) \ regexp-pattern
100 :     \G check for not blank
101 :     ]] blanks -c? [[ ; immediate
102 :     : ` ( "char" -- ) \ regexp-pattern
103 :     \G check for particular char
104 : pazsan 1.1 ]] count [[ char ]] Literal <> ?LEAVE [[ ; immediate
105 :    
106 :     \ A word for string comparison
107 :    
108 :     : $= ( addr1 addr2 u -- f ) tuck compare ;
109 :     : ,=" ( addr u -- ) tuck ]] dup SLiteral $= ?LEAVE Literal + noop [[ ;
110 : pazsan 1.8 : =" ( <string>" -- ) \ regexp-pattern
111 :     \G check for string
112 :     '" parse ,=" ; immediate
113 : pazsan 1.1
114 :     \ loop stack
115 :    
116 :     Variable loops $40 3 * cells allot
117 :     : 3@ ( addr -- a b c ) dup >r 2 cells + @ r> 2@ ;
118 :     : 3! ( a b c addr -- ) dup >r 2! r> 2 cells + ! ;
119 :     : loops> ( -- addr ) -3 loops +! loops @+ swap cells + 3@ ;
120 :     : >loops ( addr -- ) loops @+ swap cells + 3! 3 loops +! ;
121 :     : BEGIN, ( -- ) ]] BEGIN [[ >loops ;
122 :     : DONE, ( -- ) loops @ IF loops> ]] DONE [[ THEN ]] noop [[ ;
123 :    
124 :     \ variables
125 :    
126 :     Variable vars &18 cells allot
127 :     Variable varstack 9 cells allot
128 :     Variable varsmax
129 :     : >var ( -- addr ) vars @+ swap 2* cells +
130 :     vars @ varstack @+ swap cells + !
131 :     1 vars +! 1 varstack +! ;
132 :     : var> ( -- addr ) -1 varstack +!
133 :     varstack @+ swap cells + @
134 :     1+ 2* cells vars + ;
135 :    
136 :     \ start end
137 :    
138 :     0 Value end$
139 :     0 Value start$
140 :     : !end ( addr u -- addr ) over + to end$ dup to start$ ;
141 :     : $? ( addr -- addr flag ) dup end$ u< ;
142 :     : ^? ( addr -- addr flag ) dup start$ u> ;
143 :     : ?end ( addr -- addr ) ]] dup end$ u> ?LEAVE [[ ; immediate
144 :    
145 :     \ start and end
146 :    
147 : pazsan 1.8 : \^ ( addr -- addr ) \ regexp-pattern
148 :     \G check for string start
149 : pazsan 1.1 ]] ^? ?LEAVE [[ ; immediate
150 : pazsan 1.8 : \$ ( addr -- addr ) \ regexp-pattern
151 :     \G check for string end
152 : pazsan 1.1 ]] $? ?LEAVE [[ ; immediate
153 :    
154 :     \ regexp block
155 :    
156 :     \ FORK/JOIN are like AHEAD THEN, but producing a call on AHEAD
157 :     \ instead of a jump.
158 :    
159 : pazsan 1.8 : (( ( addr u -- ) \ regexp-pattern
160 :     \G start regexp block
161 :     vars off varsmax off loops off
162 : pazsan 1.1 ]] FORK AHEAD BUT JOIN !end [[ BEGIN, ; immediate
163 : pazsan 1.8 : )) ( -- addr f ) \ regexp-pattern
164 :     \G end regexp block
165 : pazsan 1.1 ]] ?end drop true EXIT [[
166 :     DONE, ]] drop false EXIT THEN [[ ; immediate
167 :    
168 :     \ greedy loops
169 :    
170 :     \ Idea: scan as many characters as possible, try the rest of the pattern
171 :     \ and then back off one pattern at a time
172 :    
173 :     : drops ( n -- ) 1+ cells sp@ + sp! ;
174 :    
175 : pazsan 1.8 : {** ( addr -- addr addr ) \ regexp-pattern
176 :     \G greedy zero-or-more pattern
177 : pazsan 1.1 0 ]] Literal >r BEGIN dup [[ BEGIN, ; immediate
178 : pazsan 1.8 ' {** Alias {++ ( addr -- addr addr ) \ regexp-pattern
179 :     \G greedy one-or-more pattern
180 :     immediate
181 :     : n*} ( sys n -- ) \ regexp-pattern
182 :     \G At least @var{n} pattern
183 :     >r ]] r> 1+ >r $? 0= UNTIL dup [[ DONE, ]] drop [[
184 : pazsan 1.1 r@ IF r@ ]] r@ Literal u< IF r> 1+ drops false EXIT THEN [[ THEN
185 :     r@ ]] r> 1+ Literal U+DO FORK BUT [[
186 :     ]] IF I' I - [[ r@ 1- ]] Literal + drops true UNLOOP EXIT THEN LOOP [[
187 :     r@ IF r@ ]] Literal drops [[ THEN
188 :     rdrop ]] false EXIT JOIN [[ ; immediate
189 : pazsan 1.8 : **} ( sys -- ) \ regexp-pattern
190 :     \G end of greedy zero-or-more pattern
191 :     0 postpone n*} ; immediate
192 :     : ++} ( sys -- ) \ regexp-pattern
193 :     \G end of greedy zero-or-more pattern
194 :     1 postpone n*} ; immediate
195 : pazsan 1.1
196 :     \ non-greedy loops
197 :    
198 :     \ Idea: Try to match rest of the regexp, and if that fails, try match
199 :     \ first expr and then try again rest of regexp.
200 :    
201 : pazsan 1.8 : {+ ( addr -- addr addr ) \ regexp-pattern
202 :     \G non-greedy one-or-more pattern
203 : pazsan 1.1 ]] BEGIN [[ BEGIN, ; immediate
204 : pazsan 1.8 : {* ( addr -- addr addr ) \ regexp-pattern
205 :     \G non-greedy zero-or-more pattern
206 : pazsan 1.1 ]] {+ dup FORK BUT IF drop true EXIT THEN [[ ; immediate
207 : pazsan 1.8 : *} ( addr addr' -- addr' ) \ regexp-pattern
208 :     \G end of non-greedy zero-or-more pattern
209 : pazsan 1.1 ]] dup end$ u> UNTIL [[
210 :     DONE, ]] drop false EXIT JOIN [[ ; immediate
211 : pazsan 1.8 : +} ( addr addr' -- addr' ) \ regexp-pattern
212 :     \G end of non-greedy one-or-more pattern
213 : pazsan 1.1 ]] dup FORK BUT IF drop true EXIT [[
214 :     DONE, ]] drop false EXIT THEN *} [[ ; immediate
215 :    
216 : pazsan 1.8 : // ( -- ) \ regexp-pattern
217 :     \G search for string
218 :     ]] {* 1+ *} [[ ; immediate
219 : pazsan 1.1
220 :     \ alternatives
221 :    
222 :     \ idea: try to match one alternative and then the rest of regexp.
223 :     \ if that fails, jump back to second alternative
224 :    
225 :     : THENs ( sys -- ) BEGIN dup WHILE ]] THEN [[ REPEAT drop ;
226 :    
227 : pazsan 1.8 : {{ ( addr -- addr addr ) \ regexp-pattern
228 :     \G Start of alternatives
229 :     0 ]] dup BEGIN [[ vars @ ; immediate
230 :     : || ( addr addr -- addr addr ) \ regexp-pattern
231 :     \G separator between alternatives
232 :     vars @ varsmax @ max varsmax !
233 : pazsan 1.1 ]] nip AHEAD [[ >r >r >r vars !
234 :     ]] DONE drop dup [[ r> r> r> ]] BEGIN [[ vars @ ; immediate
235 : pazsan 1.8 : }} ( addr addr -- addr addr ) \ regexp-pattern
236 :     \G end of alternatives
237 :     vars @ varsmax @ max vars !
238 : pazsan 1.1 ]] nip AHEAD [[ >r >r >r drop
239 :     ]] DONE drop LEAVE [[ r> r> r> THENs ; immediate
240 :    
241 :     \ match variables
242 :    
243 : pazsan 1.8 : \( ( addr -- addr ) \ regexp-pattern
244 :     \G start of matching variable; variables are referred as \\1--9
245 :     ]] dup [[
246 : pazsan 1.1 >var ]] ALiteral ! [[ ; immediate
247 : pazsan 1.8 : \) ( addr -- addr ) \ regexp-pattern
248 :     \G end of matching variable
249 :     ]] dup [[
250 : pazsan 1.1 var> ]] ALiteral ! [[ ; immediate
251 : pazsan 1.8 : \0 ( -- addr u ) \ regexp-pattern
252 :     \G the whole string
253 :     start$ end$ over - ;
254 : pazsan 1.1 : \: ( i -- )
255 :     Create 2* 1+ cells vars + ,
256 :     DOES> ( -- addr u ) @ 2@ tuck - ;
257 :     : \:s ( n -- ) 0 ?DO I \: LOOP ;
258 :     9 \:s \1 \2 \3 \4 \5 \6 \7 \8 \9
259 : pazsan 1.6
260 :     \ replacements, needs string.fs
261 :    
262 :     require string.fs
263 :    
264 :     0 Value >>ptr
265 :     0 Value <<ptr
266 :     Variable >>string
267 : pazsan 1.8 : >> ( addr -- addr ) \ regexp-replace
268 :     \G Start replace pattern region
269 :     dup to >>ptr ;
270 :     : << ( run-addr addr u -- run-addr ) \ regexp-replace
271 :     \G Replace string from start of replace pattern region with
272 :     \G @var{addr} @var{u}
273 : pazsan 1.6 <<ptr 0= IF start$ to <<ptr THEN
274 :     >>string @ 0= IF s" " >>string $! THEN
275 :     <<ptr >>ptr over - >>string $+!
276 :     >>string $+! dup to <<ptr ;
277 : pazsan 1.8 : <<" ( "string<">" -- ) \ regexp-replace
278 :     \G Replace string from start of replace pattern region with
279 :     \G @var{string}
280 :     '" parse postpone SLiteral postpone << ; immediate
281 : pazsan 1.6 : >>string@ ( -- addr u )
282 :     >>string $@ >>string off
283 :     0 to >>ptr 0 to <<ptr ;
284 :     : >>next ( -- addr u ) <<ptr end$ over - ;
285 : pazsan 1.8 : s// ( -- sys ) \ regexp-replace
286 :     \G start search/replace loop
287 :     ]] BEGIN [[ ; immediate
288 :     : //g ( sys -- ) \ regexp-replace
289 :     \G end search/replace loop
290 :     ]] WHILE >>next REPEAT end$ [[
291 : pazsan 1.6 s" " ]] SLiteral << >>string@ rot drop [[ ; immediate

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