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[emacs.git] / lisp / emacs-lisp / rx.el
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1 ;;; rx.el --- sexp notation for regular expressions
3 ;; Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 ;; Author: Gerd Moellmann <gerd@gnu.org>
6 ;; Maintainer: emacs-devel@gnu.org
7 ;; Keywords: strings, regexps, extensions
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software: you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation, either version 3 of the License, or
14 ;; (at your option) any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
24 ;;; Commentary:
26 ;; This is another implementation of sexp-form regular expressions.
27 ;; It was unfortunately written without being aware of the Sregex
28 ;; package coming with Emacs, but as things stand, Rx completely
29 ;; covers all regexp features, which Sregex doesn't, doesn't suffer
30 ;; from the bugs mentioned in the commentary section of Sregex, and
31 ;; uses a nicer syntax (IMHO, of course :-).
33 ;; This significantly extended version of the original, is almost
34 ;; compatible with Sregex. The only incompatibility I (fx) know of is
35 ;; that the `repeat' form can't have multiple regexp args.
37 ;; Now alternative forms are provided for a degree of compatibility
38 ;; with Olin Shivers' attempted definitive SRE notation. SRE forms
39 ;; not catered for include: dsm, uncase, w/case, w/nocase, ,@<exp>,
40 ;; ,<exp>, (word ...), word+, posix-string, and character class forms.
41 ;; Some forms are inconsistent with SRE, either for historical reasons
42 ;; or because of the implementation -- simple translation into Emacs
43 ;; regexp strings. These include: any, word. Also, case-sensitivity
44 ;; and greediness are controlled by variables external to the regexp,
45 ;; and you need to feed the forms to the `posix-' functions to get
46 ;; SRE's POSIX semantics. There are probably more difficulties.
48 ;; Rx translates a sexp notation for regular expressions into the
49 ;; usual string notation. The translation can be done at compile-time
50 ;; by using the `rx' macro. It can be done at run-time by calling
51 ;; function `rx-to-string'. See the documentation of `rx' for a
52 ;; complete description of the sexp notation.
53 ;;
54 ;; Some examples of string regexps and their sexp counterparts:
55 ;;
56 ;; "^[a-z]*"
57 ;; (rx (and line-start (0+ (in "a-z"))))
58 ;;
59 ;; "\n[^ \t]"
60 ;; (rx (and "\n" (not blank))), or
61 ;; (rx (and "\n" (not (any " \t"))))
62 ;;
63 ;; "\\*\\*\\* EOOH \\*\\*\\*\n"
64 ;; (rx "*** EOOH ***\n")
65 ;;
66 ;; "\\<\\(catch\\|finally\\)\\>[^_]"
67 ;; (rx (and word-start (submatch (or "catch" "finally")) word-end
68 ;; (not (any ?_))))
69 ;;
70 ;; "[ \t\n]*:\\([^:]+\\|$\\)"
71 ;; (rx (and (zero-or-more (in " \t\n")) ":"
72 ;; (submatch (or line-end (one-or-more (not (any ?:)))))))
73 ;;
74 ;; "^content-transfer-encoding:\\(\n?[\t ]\\)*quoted-printable\\(\n?[\t ]\\)*"
75 ;; (rx (and line-start
76 ;; "content-transfer-encoding:"
77 ;; (+ (? ?\n)) blank
78 ;; "quoted-printable"
79 ;; (+ (? ?\n)) blank))
80 ;;
81 ;; (concat "^\\(?:" something-else "\\)")
82 ;; (rx (and line-start (eval something-else))), statically or
83 ;; (rx-to-string '(and line-start ,something-else)), dynamically.
84 ;;
85 ;; (regexp-opt '(STRING1 STRING2 ...))
86 ;; (rx (or STRING1 STRING2 ...)), or in other words, `or' automatically
87 ;; calls `regexp-opt' as needed.
88 ;;
89 ;; "^;;\\s-*\n\\|^\n"
90 ;; (rx (or (and line-start ";;" (0+ space) ?\n)
91 ;; (and line-start ?\n)))
92 ;;
93 ;; "\\$[I]d: [^ ]+ \\([^ ]+\\) "
94 ;; (rx (and "$Id: "
95 ;; (1+ (not (in " ")))
96 ;; " "
97 ;; (submatch (1+ (not (in " "))))
98 ;; " "))
99 ;;
100 ;; "\\\\\\\\\\[\\w+"
101 ;; (rx (and ?\\ ?\\ ?\[ (1+ word)))
102 ;;
103 ;; etc.
105 ;;; History:
106 ;;
108 ;;; Code:
110 ;; FIXME: support macros.
112 (defvar rx-constituents ;Not `const' because some modes extend it.
113 '((and . (rx-and 1 nil))
114 (seq . and) ; SRE
115 (: . and) ; SRE
116 (sequence . and) ; sregex
117 (or . (rx-or 1 nil))
118 (| . or) ; SRE
119 (not-newline . ".")
120 (nonl . not-newline) ; SRE
121 (anything . (rx-anything 0 nil))
122 (any . (rx-any 1 nil rx-check-any)) ; inconsistent with SRE
123 (any . ".") ; sregex
124 (in . any)
125 (char . any) ; sregex
126 (not-char . (rx-not-char 1 nil rx-check-any)) ; sregex
127 (not . (rx-not 1 1 rx-check-not))
128 (repeat . (rx-repeat 2 nil))
129 (= . (rx-= 2 nil)) ; SRE
130 (>= . (rx->= 2 nil)) ; SRE
131 (** . (rx-** 2 nil)) ; SRE
132 (submatch . (rx-submatch 1 nil)) ; SRE
133 (group . submatch) ; sregex
134 (submatch-n . (rx-submatch-n 2 nil))
135 (group-n . submatch-n)
136 (zero-or-more . (rx-kleene 1 nil))
137 (one-or-more . (rx-kleene 1 nil))
138 (zero-or-one . (rx-kleene 1 nil))
139 (\? . zero-or-one) ; SRE
140 (\?? . zero-or-one)
141 (* . zero-or-more) ; SRE
142 (*? . zero-or-more)
143 (0+ . zero-or-more)
144 (+ . one-or-more) ; SRE
145 (+? . one-or-more)
146 (1+ . one-or-more)
147 (optional . zero-or-one)
148 (opt . zero-or-one) ; sregex
149 (minimal-match . (rx-greedy 1 1))
150 (maximal-match . (rx-greedy 1 1))
151 (backref . (rx-backref 1 1 rx-check-backref))
152 (line-start . "^")
153 (bol . line-start) ; SRE
154 (line-end . "$")
155 (eol . line-end) ; SRE
156 (string-start . "\\`")
157 (bos . string-start) ; SRE
158 (bot . string-start) ; sregex
159 (string-end . "\\'")
160 (eos . string-end) ; SRE
161 (eot . string-end) ; sregex
162 (buffer-start . "\\`")
163 (buffer-end . "\\'")
164 (point . "\\=")
165 (word-start . "\\<")
166 (bow . word-start) ; SRE
167 (word-end . "\\>")
168 (eow . word-end) ; SRE
169 (word-boundary . "\\b")
170 (not-word-boundary . "\\B") ; sregex
171 (symbol-start . "\\_<")
172 (symbol-end . "\\_>")
173 (syntax . (rx-syntax 1 1))
174 (not-syntax . (rx-not-syntax 1 1)) ; sregex
175 (category . (rx-category 1 1 rx-check-category))
176 (eval . (rx-eval 1 1))
177 (regexp . (rx-regexp 1 1 stringp))
178 (regex . regexp) ; sregex
179 (digit . "[[:digit:]]")
180 (numeric . digit) ; SRE
181 (num . digit) ; SRE
182 (control . "[[:cntrl:]]") ; SRE
183 (cntrl . control) ; SRE
184 (hex-digit . "[[:xdigit:]]") ; SRE
185 (hex . hex-digit) ; SRE
186 (xdigit . hex-digit) ; SRE
187 (blank . "[[:blank:]]") ; SRE
188 (graphic . "[[:graph:]]") ; SRE
189 (graph . graphic) ; SRE
190 (printing . "[[:print:]]") ; SRE
191 (print . printing) ; SRE
192 (alphanumeric . "[[:alnum:]]") ; SRE
193 (alnum . alphanumeric) ; SRE
194 (letter . "[[:alpha:]]")
195 (alphabetic . letter) ; SRE
196 (alpha . letter) ; SRE
197 (ascii . "[[:ascii:]]") ; SRE
198 (nonascii . "[[:nonascii:]]")
199 (lower . "[[:lower:]]") ; SRE
200 (lower-case . lower) ; SRE
201 (punctuation . "[[:punct:]]") ; SRE
202 (punct . punctuation) ; SRE
203 (space . "[[:space:]]") ; SRE
204 (whitespace . space) ; SRE
205 (white . space) ; SRE
206 (upper . "[[:upper:]]") ; SRE
207 (upper-case . upper) ; SRE
208 (word . "[[:word:]]") ; inconsistent with SRE
209 (wordchar . word) ; sregex
210 (not-wordchar . "\\W"))
211 "Alist of sexp form regexp constituents.
212 Each element of the alist has the form (SYMBOL . DEFN).
213 SYMBOL is a valid constituent of sexp regular expressions.
214 If DEFN is a string, SYMBOL is translated into DEFN.
215 If DEFN is a symbol, use the definition of DEFN, recursively.
216 Otherwise, DEFN must be a list (FUNCTION MIN-ARGS MAX-ARGS PREDICATE).
217 FUNCTION is used to produce code for SYMBOL. MIN-ARGS and MAX-ARGS
218 are the minimum and maximum number of arguments the function-form
219 sexp constituent SYMBOL may have in sexp regular expressions.
220 MAX-ARGS nil means no limit. PREDICATE, if specified, means that
221 all arguments must satisfy PREDICATE.")
224 (defconst rx-syntax
225 '((whitespace . ?-)
226 (punctuation . ?.)
227 (word . ?w)
228 (symbol . ?_)
229 (open-parenthesis . ?\()
230 (close-parenthesis . ?\))
231 (expression-prefix . ?\')
232 (string-quote . ?\")
233 (paired-delimiter . ?$)
234 (escape . ?\\)
235 (character-quote . ?/)
236 (comment-start . ?<)
237 (comment-end . ?>)
238 (string-delimiter . ?|)
239 (comment-delimiter . ?!))
240 "Alist mapping Rx syntax symbols to syntax characters.
241 Each entry has the form (SYMBOL . CHAR), where SYMBOL is a valid
242 symbol in `(syntax SYMBOL)', and CHAR is the syntax character
243 corresponding to SYMBOL, as it would be used with \\s or \\S in
244 regular expressions.")
247 (defconst rx-categories
248 '((consonant . ?0)
249 (base-vowel . ?1)
250 (upper-diacritical-mark . ?2)
251 (lower-diacritical-mark . ?3)
252 (tone-mark . ?4)
253 (symbol . ?5)
254 (digit . ?6)
255 (vowel-modifying-diacritical-mark . ?7)
256 (vowel-sign . ?8)
257 (semivowel-lower . ?9)
258 (not-at-end-of-line . ?<)
259 (not-at-beginning-of-line . ?>)
260 (alpha-numeric-two-byte . ?A)
261 (chinese-two-byte . ?C)
262 (chinse-two-byte . ?C) ;; A typo in Emacs 21.1-24.3.
263 (greek-two-byte . ?G)
264 (japanese-hiragana-two-byte . ?H)
265 (indian-two-byte . ?I)
266 (japanese-katakana-two-byte . ?K)
267 (korean-hangul-two-byte . ?N)
268 (cyrillic-two-byte . ?Y)
269 (combining-diacritic . ?^)
270 (ascii . ?a)
271 (arabic . ?b)
272 (chinese . ?c)
273 (ethiopic . ?e)
274 (greek . ?g)
275 (korean . ?h)
276 (indian . ?i)
277 (japanese . ?j)
278 (japanese-katakana . ?k)
279 (latin . ?l)
280 (lao . ?o)
281 (tibetan . ?q)
282 (japanese-roman . ?r)
283 (thai . ?t)
284 (vietnamese . ?v)
285 (hebrew . ?w)
286 (cyrillic . ?y)
287 (can-break . ?|))
288 "Alist mapping symbols to category characters.
289 Each entry has the form (SYMBOL . CHAR), where SYMBOL is a valid
290 symbol in `(category SYMBOL)', and CHAR is the category character
291 corresponding to SYMBOL, as it would be used with `\\c' or `\\C' in
292 regular expression strings.")
295 (defvar rx-greedy-flag t
296 "Non-nil means produce greedy regular expressions for `zero-or-one',
297 `zero-or-more', and `one-or-more'. Dynamically bound.")
300 (defun rx-info (op head)
301 "Return parsing/code generation info for OP.
302 If OP is the space character ASCII 32, return info for the symbol `?'.
303 If OP is the character `?', return info for the symbol `??'.
304 See also `rx-constituents'.
305 If HEAD is non-nil, then OP is the head of a sexp, otherwise it's
306 a standalone symbol."
307 (cond ((eq op ? ) (setq op '\?))
308 ((eq op ??) (setq op '\??)))
309 (let (old-op)
310 (while (and (not (null op)) (symbolp op))
311 (setq old-op op)
312 (setq op (cdr (assq op rx-constituents)))
313 (when (if head (stringp op) (consp op))
314 ;; We found something but of the wrong kind. Let's look for an
315 ;; alternate definition for the other case.
316 (let ((new-op
317 (cdr (assq old-op (cdr (memq (assq old-op rx-constituents)
318 rx-constituents))))))
319 (if (and new-op (not (if head (stringp new-op) (consp new-op))))
320 (setq op new-op))))))
321 op)
324 (defun rx-check (form)
325 "Check FORM according to its car's parsing info."
326 (unless (listp form)
327 (error "rx `%s' needs argument(s)" form))
328 (let* ((rx (rx-info (car form) 'head))
329 (nargs (1- (length form)))
330 (min-args (nth 1 rx))
331 (max-args (nth 2 rx))
332 (type-pred (nth 3 rx)))
333 (when (and (not (null min-args))
334 (< nargs min-args))
335 (error "rx form `%s' requires at least %d args"
336 (car form) min-args))
337 (when (and (not (null max-args))
338 (> nargs max-args))
339 (error "rx form `%s' accepts at most %d args"
340 (car form) max-args))
341 (when (not (null type-pred))
342 (dolist (sub-form (cdr form))
343 (unless (funcall type-pred sub-form)
344 (error "rx form `%s' requires args satisfying `%s'"
345 (car form) type-pred))))))
348 (defun rx-group-if (regexp group)
349 "Put shy groups around REGEXP if seemingly necessary when GROUP
350 is non-nil."
351 (cond
352 ;; for some repetition
353 ((eq group '*) (if (rx-atomic-p regexp) (setq group nil)))
354 ;; for concatenation
355 ((eq group ':)
356 (if (rx-atomic-p
357 (if (string-match
358 "\\(?:[?*+]\\??\\|\\\\{[0-9]*,?[0-9]*\\\\}\\)\\'" regexp)
359 (substring regexp 0 (match-beginning 0))
360 regexp))
361 (setq group nil)))
362 ;; for OR
363 ((eq group '|) (setq group nil))
364 ;; do anyway
365 ((eq group t))
366 ((rx-atomic-p regexp t) (setq group nil)))
367 (if group
368 (concat "\\(?:" regexp "\\)")
369 regexp))
372 (defvar rx-parent)
373 ;; dynamically bound in some functions.
376 (defun rx-and (form)
377 "Parse and produce code from FORM.
378 FORM is of the form `(and FORM1 ...)'."
379 (rx-check form)
380 (rx-group-if
381 (mapconcat (lambda (x) (rx-form x ':)) (cdr form) nil)
382 (and (memq rx-parent '(* t)) rx-parent)))
385 (defun rx-or (form)
386 "Parse and produce code from FORM, which is `(or FORM1 ...)'."
387 (rx-check form)
388 (rx-group-if
389 (if (memq nil (mapcar 'stringp (cdr form)))
390 (mapconcat (lambda (x) (rx-form x '|)) (cdr form) "\\|")
391 (regexp-opt (cdr form)))
392 (and (memq rx-parent '(: * t)) rx-parent)))
395 (defun rx-anything (form)
396 "Match any character."
397 (if (consp form)
398 (error "rx `anything' syntax error: %s" form))
399 (rx-or (list 'or 'not-newline ?\n)))
402 (defun rx-any-delete-from-range (char ranges)
403 "Delete by side effect character CHAR from RANGES.
404 Only both edges of each range is checked."
405 (let (m)
406 (cond
407 ((memq char ranges) (setq ranges (delq char ranges)))
408 ((setq m (assq char ranges))
409 (if (eq (1+ char) (cdr m))
410 (setcar (memq m ranges) (1+ char))
411 (setcar m (1+ char))))
412 ((setq m (rassq char ranges))
413 (if (eq (1- char) (car m))
414 (setcar (memq m ranges) (1- char))
415 (setcdr m (1- char)))))
416 ranges))
419 (defun rx-any-condense-range (args)
420 "Condense by side effect ARGS as range for Rx `any'."
421 (let (str
422 l)
423 ;; set STR list of all strings
424 ;; set L list of all ranges
425 (mapc (lambda (e) (cond ((stringp e) (push e str))
426 ((numberp e) (push (cons e e) l))
427 (t (push e l))))
428 args)
429 ;; condense overlapped ranges in L
430 (let ((tail (setq l (sort l #'car-less-than-car)))
431 d)
432 (while (setq d (cdr tail))
433 (if (>= (cdar tail) (1- (caar d)))
434 (progn
435 (setcdr (car tail) (max (cdar tail) (cdar d)))
436 (setcdr tail (cdr d)))
437 (setq tail d))))
438 ;; Separate small ranges to single number, and delete dups.
439 (nconc
440 (apply #'nconc
441 (mapcar (lambda (e)
442 (cond
443 ((= (car e) (cdr e)) (list (car e)))
444 ((= (1+ (car e)) (cdr e)) (list (car e) (cdr e)))
445 ((list e))))
446 l))
447 (delete-dups str))))
450 (defun rx-check-any-string (str)
451 "Check string argument STR for Rx `any'."
452 (let ((i 0)
453 c1 c2 l)
454 (if (= 0 (length str))
455 (error "String arg for Rx `any' must not be empty"))
456 (while (string-match ".-." str i)
457 ;; string before range: convert it to characters
458 (if (< i (match-beginning 0))
459 (setq l (nconc
461 (append (substring str i (match-beginning 0)) nil))))
462 ;; range
463 (setq i (match-end 0)
464 c1 (aref str (match-beginning 0))
465 c2 (aref str (1- i)))
466 (cond
467 ((< c1 c2) (setq l (nconc l (list (cons c1 c2)))))
468 ((= c1 c2) (setq l (nconc l (list c1))))))
469 ;; rest?
470 (if (< i (length str))
471 (setq l (nconc l (append (substring str i) nil))))
472 l))
475 (defun rx-check-any (arg)
476 "Check arg ARG for Rx `any'."
477 (cond
478 ((integerp arg) (list arg))
479 ((symbolp arg)
480 (let ((translation (condition-case nil
481 (rx-form arg)
482 (error nil))))
483 (if (or (null translation)
484 (null (string-match "\\`\\[\\[:[-a-z]+:\\]\\]\\'" translation)))
485 (error "Invalid char class `%s' in Rx `any'" arg))
486 (list (substring translation 1 -1)))) ; strip outer brackets
487 ((and (integerp (car-safe arg)) (integerp (cdr-safe arg)))
488 (list arg))
489 ((stringp arg) (rx-check-any-string arg))
490 ((error
491 "rx `any' requires string, character, char pair or char class args"))))
494 (defun rx-any (form)
495 "Parse and produce code from FORM, which is `(any ARG ...)'.
496 ARG is optional."
497 (rx-check form)
498 (let* ((args (rx-any-condense-range
499 (apply
500 #'nconc
501 (mapcar #'rx-check-any (cdr form)))))
503 s)
504 (cond
505 ;; single close bracket
506 ;; => "[]...-]" or "[]...--.]"
507 ((memq ?\] args)
508 ;; set ] at the beginning
509 (setq args (cons ?\] (delq ?\] args)))
510 ;; set - at the end
511 (if (or (memq ?- args) (assq ?- args))
512 (setq args (nconc (rx-any-delete-from-range ?- args)
513 (list ?-)))))
514 ;; close bracket starts a range
515 ;; => "[]-....-]" or "[]-.--....]"
516 ((setq m (assq ?\] args))
517 ;; bring it to the beginning
518 (setq args (cons m (delq m args)))
519 (cond ((memq ?- args)
520 ;; to the end
521 (setq args (nconc (delq ?- args) (list ?-))))
522 ((setq m (assq ?- args))
523 ;; next to the bracket's range, make the second range
524 (setcdr args (cons m (delq m args))))))
525 ;; bracket in the end range
526 ;; => "[]...-]"
527 ((setq m (rassq ?\] args))
528 ;; set ] at the beginning
529 (setq args (cons ?\] (rx-any-delete-from-range ?\] args)))
530 ;; set - at the end
531 (if (or (memq ?- args) (assq ?- args))
532 (setq args (nconc (rx-any-delete-from-range ?- args)
533 (list ?-)))))
534 ;; {no close bracket appears}
535 ;;
536 ;; bring single bar to the beginning
537 ((memq ?- args)
538 (setq args (cons ?- (delq ?- args))))
539 ;; bar start a range, bring it to the beginning
540 ((setq m (assq ?- args))
541 (setq args (cons m (delq m args))))
542 ;;
543 ;; hat at the beginning?
544 ((or (eq (car args) ?^) (eq (car-safe (car args)) ?^))
545 (setq args (if (cdr args)
546 `(,(cadr args) ,(car args) ,@(cddr args))
547 (nconc (rx-any-delete-from-range ?^ args)
548 (list ?^))))))
549 ;; some 1-char?
550 (if (and (null (cdr args)) (numberp (car args))
551 (or (= 1 (length
552 (setq s (regexp-quote (string (car args))))))
553 (and (equal (car args) ?^) ;; unnecessary predicate?
554 (null (eq rx-parent '!)))))
556 (concat "["
557 (mapconcat
558 (lambda (e) (cond
559 ((numberp e) (string e))
560 ((consp e)
561 (if (and (= (1+ (car e)) (cdr e))
562 ;; rx-any-condense-range should
563 ;; prevent this case from happening.
564 (null (memq (car e) '(?\] ?-)))
565 (null (memq (cdr e) '(?\] ?-))))
566 (string (car e) (cdr e))
567 (string (car e) ?- (cdr e))))
568 (e)))
569 args
570 nil)
571 "]"))))
574 (defun rx-check-not (arg)
575 "Check arg ARG for Rx `not'."
576 (unless (or (and (symbolp arg)
577 (string-match "\\`\\[\\[:[-a-z]+:\\]\\]\\'"
578 (condition-case nil
579 (rx-form arg)
580 (error ""))))
581 (eq arg 'word-boundary)
582 (and (consp arg)
583 (memq (car arg) '(not any in syntax category))))
584 (error "rx `not' syntax error: %s" arg))
585 t)
588 (defun rx-not (form)
589 "Parse and produce code from FORM. FORM is `(not ...)'."
590 (rx-check form)
591 (let ((result (rx-form (cadr form) '!))
592 case-fold-search)
593 (cond ((string-match "\\`\\[^" result)
594 (cond
595 ((equal result "[^]") "[^^]")
596 ((and (= (length result) 4) (null (eq rx-parent '!)))
597 (regexp-quote (substring result 2 3)))
598 ((concat "[" (substring result 2)))))
599 ((eq ?\[ (aref result 0))
600 (concat "[^" (substring result 1)))
601 ((string-match "\\`\\\\[scbw]" result)
602 (concat (upcase (substring result 0 2))
603 (substring result 2)))
604 ((string-match "\\`\\\\[SCBW]" result)
605 (concat (downcase (substring result 0 2))
606 (substring result 2)))
607 (t
608 (concat "[^" result "]")))))
611 (defun rx-not-char (form)
612 "Parse and produce code from FORM. FORM is `(not-char ...)'."
613 (rx-check form)
614 (rx-not `(not (in ,@(cdr form)))))
617 (defun rx-not-syntax (form)
618 "Parse and produce code from FORM. FORM is `(not-syntax SYNTAX)'."
619 (rx-check form)
620 (rx-not `(not (syntax ,@(cdr form)))))
623 (defun rx-trans-forms (form &optional skip)
624 "If FORM's length is greater than two, transform it to length two.
625 A form (HEAD REST ...) becomes (HEAD (and REST ...)).
626 If SKIP is non-nil, allow that number of items after the head, i.e.
627 `(= N REST ...)' becomes `(= N (and REST ...))' if SKIP is 1."
628 (unless skip (setq skip 0))
629 (let ((tail (nthcdr (1+ skip) form)))
630 (if (= (length tail) 1)
631 form
632 (let ((form (copy-sequence form)))
633 (setcdr (nthcdr skip form) (list (cons 'and tail)))
634 form))))
637 (defun rx-= (form)
638 "Parse and produce code from FORM `(= N ...)'."
639 (rx-check form)
640 (setq form (rx-trans-forms form 1))
641 (unless (and (integerp (nth 1 form))
642 (> (nth 1 form) 0))
643 (error "rx `=' requires positive integer first arg"))
644 (format "%s\\{%d\\}" (rx-form (nth 2 form) '*) (nth 1 form)))
647 (defun rx->= (form)
648 "Parse and produce code from FORM `(>= N ...)'."
649 (rx-check form)
650 (setq form (rx-trans-forms form 1))
651 (unless (and (integerp (nth 1 form))
652 (> (nth 1 form) 0))
653 (error "rx `>=' requires positive integer first arg"))
654 (format "%s\\{%d,\\}" (rx-form (nth 2 form) '*) (nth 1 form)))
657 (defun rx-** (form)
658 "Parse and produce code from FORM `(** N M ...)'."
659 (rx-check form)
660 (rx-form (cons 'repeat (cdr (rx-trans-forms form 2))) '*))
663 (defun rx-repeat (form)
664 "Parse and produce code from FORM.
665 FORM is either `(repeat N FORM1)' or `(repeat N M FORMS...)'."
666 (rx-check form)
667 (if (> (length form) 4)
668 (setq form (rx-trans-forms form 2)))
669 (if (null (nth 2 form))
670 (setq form (cons (nth 0 form) (cons (nth 1 form) (nthcdr 3 form)))))
671 (cond ((= (length form) 3)
672 (unless (and (integerp (nth 1 form))
673 (> (nth 1 form) 0))
674 (error "rx `repeat' requires positive integer first arg"))
675 (format "%s\\{%d\\}" (rx-form (nth 2 form) '*) (nth 1 form)))
676 ((or (not (integerp (nth 2 form)))
677 (< (nth 2 form) 0)
678 (not (integerp (nth 1 form)))
679 (< (nth 1 form) 0)
680 (< (nth 2 form) (nth 1 form)))
681 (error "rx `repeat' range error"))
682 (t
683 (format "%s\\{%d,%d\\}" (rx-form (nth 3 form) '*)
684 (nth 1 form) (nth 2 form)))))
687 (defun rx-submatch (form)
688 "Parse and produce code from FORM, which is `(submatch ...)'."
689 (concat "\\("
690 (if (= 2 (length form))
691 ;; Only one sub-form.
692 (rx-form (cadr form))
693 ;; Several sub-forms implicitly concatenated.
694 (mapconcat (lambda (re) (rx-form re ':)) (cdr form) nil))
695 "\\)"))
697 (defun rx-submatch-n (form)
698 "Parse and produce code from FORM, which is `(submatch-n N ...)'."
699 (let ((n (nth 1 form)))
700 (concat "\\(?" (number-to-string n) ":"
701 (if (= 3 (length form))
702 ;; Only one sub-form.
703 (rx-form (nth 2 form))
704 ;; Several sub-forms implicitly concatenated.
705 (mapconcat (lambda (re) (rx-form re ':)) (cddr form) nil))
706 "\\)")))
708 (defun rx-backref (form)
709 "Parse and produce code from FORM, which is `(backref N)'."
710 (rx-check form)
711 (format "\\%d" (nth 1 form)))
713 (defun rx-check-backref (arg)
714 "Check arg ARG for Rx `backref'."
715 (or (and (integerp arg) (>= arg 1) (<= arg 9))
716 (error "rx `backref' requires numeric 1<=arg<=9: %s" arg)))
718 (defun rx-kleene (form)
719 "Parse and produce code from FORM.
720 FORM is `(OP FORM1)', where OP is one of the `zero-or-one',
721 `zero-or-more' etc. operators.
722 If OP is one of `*', `+', `?', produce a greedy regexp.
723 If OP is one of `*?', `+?', `??', produce a non-greedy regexp.
724 If OP is anything else, produce a greedy regexp if `rx-greedy-flag'
725 is non-nil."
726 (rx-check form)
727 (setq form (rx-trans-forms form))
728 (let ((suffix (cond ((memq (car form) '(* + ?\s)) "")
729 ((memq (car form) '(*? +? ??)) "?")
730 (rx-greedy-flag "")
731 (t "?")))
732 (op (cond ((memq (car form) '(* *? 0+ zero-or-more)) "*")
733 ((memq (car form) '(+ +? 1+ one-or-more)) "+")
734 (t "?"))))
735 (rx-group-if
736 (concat (rx-form (cadr form) '*) op suffix)
737 (and (memq rx-parent '(t *)) rx-parent))))
740 (defun rx-atomic-p (r &optional lax)
741 "Return non-nil if regexp string R is atomic.
742 An atomic regexp R is one such that a suffix operator
743 appended to R will apply to all of R. For example, \"a\"
744 \"[abc]\" and \"\\(ab\\|ab*c\\)\" are atomic and \"ab\",
745 \"[ab]c\", and \"ab\\|ab*c\" are not atomic.
747 This function may return false negatives, but it will not
748 return false positives. It is nevertheless useful in
749 situations where an efficiency shortcut can be taken only if a
750 regexp is atomic. The function can be improved to detect
751 more cases of atomic regexps. Presently, this function
752 detects the following categories of atomic regexp;
754 a group or shy group: \\(...\\)
755 a character class: [...]
756 a single character: a
758 On the other hand, false negatives will be returned for
759 regexps that are atomic but end in operators, such as
760 \"a+\". I think these are rare. Probably such cases could
761 be detected without much effort. A guarantee of no false
762 negatives would require a theoretic specification of the set
763 of all atomic regexps."
764 (let ((l (length r)))
765 (cond
766 ((<= l 1))
767 ((= l 2) (= (aref r 0) ?\\))
768 ((= l 3) (string-match "\\`\\(?:\\\\[cCsS_]\\|\\[[^^]\\]\\)" r))
769 ((null lax)
770 (cond
771 ((string-match "\\`\\[^?\]?\\(?:\\[:[a-z]+:]\\|[^\]]\\)*\\]\\'" r))
772 ((string-match "\\`\\\\(\\(?:[^\\]\\|\\\\[^\)]\\)*\\\\)\\'" r)))))))
775 (defun rx-syntax (form)
776 "Parse and produce code from FORM, which is `(syntax SYMBOL)'."
777 (rx-check form)
778 (let* ((sym (cadr form))
779 (syntax (cdr (assq sym rx-syntax))))
780 (unless syntax
781 ;; Try sregex compatibility.
782 (cond
783 ((characterp sym) (setq syntax sym))
784 ((symbolp sym)
785 (let ((name (symbol-name sym)))
786 (if (= 1 (length name))
787 (setq syntax (aref name 0))))))
788 (unless syntax
789 (error "Unknown rx syntax `%s'" sym)))
790 (format "\\s%c" syntax)))
793 (defun rx-check-category (form)
794 "Check the argument FORM of a `(category FORM)'."
795 (unless (or (integerp form)
796 (cdr (assq form rx-categories)))
797 (error "Unknown category `%s'" form))
798 t)
801 (defun rx-category (form)
802 "Parse and produce code from FORM, which is `(category SYMBOL)'."
803 (rx-check form)
804 (let ((char (if (integerp (cadr form))
805 (cadr form)
806 (cdr (assq (cadr form) rx-categories)))))
807 (format "\\c%c" char)))
810 (defun rx-eval (form)
811 "Parse and produce code from FORM, which is `(eval FORM)'."
812 (rx-check form)
813 (rx-form (eval (cadr form)) rx-parent))
816 (defun rx-greedy (form)
817 "Parse and produce code from FORM.
818 If FORM is '(minimal-match FORM1)', non-greedy versions of `*',
819 `+', and `?' operators will be used in FORM1. If FORM is
820 '(maximal-match FORM1)', greedy operators will be used."
821 (rx-check form)
822 (let ((rx-greedy-flag (eq (car form) 'maximal-match)))
823 (rx-form (cadr form) rx-parent)))
826 (defun rx-regexp (form)
827 "Parse and produce code from FORM, which is `(regexp STRING)'."
828 (rx-check form)
829 (rx-group-if (cadr form) rx-parent))
832 (defun rx-form (form &optional rx-parent)
833 "Parse and produce code for regular expression FORM.
834 FORM is a regular expression in sexp form.
835 RX-PARENT shows which type of expression calls and controls putting of
836 shy groups around the result and some more in other functions."
837 (cond
838 ((stringp form)
839 (rx-group-if (regexp-quote form)
840 (if (and (eq rx-parent '*) (< 1 (length form)))
841 rx-parent)))
842 ((integerp form)
843 (regexp-quote (char-to-string form)))
844 ((symbolp form)
845 (let ((info (rx-info form nil)))
846 (cond ((stringp info)
847 info)
848 ((null info)
849 (error "Unknown rx form `%s'" form))
850 (t
851 (funcall (nth 0 info) form)))))
852 ((consp form)
853 (let ((info (rx-info (car form) 'head)))
854 (unless (consp info)
855 (error "Unknown rx form `%s'" (car form)))
856 (funcall (nth 0 info) form)))
857 (t
858 (error "rx syntax error at `%s'" form))))
861 ;;;###autoload
862 (defun rx-to-string (form &optional no-group)
863 "Parse and produce code for regular expression FORM.
864 FORM is a regular expression in sexp form.
865 NO-GROUP non-nil means don't put shy groups around the result."
866 (rx-group-if (rx-form form) (null no-group)))
869 ;;;###autoload
870 (defmacro rx (&rest regexps)
871 "Translate regular expressions REGEXPS in sexp form to a regexp string.
872 REGEXPS is a non-empty sequence of forms of the sort listed below.
874 Note that `rx' is a Lisp macro; when used in a Lisp program being
875 compiled, the translation is performed by the compiler.
876 See `rx-to-string' for how to do such a translation at run-time.
878 The following are valid subforms of regular expressions in sexp
879 notation.
881 STRING
882 matches string STRING literally.
884 CHAR
885 matches character CHAR literally.
887 `not-newline', `nonl'
888 matches any character except a newline.
890 `anything'
891 matches any character
893 `(any SET ...)'
894 `(in SET ...)'
895 `(char SET ...)'
896 matches any character in SET .... SET may be a character or string.
897 Ranges of characters can be specified as `A-Z' in strings.
898 Ranges may also be specified as conses like `(?A . ?Z)'.
900 SET may also be the name of a character class: `digit',
901 `control', `hex-digit', `blank', `graph', `print', `alnum',
902 `alpha', `ascii', `nonascii', `lower', `punct', `space', `upper',
903 `word', or one of their synonyms.
905 `(not (any SET ...))'
906 matches any character not in SET ...
908 `line-start', `bol'
909 matches the empty string, but only at the beginning of a line
910 in the text being matched
912 `line-end', `eol'
913 is similar to `line-start' but matches only at the end of a line
915 `string-start', `bos', `bot'
916 matches the empty string, but only at the beginning of the
917 string being matched against.
919 `string-end', `eos', `eot'
920 matches the empty string, but only at the end of the
921 string being matched against.
923 `buffer-start'
924 matches the empty string, but only at the beginning of the
925 buffer being matched against. Actually equivalent to `string-start'.
927 `buffer-end'
928 matches the empty string, but only at the end of the
929 buffer being matched against. Actually equivalent to `string-end'.
931 `point'
932 matches the empty string, but only at point.
934 `word-start', `bow'
935 matches the empty string, but only at the beginning of a word.
937 `word-end', `eow'
938 matches the empty string, but only at the end of a word.
940 `word-boundary'
941 matches the empty string, but only at the beginning or end of a
942 word.
944 `(not word-boundary)'
945 `not-word-boundary'
946 matches the empty string, but not at the beginning or end of a
947 word.
949 `symbol-start'
950 matches the empty string, but only at the beginning of a symbol.
952 `symbol-end'
953 matches the empty string, but only at the end of a symbol.
955 `digit', `numeric', `num'
956 matches 0 through 9.
958 `control', `cntrl'
959 matches ASCII control characters.
961 `hex-digit', `hex', `xdigit'
962 matches 0 through 9, a through f and A through F.
964 `blank'
965 matches space and tab only.
967 `graphic', `graph'
968 matches graphic characters--everything except whitespace, ASCII
969 and non-ASCII control characters, surrogates, and codepoints
970 unassigned by Unicode.
972 `printing', `print'
973 matches whitespace and graphic characters.
975 `alphanumeric', `alnum'
976 matches alphabetic characters and digits. (For multibyte characters,
977 it matches according to Unicode character properties.)
979 `letter', `alphabetic', `alpha'
980 matches alphabetic characters. (For multibyte characters,
981 it matches according to Unicode character properties.)
983 `ascii'
984 matches ASCII (unibyte) characters.
986 `nonascii'
987 matches non-ASCII (multibyte) characters.
989 `lower', `lower-case'
990 matches anything lower-case.
992 `upper', `upper-case'
993 matches anything upper-case.
995 `punctuation', `punct'
996 matches punctuation. (But at present, for multibyte characters,
997 it matches anything that has non-word syntax.)
999 `space', `whitespace', `white'
1000 matches anything that has whitespace syntax.
1002 `word', `wordchar'
1003 matches anything that has word syntax.
1005 `not-wordchar'
1006 matches anything that has non-word syntax.
1008 `(syntax SYNTAX)'
1009 matches a character with syntax SYNTAX. SYNTAX must be one
1010 of the following symbols, or a symbol corresponding to the syntax
1011 character, e.g. `\\.' for `\\s.'.
1013 `whitespace' (\\s- in string notation)
1014 `punctuation' (\\s.)
1015 `word' (\\sw)
1016 `symbol' (\\s_)
1017 `open-parenthesis' (\\s()
1018 `close-parenthesis' (\\s))
1019 `expression-prefix' (\\s')
1020 `string-quote' (\\s\")
1021 `paired-delimiter' (\\s$)
1022 `escape' (\\s\\)
1023 `character-quote' (\\s/)
1024 `comment-start' (\\s<)
1025 `comment-end' (\\s>)
1026 `string-delimiter' (\\s|)
1027 `comment-delimiter' (\\s!)
1029 `(not (syntax SYNTAX))'
1030 matches a character that doesn't have syntax SYNTAX.
1032 `(category CATEGORY)'
1033 matches a character with category CATEGORY. CATEGORY must be
1034 either a character to use for C, or one of the following symbols.
1036 `consonant' (\\c0 in string notation)
1037 `base-vowel' (\\c1)
1038 `upper-diacritical-mark' (\\c2)
1039 `lower-diacritical-mark' (\\c3)
1040 `tone-mark' (\\c4)
1041 `symbol' (\\c5)
1042 `digit' (\\c6)
1043 `vowel-modifying-diacritical-mark' (\\c7)
1044 `vowel-sign' (\\c8)
1045 `semivowel-lower' (\\c9)
1046 `not-at-end-of-line' (\\c<)
1047 `not-at-beginning-of-line' (\\c>)
1048 `alpha-numeric-two-byte' (\\cA)
1049 `chinese-two-byte' (\\cC)
1050 `greek-two-byte' (\\cG)
1051 `japanese-hiragana-two-byte' (\\cH)
1052 `indian-tow-byte' (\\cI)
1053 `japanese-katakana-two-byte' (\\cK)
1054 `korean-hangul-two-byte' (\\cN)
1055 `cyrillic-two-byte' (\\cY)
1056 `combining-diacritic' (\\c^)
1057 `ascii' (\\ca)
1058 `arabic' (\\cb)
1059 `chinese' (\\cc)
1060 `ethiopic' (\\ce)
1061 `greek' (\\cg)
1062 `korean' (\\ch)
1063 `indian' (\\ci)
1064 `japanese' (\\cj)
1065 `japanese-katakana' (\\ck)
1066 `latin' (\\cl)
1067 `lao' (\\co)
1068 `tibetan' (\\cq)
1069 `japanese-roman' (\\cr)
1070 `thai' (\\ct)
1071 `vietnamese' (\\cv)
1072 `hebrew' (\\cw)
1073 `cyrillic' (\\cy)
1074 `can-break' (\\c|)
1076 `(not (category CATEGORY))'
1077 matches a character that doesn't have category CATEGORY.
1079 `(and SEXP1 SEXP2 ...)'
1080 `(: SEXP1 SEXP2 ...)'
1081 `(seq SEXP1 SEXP2 ...)'
1082 `(sequence SEXP1 SEXP2 ...)'
1083 matches what SEXP1 matches, followed by what SEXP2 matches, etc.
1085 `(submatch SEXP1 SEXP2 ...)'
1086 `(group SEXP1 SEXP2 ...)'
1087 like `and', but makes the match accessible with `match-end',
1088 `match-beginning', and `match-string'.
1090 `(submatch-n N SEXP1 SEXP2 ...)'
1091 `(group-n N SEXP1 SEXP2 ...)'
1092 like `group', but make it an explicitly-numbered group with
1093 group number N.
1095 `(or SEXP1 SEXP2 ...)'
1096 `(| SEXP1 SEXP2 ...)'
1097 matches anything that matches SEXP1 or SEXP2, etc. If all
1098 args are strings, use `regexp-opt' to optimize the resulting
1099 regular expression.
1101 `(minimal-match SEXP)'
1102 produce a non-greedy regexp for SEXP. Normally, regexps matching
1103 zero or more occurrences of something are \"greedy\" in that they
1104 match as much as they can, as long as the overall regexp can
1105 still match. A non-greedy regexp matches as little as possible.
1107 `(maximal-match SEXP)'
1108 produce a greedy regexp for SEXP. This is the default.
1110 Below, `SEXP ...' represents a sequence of regexp forms, treated as if
1111 enclosed in `(and ...)'.
1113 `(zero-or-more SEXP ...)'
1114 `(0+ SEXP ...)'
1115 matches zero or more occurrences of what SEXP ... matches.
1117 `(* SEXP ...)'
1118 like `zero-or-more', but always produces a greedy regexp, independent
1119 of `rx-greedy-flag'.
1121 `(*? SEXP ...)'
1122 like `zero-or-more', but always produces a non-greedy regexp,
1123 independent of `rx-greedy-flag'.
1125 `(one-or-more SEXP ...)'
1126 `(1+ SEXP ...)'
1127 matches one or more occurrences of SEXP ...
1129 `(+ SEXP ...)'
1130 like `one-or-more', but always produces a greedy regexp.
1132 `(+? SEXP ...)'
1133 like `one-or-more', but always produces a non-greedy regexp.
1135 `(zero-or-one SEXP ...)'
1136 `(optional SEXP ...)'
1137 `(opt SEXP ...)'
1138 matches zero or one occurrences of A.
1140 `(? SEXP ...)'
1141 like `zero-or-one', but always produces a greedy regexp.
1143 `(?? SEXP ...)'
1144 like `zero-or-one', but always produces a non-greedy regexp.
1146 `(repeat N SEXP)'
1147 `(= N SEXP ...)'
1148 matches N occurrences.
1150 `(>= N SEXP ...)'
1151 matches N or more occurrences.
1153 `(repeat N M SEXP)'
1154 `(** N M SEXP ...)'
1155 matches N to M occurrences.
1157 `(backref N)'
1158 matches what was matched previously by submatch N.
1160 `(eval FORM)'
1161 evaluate FORM and insert result. If result is a string,
1162 `regexp-quote' it.
1164 `(regexp REGEXP)'
1165 include REGEXP in string notation in the result."
1166 (cond ((null regexps)
1167 (error "No regexp"))
1168 ((cdr regexps)
1169 (rx-to-string `(and ,@regexps) t))
1170 (t
1171 (rx-to-string (car regexps) t))))
1172 \f
1173 ;; ;; sregex.el replacement
1175 ;; ;;;###autoload (provide 'sregex)
1176 ;; ;;;###autoload (autoload 'sregex "rx")
1177 ;; (defalias 'sregex 'rx-to-string)
1178 ;; ;;;###autoload (autoload 'sregexq "rx" nil nil 'macro)
1179 ;; (defalias 'sregexq 'rx)
1180 \f
1181 (provide 'rx)
1183 ;;; rx.el ends here