lisp/emacs-lisp/re-builder.el

   1 ;;; re-builder.el --- building Regexps with visual feedback -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 1999-2013 Free Software Foundation, Inc.
   4
   5 ;; Author: Detlev Zundel <dzu@gnu.org>
   6 ;; Keywords: matching, lisp, tools
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; When I have to come up with regular expressions that are more
  26 ;; complex than simple string matchers, especially if they contain sub
  27 ;; expressions, I find myself spending quite some time in the
  28 ;; `development cycle'.  `re-builder' aims to shorten this time span
  29 ;; so I can get on with the more interesting bits.
  30
  31 ;; With it you can have immediate visual feedback about how well the
  32 ;; regexp behaves to your expectations on the intended data.
  33
  34 ;; When called up `re-builder' attaches itself to the current buffer
  35 ;; which becomes its target buffer, where all the matching is done.
  36 ;; The active window is split so you have a view on the data while
  37 ;; authoring the RE.  If the edited expression is valid the matches in
  38 ;; the target buffer are marked automatically with colored overlays
  39 ;; (for non-color displays see below) giving you feedback over the
  40 ;; extents of the matched (sub) expressions.  The (non-)validity is
  41 ;; shown only in the mode line without throwing the errors at you.  If
  42 ;; you want to know the reason why RE Builder considers it as invalid
  43 ;; call `reb-force-update' ("\C-c\C-u") which should reveal the error.
  44
  45 ;; The target buffer can be changed with `reb-change-target-buffer'
  46 ;; ("\C-c\C-b").  Changing the target buffer automatically removes
  47 ;; the overlays from the old buffer and displays the new one in the
  48 ;; target window.
  49
  50 ;; The `re-builder' keeps the focus while updating the matches in the
  51 ;; target buffer so corrections are easy to incorporate.  If you are
  52 ;; satisfied with the result you can paste the RE to the kill-ring
  53 ;; with `reb-copy' ("\C-c\C-w"), quit the `re-builder' ("\C-c\C-q")
  54 ;; and use it wherever you need it.
  55
  56 ;; As the automatic updates can take some time on large buffers, they
  57 ;; can be limited by `reb-auto-match-limit' so that they should not
  58 ;; have a negative impact on the editing.  Setting it to nil makes
  59 ;; even the auto updates go all the way.  Forcing an update overrides
  60 ;; this limit allowing an easy way to see all matches.
  61
  62 ;; Currently `re-builder' understands three different forms of input,
  63 ;; namely `read', `string', and `rx' syntax.  Read
  64 ;; syntax and string syntax are both delimited by `"'s and behave
  65 ;; according to their name.  With the `string' syntax there's no need
  66 ;; to escape the backslashes and double quotes simplifying the editing
  67 ;; somewhat.  The other three allow editing of symbolic regular
  68 ;; expressions supported by the packages of the same name.
  69
  70 ;; Editing symbolic expressions is done through a major mode derived
  71 ;; from `emacs-lisp-mode' so you'll get all the good stuff like
  72 ;; automatic indentation and font-locking etc.
  73
  74 ;; When editing a symbolic regular expression, only the first
  75 ;; expression in the RE Builder buffer is considered, which helps
  76 ;; limiting the extent of the expression like the `"'s do for the text
  77 ;; modes.  For the `rx' syntax the function `rx-to-string' is applied to
  78 ;; the evaluated expression read.  So you can use quoted arguments
  79 ;; with something like '("findme") or you can construct arguments to
  80 ;; your hearts delight with a valid ELisp expression.  (The compiled
  81 ;; string form will be copied by `reb-copy')  If you want to take
  82 ;; a glance at the corresponding string you can temporarily change the
  83 ;; input syntax.
  84
  85 ;; Changing the input syntax is transparent (for the obvious exception
  86 ;; non-symbolic -> symbolic) so you can change your mind as often as
  87 ;; you like.
  88
  89 ;; There is also a shortcut function for toggling the
  90 ;; `case-fold-search' variable in the target buffer with an immediate
  91 ;; update.
  92
  93
  94 ;; Q: But what if my display cannot show colored overlays?
  95 ;; A: Then the cursor will flash around the matched text making it stand
  96 ;;    out.
  97
  98 ;; Q: But how can I then make out the sub-expressions?
  99 ;; A: Thats where the `sub-expression mode' comes in.  In it only the
 100 ;;    digit keys are assigned to perform an update that will flash the
 101 ;;    corresponding subexp only.
 102
 103
 104 ;;; Code:
 105
 106 ;; On XEmacs, load the overlay compatibility library
 107 (unless (fboundp 'make-overlay)
 108   (require 'overlay))
 109
 110 ;; User customizable variables
 111 (defgroup re-builder nil
 112   "Options for the RE Builder."
 113   :group 'lisp
 114   :prefix "reb-")
 115
 116 (defcustom reb-blink-delay 0.5
 117   "Seconds to blink cursor for next/previous match in RE Builder."
 118   :group 're-builder
 119   :type 'number)
 120
 121 (defcustom reb-mode-hook nil
 122   "Hooks to run on entering RE Builder mode."
 123   :group 're-builder
 124   :type 'hook)
 125
 126 (defcustom reb-re-syntax 'read
 127   "Syntax for the REs in the RE Builder.
 128 Can either be `read', `string', or `rx'."
 129   :group 're-builder
 130   :type '(choice (const :tag "Read syntax" read)
 131                  (const :tag "String syntax" string)
 132                  (const :tag "`rx' syntax" rx)))
 133
 134 (defcustom reb-auto-match-limit 200
 135   "Positive integer limiting the matches for RE Builder auto updates.
 136 Set it to nil if you don't want limits here."
 137   :group 're-builder
 138   :type '(restricted-sexp :match-alternatives
 139                           (integerp 'nil)))
 140
 141
 142 (defface reb-match-0
 143   '((((class color) (background light))
 144      :background "lightblue")
 145     (((class color) (background dark))
 146      :background "steelblue4")
 147     (t
 148      :inverse-video t))
 149   "Used for displaying the whole match."
 150   :group 're-builder)
 151
 152 (defface reb-match-1
 153   '((((class color) (background light))
 154      :background "aquamarine")
 155     (((class color) (background dark))
 156      :background "blue3")
 157     (t
 158      :inverse-video t))
 159   "Used for displaying the first matching subexpression."
 160   :group 're-builder)
 161
 162 (defface reb-match-2
 163   '((((class color) (background light))
 164      :background "springgreen")
 165     (((class color) (background dark))
 166      :background "chartreuse4")
 167     (t
 168      :inverse-video t))
 169   "Used for displaying the second matching subexpression."
 170   :group 're-builder)
 171
 172 (defface reb-match-3
 173   '((((min-colors 88) (class color) (background light))
 174      :background "yellow1")
 175     (((class color) (background light))
 176      :background "yellow")
 177     (((class color) (background dark))
 178      :background "sienna4")
 179     (t
 180      :inverse-video t))
 181   "Used for displaying the third matching subexpression."
 182   :group 're-builder)
 183
 184 ;; Internal variables below
 185 (defvar reb-mode nil
 186   "Enables the RE Builder minor mode.")
 187
 188 (defvar reb-target-buffer nil
 189   "Buffer to which the RE is applied to.")
 190
 191 (defvar reb-target-window nil
 192   "Window to which the RE is applied to.")
 193
 194 (defvar reb-regexp nil
 195   "Last regexp used by RE Builder.")
 196
 197 (defvar reb-regexp-src nil
 198   "Last regexp used by RE Builder before processing it.
 199 Except for Lisp syntax this is the same as `reb-regexp'.")
 200
 201 (defvar reb-overlays nil
 202   "List of overlays of the RE Builder.")
 203
 204 (defvar reb-window-config nil
 205   "Old window configuration.")
 206
 207 (defvar reb-subexp-mode nil
 208   "Indicates whether sub-exp mode is active.")
 209
 210 (defvar reb-subexp-displayed nil
 211   "Indicates which sub-exp is active.")
 212
 213 (defvar reb-mode-string ""
 214   "String in mode line for additional info.")
 215
 216 (defvar reb-valid-string ""
 217   "String in mode line showing validity of RE.")
 218
 219 (make-variable-buffer-local 'reb-overlays)
 220 (make-variable-buffer-local 'reb-regexp)
 221 (make-variable-buffer-local 'reb-regexp-src)
 222
 223 (defconst reb-buffer "*RE-Builder*"
 224   "Buffer to use for the RE Builder.")
 225
 226 ;; Define the local "\C-c" keymap
 227 (defvar reb-mode-map
 228   (let ((map (make-sparse-keymap))
 229         (menu-map (make-sparse-keymap)))
 230     (define-key map "\C-c\C-c" 'reb-toggle-case)
 231     (define-key map "\C-c\C-q" 'reb-quit)
 232     (define-key map "\C-c\C-w" 'reb-copy)
 233     (define-key map "\C-c\C-s" 'reb-next-match)
 234     (define-key map "\C-c\C-r" 'reb-prev-match)
 235     (define-key map "\C-c\C-i" 'reb-change-syntax)
 236     (define-key map "\C-c\C-e" 'reb-enter-subexp-mode)
 237     (define-key map "\C-c\C-b" 'reb-change-target-buffer)
 238     (define-key map "\C-c\C-u" 'reb-force-update)
 239     (define-key map [menu-bar reb-mode] (cons "Re-Builder" menu-map))
 240     (define-key menu-map [rq]
 241       '(menu-item "Quit" reb-quit
 242                   :help "Quit the RE Builder mode"))
 243     (define-key menu-map [rt]
 244       '(menu-item "Case sensitive" reb-toggle-case
 245                   :button (:toggle . (with-current-buffer
 246                                          reb-target-buffer
 247                                        (null case-fold-search)))
 248                   :help "Toggle case sensitivity of searches for RE Builder target buffer"))
 249     (define-key menu-map [rb]
 250       '(menu-item "Change target buffer..." reb-change-target-buffer
 251                   :help "Change the target buffer and display it in the target window"))
 252     (define-key menu-map [rs]
 253       '(menu-item "Change syntax..." reb-change-syntax
 254                   :help "Change the syntax used by the RE Builder"))
 255     (define-key menu-map [re]
 256       '(menu-item "Enter subexpression mode" reb-enter-subexp-mode
 257                   :help "Enter the subexpression mode in the RE Builder"))
 258     (define-key menu-map [ru]
 259       '(menu-item "Force update" reb-force-update
 260                   :help "Force an update in the RE Builder target window without a match limit"))
 261     (define-key menu-map [rn]
 262       '(menu-item "Go to next match" reb-next-match
 263                   :help "Go to next match in the RE Builder target window"))
 264     (define-key menu-map [rp]
 265       '(menu-item "Go to previous match" reb-prev-match
 266                   :help "Go to previous match in the RE Builder target window"))
 267     (define-key menu-map [rc]
 268       '(menu-item "Copy current RE" reb-copy
 269                   :help "Copy current RE into the kill ring for later insertion"))
 270     map)
 271   "Keymap used by the RE Builder.")
 272
 273 (define-derived-mode reb-mode nil "RE Builder"
 274   "Major mode for interactively building Regular Expressions."
 275   (set (make-local-variable 'blink-matching-paren) nil)
 276   (reb-mode-common))
 277
 278 (defvar reb-lisp-mode-map
 279   (let ((map (make-sparse-keymap)))
 280     ;; Use the same "\C-c" keymap as `reb-mode' and use font-locking from
 281     ;; `emacs-lisp-mode'
 282     (define-key map "\C-c" (lookup-key reb-mode-map "\C-c"))
 283     map))
 284
 285 (define-derived-mode reb-lisp-mode
 286   emacs-lisp-mode "RE Builder Lisp"
 287   "Major mode for interactively building symbolic Regular Expressions."
 288   ;; Pull in packages as needed
 289   (cond ((memq reb-re-syntax '(sregex rx)) ; rx-to-string is autoloaded
 290          (require 'rx)))                   ; require rx anyway
 291   (reb-mode-common))
 292
 293 (defvar reb-subexp-mode-map
 294   (let ((m (make-keymap)))
 295     (suppress-keymap m)
 296     ;; Again share the "\C-c" keymap for the commands
 297     (define-key m "\C-c" (lookup-key reb-mode-map "\C-c"))
 298     (define-key m "q" 'reb-quit-subexp-mode)
 299     (dotimes (digit 10)
 300       (define-key m (int-to-string digit) 'reb-display-subexp))
 301     m)
 302   "Keymap used by the RE Builder for the subexpression mode.")
 303
 304 (defun reb-mode-common ()
 305   "Setup functions common to functions `reb-mode' and `reb-mode-lisp'."
 306
 307   (setq reb-mode-string  ""
 308         reb-valid-string ""
 309         mode-line-buffer-identification
 310                          '(25 . ("%b" reb-mode-string reb-valid-string)))
 311   (reb-update-modestring)
 312   (add-hook 'after-change-functions 'reb-auto-update nil t)
 313   ;; At least make the overlays go away if the buffer is killed
 314   (add-hook 'kill-buffer-hook 'reb-kill-buffer nil t)
 315   (reb-auto-update nil nil nil))
 316
 317 (defun reb-color-display-p ()
 318   "Return t if display is capable of displaying colors."
 319   (eq 'color
 320       ;; emacs/xemacs compatibility
 321       (if (fboundp 'frame-parameter)
 322           (frame-parameter nil 'display-type)
 323         (if (fboundp 'frame-property)
 324             (frame-property (selected-frame) 'display-type)))))
 325
 326 (defsubst reb-lisp-syntax-p ()
 327   "Return non-nil if RE Builder uses a Lisp syntax."
 328   (memq reb-re-syntax '(sregex rx)))
 329
 330 (defmacro reb-target-binding (symbol)
 331   "Return binding for SYMBOL in the RE Builder target buffer."
 332   `(with-current-buffer reb-target-buffer ,symbol))
 333
 334 (defun reb-initialize-buffer ()
 335   "Initialize the current buffer as a RE Builder buffer."
 336   (erase-buffer)
 337   (reb-insert-regexp)
 338   (goto-char (+ 2 (point-min)))
 339   (cond ((reb-lisp-syntax-p)
 340          (reb-lisp-mode))
 341         (t (reb-mode)))
 342   (reb-do-update))
 343
 344 (defun reb-mode-buffer-p ()
 345   "Return non-nil if the current buffer is a RE Builder buffer."
 346   (memq major-mode '(reb-mode reb-lisp-mode)))
 347
 348 ;;; This is to help people find this in Apropos.
 349 ;;;###autoload
 350 (defalias 'regexp-builder 're-builder)
 351
 352 ;;;###autoload
 353 (defun re-builder ()
 354   "Construct a regexp interactively.
 355 This command makes the current buffer the \"target\" buffer of
 356 the regexp builder.  It displays a buffer named \"*RE-Builder*\"
 357 in another window, initially containing an empty regexp.
 358
 359 As you edit the regexp in the \"*RE-Builder*\" buffer, the
 360 matching parts of the target buffer will be highlighted."
 361   (interactive)
 362   (if (and (string= (buffer-name) reb-buffer)
 363            (reb-mode-buffer-p))
 364       (message "Already in the RE Builder")
 365     (when reb-target-buffer
 366       (reb-delete-overlays))
 367     (setq reb-target-buffer (current-buffer)
 368           reb-target-window (selected-window))
 369     (select-window (or (get-buffer-window reb-buffer)
 370                        (progn
 371                          (setq reb-window-config (current-window-configuration))
 372                          (split-window (selected-window) (- (window-height) 4)))))
 373     (switch-to-buffer (get-buffer-create reb-buffer))
 374     (reb-initialize-buffer)))
 375
 376 (defun reb-change-target-buffer (buf)
 377   "Change the target buffer and display it in the target window."
 378   (interactive "bSet target buffer to: ")
 379
 380   (let ((buffer (get-buffer buf)))
 381     (if (not buffer)
 382         (error "No such buffer")
 383       (reb-delete-overlays)
 384       (setq reb-target-buffer buffer)
 385       (reb-do-update
 386        (if reb-subexp-mode reb-subexp-displayed nil))
 387       (reb-update-modestring))))
 388
 389 (defun reb-force-update ()
 390   "Force an update in the RE Builder target window without a match limit."
 391   (interactive)
 392
 393   (let ((reb-auto-match-limit nil))
 394     (reb-update-overlays
 395      (if reb-subexp-mode reb-subexp-displayed nil))))
 396
 397 (defun reb-quit ()
 398   "Quit the RE Builder mode."
 399   (interactive)
 400
 401   (setq reb-subexp-mode nil
 402         reb-subexp-displayed nil)
 403   (reb-delete-overlays)
 404   (bury-buffer)
 405   (set-window-configuration reb-window-config))
 406
 407 (defun reb-next-match ()
 408   "Go to next match in the RE Builder target window."
 409   (interactive)
 410
 411   (reb-assert-buffer-in-window)
 412   (with-selected-window reb-target-window
 413     (if (not (re-search-forward reb-regexp (point-max) t))
 414         (message "No more matches")
 415       (reb-show-subexp
 416        (or (and reb-subexp-mode reb-subexp-displayed) 0)
 417        t))))
 418
 419 (defun reb-prev-match ()
 420   "Go to previous match in the RE Builder target window."
 421   (interactive)
 422
 423   (reb-assert-buffer-in-window)
 424   (with-selected-window reb-target-window
 425     (let ((p (point)))
 426       (goto-char (1- p))
 427       (if (re-search-backward reb-regexp (point-min) t)
 428           (reb-show-subexp
 429            (or (and reb-subexp-mode reb-subexp-displayed) 0)
 430            t)
 431         (goto-char p)
 432         (message "No more matches")))))
 433
 434 (defun reb-toggle-case ()
 435   "Toggle case sensitivity of searches for RE Builder target buffer."
 436   (interactive)
 437
 438   (with-current-buffer reb-target-buffer
 439     (setq case-fold-search (not case-fold-search)))
 440   (reb-update-modestring)
 441   (reb-auto-update nil nil nil t))
 442
 443 (defun reb-copy ()
 444   "Copy current RE into the kill ring for later insertion."
 445   (interactive)
 446
 447   (reb-update-regexp)
 448   (let ((re (with-output-to-string
 449               (print (reb-target-binding reb-regexp)))))
 450     (kill-new (substring re 1 (1- (length re))))
 451     (message "Regexp copied to kill-ring")))
 452
 453 ;; The subexpression mode is not electric because the number of
 454 ;; matches should be seen rather than a prompt.
 455 (defun reb-enter-subexp-mode ()
 456   "Enter the subexpression mode in the RE Builder."
 457   (interactive)
 458   (setq reb-subexp-mode t)
 459   (reb-update-modestring)
 460   (use-local-map reb-subexp-mode-map)
 461   (message "`0'-`9' to display subexpressions  `q' to quit subexp mode"))
 462
 463 (defun reb-show-subexp (subexp &optional pause)
 464   "Visually show limit of subexpression SUBEXP of recent search.
 465 On color displays this just puts point to the end of the expression as
 466 the match should already be marked by an overlay.
 467 On other displays jump to the beginning and the end of it.
 468 If the optional PAUSE is non-nil then pause at the end in any case."
 469   (with-selected-window reb-target-window
 470     (unless (reb-color-display-p)
 471       (goto-char (match-beginning subexp))
 472       (sit-for reb-blink-delay))
 473     (goto-char (match-end subexp))
 474     (when (or (not (reb-color-display-p)) pause)
 475       (sit-for reb-blink-delay))))
 476
 477 (defun reb-quit-subexp-mode ()
 478   "Quit the subexpression mode in the RE Builder."
 479   (interactive)
 480   (setq reb-subexp-mode nil
 481         reb-subexp-displayed nil)
 482   (reb-update-modestring)
 483   (use-local-map reb-mode-map)
 484   (reb-do-update))
 485
 486 (defun reb-change-syntax (&optional syntax)
 487   "Change the syntax used by the RE Builder.
 488 Optional argument SYNTAX must be specified if called non-interactively."
 489   (interactive
 490    (list (intern
 491           (completing-read "Select syntax: "
 492                            (mapcar (lambda (el) (cons (symbol-name el) 1))
 493                                    '(read string sregex rx))
 494                            nil t (symbol-name reb-re-syntax)))))
 495
 496   (if (memq syntax '(read string sregex rx))
 497       (let ((buffer (get-buffer reb-buffer)))
 498         (setq reb-re-syntax syntax)
 499         (when buffer
 500           (with-current-buffer buffer
 501             (reb-initialize-buffer))))
 502     (error "Invalid syntax: %s" syntax)))
 503
 504
 505 ;; Non-interactive functions below
 506 (defun reb-do-update (&optional subexp)
 507   "Update matches in the RE Builder target window.
 508 If SUBEXP is non-nil mark only the corresponding sub-expressions."
 509
 510   (reb-assert-buffer-in-window)
 511   (reb-update-regexp)
 512   (reb-update-overlays subexp))
 513
 514 (defun reb-auto-update (_beg _end _lenold &optional force)
 515   "Called from `after-update-functions' to update the display.
 516 BEG, END and LENOLD are passed in from the hook.
 517 An actual update is only done if the regexp has changed or if the
 518 optional fourth argument FORCE is non-nil."
 519   (let ((prev-valid reb-valid-string)
 520         (new-valid
 521          (condition-case nil
 522              (progn
 523                (when (or (reb-update-regexp) force)
 524                  (reb-do-update))
 525                "")
 526            (error " *invalid*"))))
 527     (setq reb-valid-string new-valid)
 528     (force-mode-line-update)
 529
 530     ;; Through the caching of the re a change invalidating the syntax
 531     ;; for symbolic expressions will not delete the overlays so we
 532     ;; catch it here
 533     (when (and (reb-lisp-syntax-p)
 534                (not (string= prev-valid new-valid))
 535                (string= prev-valid ""))
 536       (reb-delete-overlays))))
 537
 538 (defun reb-delete-overlays ()
 539   "Delete all RE Builder overlays in the `reb-target-buffer' buffer."
 540   (when (buffer-live-p reb-target-buffer)
 541     (with-current-buffer reb-target-buffer
 542       (mapc 'delete-overlay reb-overlays)
 543       (setq reb-overlays nil))))
 544
 545 (defun reb-assert-buffer-in-window ()
 546   "Assert that `reb-target-buffer' is displayed in `reb-target-window'."
 547
 548   (if (not (eq reb-target-buffer (window-buffer reb-target-window)))
 549       (set-window-buffer reb-target-window reb-target-buffer)))
 550
 551 (defun reb-update-modestring ()
 552   "Update the variable `reb-mode-string' displayed in the mode line."
 553   (setq reb-mode-string
 554         (concat
 555          (if reb-subexp-mode
 556              (format " (subexp %s)" (or reb-subexp-displayed "-"))
 557            "")
 558          (if (not (reb-target-binding case-fold-search))
 559              " Case"
 560            "")))
 561   (force-mode-line-update))
 562
 563 (defun reb-display-subexp (&optional subexp)
 564   "Highlight only subexpression SUBEXP in the RE Builder."
 565   (interactive)
 566
 567   (setq reb-subexp-displayed
 568         (or subexp (string-to-number (format "%c" last-command-event))))
 569   (reb-update-modestring)
 570   (reb-do-update reb-subexp-displayed))
 571
 572 (defun reb-kill-buffer ()
 573   "When the RE Builder buffer is killed make sure no overlays stay around."
 574
 575   (when (reb-mode-buffer-p)
 576     (reb-delete-overlays)))
 577
 578
 579 ;; The next functions are the interface between the regexp and
 580 ;; its textual representation in the RE Builder buffer.
 581 ;; They are the only functions concerned with the actual syntax
 582 ;; being used.
 583 (defun reb-read-regexp ()
 584   "Read current RE."
 585   (save-excursion
 586     (cond ((eq reb-re-syntax 'read)
 587            (goto-char (point-min))
 588            (read (current-buffer)))
 589           ((eq reb-re-syntax 'string)
 590            (goto-char (point-min))
 591            (re-search-forward "\"")
 592            (let ((beg (point)))
 593              (goto-char (point-max))
 594              (re-search-backward "\"")
 595              (buffer-substring-no-properties beg (point))))
 596           ((reb-lisp-syntax-p)
 597            (buffer-string)))))
 598
 599 (defun reb-empty-regexp ()
 600   "Return empty RE for current syntax."
 601   (cond ((reb-lisp-syntax-p) "'()")
 602         (t "")))
 603
 604 (defun reb-insert-regexp ()
 605   "Insert current RE."
 606
 607   (let ((re (or (reb-target-binding reb-regexp)
 608                 (reb-empty-regexp))))
 609   (cond ((eq reb-re-syntax 'read)
 610          (print re (current-buffer)))
 611         ((eq reb-re-syntax 'string)
 612          (insert "\n\"" re "\""))
 613         ;; For the Lisp syntax we need the "source" of the regexp
 614         ((reb-lisp-syntax-p)
 615          (insert (or (reb-target-binding reb-regexp-src)
 616                      (reb-empty-regexp)))))))
 617
 618 (defun reb-cook-regexp (re)
 619   "Return RE after processing it according to `reb-re-syntax'."
 620   (cond ((memq reb-re-syntax '(sregex rx))
 621          (rx-to-string (eval (car (read-from-string re)))))
 622         (t re)))
 623
 624 (defun reb-update-regexp ()
 625   "Update the regexp for the target buffer.
 626 Return t if the (cooked) expression changed."
 627   (let* ((re-src (reb-read-regexp))
 628          (re (reb-cook-regexp re-src)))
 629     (with-current-buffer reb-target-buffer
 630       (let ((oldre reb-regexp))
 631         (prog1
 632             (not (string= oldre re))
 633           (setq reb-regexp re)
 634           ;; Only update the source re for the lisp formats
 635           (when (reb-lisp-syntax-p)
 636             (setq reb-regexp-src re-src)))))))
 637
 638
 639 ;; And now the real core of the whole thing
 640 (defun reb-count-subexps (re)
 641   "Return number of sub-expressions in the regexp RE."
 642
 643   (let ((i 0) (beg 0))
 644     (while (string-match "\\\\(" re beg)
 645       (setq i (1+ i)
 646             beg (match-end 0)))
 647     i))
 648
 649 (defun reb-update-overlays (&optional subexp)
 650   "Switch to `reb-target-buffer' and mark all matches of `reb-regexp'.
 651 If SUBEXP is non-nil mark only the corresponding sub-expressions."
 652   (let* ((re (reb-target-binding reb-regexp))
 653          (subexps (reb-count-subexps re))
 654          (matches 0)
 655          (submatches 0)
 656          firstmatch)
 657     (with-current-buffer reb-target-buffer
 658       (reb-delete-overlays)
 659       (goto-char (point-min))
 660       (while (and (not (eobp))
 661                   (re-search-forward re (point-max) t)
 662                   (or (not reb-auto-match-limit)
 663                       (< matches reb-auto-match-limit)))
 664         (when (and (= 0 (length (match-string 0)))
 665                    (not (eobp)))
 666           (forward-char 1))
 667         (let ((i 0)
 668               suffix max-suffix)
 669           (setq matches (1+ matches))
 670           (while (<= i subexps)
 671             (when (and (or (not subexp) (= subexp i))
 672                        (match-beginning i))
 673               (let ((overlay (make-overlay (match-beginning i)
 674                                            (match-end i)))
 675                     ;; When we have exceeded the number of provided faces,
 676                     ;; cycle thru them where `max-suffix' denotes the maximum
 677                     ;; suffix for `reb-match-*' that has been defined and
 678                     ;; `suffix' the suffix calculated for the current match.
 679                     (face
 680                      (cond
 681                        (max-suffix
 682                         (if (= suffix max-suffix)
 683                             (setq suffix 1)
 684                           (setq suffix (1+ suffix)))
 685                         (intern-soft (format "reb-match-%d" suffix)))
 686                        ((intern-soft (format "reb-match-%d" i)))
 687                        ((setq max-suffix (1- i))
 688                         (setq suffix 1)
 689                         ;; `reb-match-1' must exist.
 690                         'reb-match-1))))
 691                 (unless firstmatch (setq firstmatch (match-data)))
 692                 (setq reb-overlays (cons overlay reb-overlays)
 693                       submatches (1+ submatches))
 694                 (overlay-put overlay 'face face)
 695                 (overlay-put overlay 'priority i)))
 696             (setq i (1+ i))))))
 697     (let ((count (if subexp submatches matches)))
 698       (message "%s %smatch%s%s"
 699                (if (= 0 count) "No" (int-to-string count))
 700                (if subexp "subexpression " "")
 701                (if (= 1 count) "" "es")
 702                (if (and reb-auto-match-limit
 703                         (= reb-auto-match-limit count))
 704                    " (limit reached)" "")))
 705     (when firstmatch
 706       (store-match-data firstmatch)
 707       (reb-show-subexp (or subexp 0)))))
 708
 709 ;; The End
 710 (defun re-builder-unload-function ()
 711   "Unload the RE Builder library."
 712   (when (buffer-live-p (get-buffer reb-buffer))
 713     (with-current-buffer reb-buffer
 714       (remove-hook 'after-change-functions 'reb-auto-update t)
 715       (remove-hook 'kill-buffer-hook 'reb-kill-buffer t)
 716       (when (reb-mode-buffer-p)
 717         (reb-delete-overlays))))
 718   ;; continue standard unloading
 719   nil)
 720
 721 (provide 're-builder)
 722
 723 ;;; re-builder.el ends here