site-lisp/rhtml/rhtml-erb.el

   1 ;;;
   2 ;;; rhtml-erb.el - ERB tag support for `rhtml-mode'
   3 ;;;
   4
   5 ;; ***** BEGIN LICENSE BLOCK *****
   6 ;; Version: MPL 1.1/GPL 2.0/LGPL 2.1
   7
   8 ;; The contents of this file are subject to the Mozilla Public License Version
   9 ;; 1.1 (the "License"); you may not use this file except in compliance with
  10 ;; the License. You may obtain a copy of the License at
  11 ;; http://www.mozilla.org/MPL/
  12
  13 ;; Software distributed under the License is distributed on an "AS IS" basis,
  14 ;; WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  15 ;; for the specific language governing rights and limitations under the
  16 ;; License.
  17
  18 ;; The Original Code is ERB Tag Support for RHTML-MODE.
  19
  20 ;; The Initial Developer of the Original Code is
  21 ;; Paul Nathan Stickney <pstickne@gmail.com>.
  22 ;; Portions created by the Initial Developer are Copyright (C) 2006
  23 ;; the Initial Developer. All Rights Reserved.
  24
  25 ;; Contributor(s):
  26
  27 ;; Alternatively, the contents of this file may be used under the terms of
  28 ;; either the GNU General Public License Version 2 or later (the "GPL"), or
  29 ;; the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  30 ;; in which case the provisions of the GPL or the LGPL are applicable instead
  31 ;; of those above. If you wish to allow use of your version of this file only
  32 ;; under the terms of either the GPL or the LGPL, and not to allow others to
  33 ;; use your version of this file under the terms of the MPL, indicate your
  34 ;; decision by deleting the provisions above and replace them with the notice
  35 ;; and other provisions required by the GPL or the LGPL. If you do not delete
  36 ;; the provisions above, a recipient may use your version of this file under
  37 ;; the terms of any one of the MPL, the GPL or the LGPL.
  38
  39 ;; ***** END LICENSE BLOCK *****
  40
  41
  42 ;;; History
  43 ;; 2006SEP12 - Created
  44
  45 ;; Brief note on conventions:
  46 ;; DELIM - refers to the things like <% and %>
  47 ;; TAG - refers to entire <%ERB%> area, -including- the delims
  48
  49 ;; (load-file "~/.emacs.d/macro-utils.el")
  50 ;; (defmacro symbol-name-or-nil (symbol)
  51 ;;   (once-only (symbol)
  52 ;;     `(if ,symbol (symbol-name ,symbol))))
  53 ;; (put 'symbol-name-or-nil 'lisp-indent-function 1)
  54
  55
  56 (defconst rhtml-erb-open-delim
  57   "<%"
  58   "ERB opening tag.
  59 Due to implementation of `sgml-mode', this absolutely must begin with a
  60 < and be at least two characters long to work correctly.")
  61
  62 (defconst rhtml-erb-close-delim
  63   "%>"
  64   "ERB ending tag.
  65 I don't think this has any restrictions.")
  66
  67 (defconst rhtml-erb-open-delim-len
  68   (length rhtml-erb-open-delim))
  69
  70 (defconst rhtml-erb-close-delim-len
  71   (length rhtml-erb-open-delim))
  72
  73 (defconst rhtml-erb-delim-re
  74   (concat rhtml-erb-open-delim "\\|" rhtml-erb-close-delim))
  75
  76 (defconst rhtml-erb-tag-open-re
  77   (concat rhtml-erb-open-delim "\\(?:-=\\|[=#]?\\)?"))
  78
  79 ;; specific tags
  80 (defconst rhtml-erb-exec-tag-open-re
  81   (concat rhtml-erb-open-delim "\\(?:-\\(?:[^=#]\\|$\\)\\|[^-=#]\\|$\\)")
  82   "<%, and who would have thought it would be so complicated?")
  83 (defconst rhtml-erb-out-tag-open-re
  84   (concat rhtml-erb-open-delim "-?=")
  85   "<%=")
  86 (defconst rhtml-erb-comment-tag-open-re
  87   (concat rhtml-erb-open-delim "-?#")
  88   "<%#")
  89
  90 (defconst rhtml-erb-tag-body-re
  91   "\\(?:.\\|\n\\)*?")
  92
  93 (defconst rhtml-erb-tag-close-re
  94   (concat "-?" rhtml-erb-close-delim))
  95
  96 (defconst rhtml-erb-tag-re
  97   (concat "\\(" rhtml-erb-tag-open-re "\\)"
  98           "\\(" rhtml-erb-tag-body-re "\\)"
  99           "\\(" rhtml-erb-tag-close-re "\\)"))
 100
 101 (defun rhtml-erb-delim-type (start-delim)
 102   "Return `exec', `out', `comment' or nil dependin on the type of delimeter this is."
 103   (flet ((match? (regex)
 104                  (eq (string-match regex start-delim) 0)))
 105     (cond ((match? rhtml-erb-exec-tag-open-re)
 106            'exec)
 107           ((match? rhtml-erb-out-tag-open-re)
 108            'out)
 109           ((match? rhtml-erb-comment-tag-open-re)
 110            'comment))))
 111
 112 (defun rhtml-erb-middle-offset (prev-line-start cur-line-start)
 113   "Helper method for modified `sgml-calculate-indent'.
 114 Calculates adjustment of branches like \"else\".  PREV-LINE-START
 115 and CUR-LINE-START should be the first non-white space on each
 116 line, respectively."
 117   (save-excursion
 118     (+ (progn
 119          (goto-char cur-line-start)
 120          (if (rhtml-scan-for-erb-tags '(erb-middle)) sgml-basic-offset 0))
 121        (progn
 122          (goto-char prev-line-start)
 123          (if (rhtml-scan-for-erb-tags '(erb-middle)) (- sgml-basic-offset) 0)))))
 124
 125 (defconst rhtml-erb-block-open-re
 126   (concat "[A-Za-z_)][ ]+do[ ]+\\(?:|[A-Za-z_, ]*|\\)?[ ]*" rhtml-erb-tag-close-re))
 127
 128 (defconst rhtml-erb-brace-block-open-re
 129   (concat "[ ]+{[ ]+\\(?:|[A-Za-z_, ]*|\\)?[ ]*" rhtml-erb-tag-close-re)
 130   "Slightly less strictive to allow for \"hash = {\n\".")
 131
 132 (defmacro rhtml-erb-block-open-p ()
 133   "Guess if a Ruby fragment opens a block with do.
 134 Returns `block' or `brace-block' on success."
 135   `(re-search-forward ,rhtml-erb-block-open-re nil t))
 136
 137 (defmacro rhtml-erb-brace-block-open-p ()
 138   "Guess if a Ruby fragment opens a brace block (with {)
 139 Returns `block' or `brace-block' on success."
 140   `(re-search-forward ,rhtml-erb-brace-block-open-re nil t))
 141
 142 (defun rhtml-at-erb-tag-p ()
 143   "Returns (TAG-START . TAG-END) if at beginning of ERB tag."
 144   (if (looking-at rhtml-erb-tag-re)
 145       (cons (match-beginning 0) (match-end 0))))
 146
 147 (defun rhtml-skip-erb-tag ()
 148   "Skips over an ERB tag starting at (POINT); returns non-nil if succesful.
 149 If the search is successful (POINT) will be advanced."
 150   (let ((found (rhtml-at-erb-tag-p)))
 151     (when found
 152       (goto-char (cdr found)))))
 153
 154 (defun rhtml-erb-tag-type-p (type)
 155   (memq type '(erb-open erb-middle erb-close erb-data)))
 156
 157 (defun rhtml-scan-for-erb-tags (tags)
 158   "Like `rhtml-scan-erb-tag' but will only return (ERB-TYPE . NAME)
 159 if (memq ERB-TYPE tags)."
 160   (let ((start (point))
 161         (tag-info (rhtml-scan-erb-tag)))
 162     (if (memq (car tag-info) tags)
 163         tag-info
 164       ;; reset on failure
 165       (goto-char start)
 166       nil)))
 167
 168
 169 (defun rhtml-scan-erb-tag ()
 170   "Scans an ERB tag moving (POINT) to the end and returning (ERB-TYPE . NAME) on success.
 171 ERB-TYPE is `erb-open', `erb-data', `erb-middle', or `erb-close'.
 172 NAME is something like \"erb-brace-block\" or \"erb-start-form-tag\" that is
 173 used for level-matching."
 174   (let* ((erb-tag (rhtml-at-erb-tag-p))
 175          (erb-tag-end (cdr erb-tag)))
 176     (cond (erb-tag
 177            ;; Lead-in
 178            (looking-at rhtml-erb-tag-open-re)
 179            (goto-char (match-end 0))
 180            (skip-whitespace-forward)
 181            (prog1
 182                (save-restriction
 183                  (narrow-to-region (point) erb-tag-end) ;(- end 2))
 184                  (cond ((looking-at "if \\|unless ")
 185                         (cons 'erb-open "erb-multi-block"))
 186                        ((looking-at "for\\b\\|while ")
 187                         (cons 'erb-open "erb-block"))
 188                        ((rhtml-erb-block-open-p)
 189                         (cons 'erb-open "erb-block"))
 190                        ((rhtml-erb-brace-block-open-p)
 191                         (cons 'erb-open "erb-brace-block"))
 192                        ((looking-at "else \\|elsif")
 193                         (cons 'erb-middle "erb-middle"))
 194                        ((looking-at "end\\b")
 195                         (cons 'erb-close "erb-block"))
 196                        ((looking-at "}")
 197                         (cons 'erb-close "erb-brace-block"))
 198                        ((looking-at "start_form_tag\\b")
 199                         (cons 'erb-open "erb-form-tag"))
 200                        ((looking-at "end_form_tag\\b")
 201                         (cons 'erb-close "erb-form-tag"))
 202                        (t
 203                         (cons 'erb-data "erb-data"))))
 204              (goto-char erb-tag-end)))
 205         (t ;no match
 206          (cons nil nil)))))
 207
 208 ;; TODO - simply by removing point parameter
 209 (defun rhtml-erb-tag-region (&optional point)
 210   "If inside a ERB tag returns (START . END) of the tag, otherwise nil.
 211 If POINT is specified it will be used instead of (POINT)."
 212   (if point
 213       (save-excursion
 214         (goto-char point)
 215         (rhtml-erb-tag-region))
 216     (let ((prev (save-excursion ; -> (STR . START)
 217                   (skip-chars-forward rhtml-erb-open-delim)
 218                   (when (re-search-backward rhtml-erb-delim-re nil t)
 219                     (cons (match-string 0) (match-beginning 0)))))
 220           (next (save-excursion ; -> (STR . END)
 221                   (skip-chars-backward rhtml-erb-open-delim)
 222                   (when (re-search-forward rhtml-erb-delim-re nil t)
 223                     (cons (match-string 0) (match-end 0))))))
 224       ;; limit matches to valid regions
 225       (when (and (string= (car prev) rhtml-erb-open-delim)
 226                  (string= (car next) rhtml-erb-close-delim))
 227         (cons (cdr prev) (cdr next))))))
 228
 229 (defun rhtml-erb-regions (begin end)
 230   "Returns a list of elements in the form (TYPE START END) where type is
 231 `exec', `comment', `out'."
 232   (let* (tag-start regions last-tag-end)
 233     (catch 'done
 234       (save-excursion
 235         (goto-char begin)
 236         (while t
 237           (when (not (search-forward rhtml-erb-open-delim end t))
 238             (throw 'done regions))
 239           (setq tag-start (- (point) 2))
 240           (when (not (search-forward rhtml-erb-close-delim end t))
 241             (throw 'done regions))
 242           ;; erb tag
 243           (push (list
 244                  (case (char-after (+ tag-start 2))
 245                    (?= 'out) (?# 'comment) (t 'exec))
 246                  tag-start (point))
 247                 regions))))))
 248
 249 ;; PST -- what is the point? At the very least it needs a better name.
 250 (defun rhtml-erb-regions2 (begin end)
 251   "Returns a list of elements in the form (TYPE START END) where type is
 252 `exec', `comment', `out' or, for non-ERb secions, `other'."
 253   (let* (tag-start regions last-tag-end)
 254     (catch 'done
 255       (save-excursion
 256         (goto-char begin)
 257         (while t
 258
 259           (when (not (search-forward rhtml-erb-open-delim end t))
 260             ;; no more erb tags
 261             (push (list 'other (or last-tag-end begin) end)
 262                   regions)
 263             (throw 'done regions))
 264           (setq tag-start (- (point) 2))
 265
 266           (when (not (search-forward rhtml-erb-close-delim end t))
 267             (throw 'done regions))
 268           ;; other section
 269           ;; PST -- may catch partial start tag
 270           (when (> (point) (or last-tag-end begin))
 271             (push (list 'other begin (point))
 272                   regions))
 273           (setq last-tag-end (point))
 274
 275           ;; erb tag
 276           (push (list
 277                  (case (char-after (+ tag-start 2))
 278                    (?= 'out) (?# 'comment) (t 'exec))
 279                  tag-start (point))
 280                 regions))))))
 281
 282 (defun rhtml-union-region-containing-erb-tags (r-start r-end)
 283   "Returns (START . END) for a region which is an aggregate of
 284 the region defined by R-START, R-END and any ERB tags which
 285 start, stop, or are contained in the region."
 286   (let* ((unopened-tag (rhtml-erb-tag-region r-start))
 287          (unclosed-tag (rhtml-erb-tag-region r-end))
 288          (new-start (or (and unopened-tag (car unopened-tag)) r-start))
 289          (new-end (or (and unclosed-tag (cdr unclosed-tag)) r-end)))
 290     (cons new-start new-end)))
 291
 292 (defun rhtml-widen-to-erb-tag ()
 293   "Widens the buffer to the ERB tag.
 294 If no ERB tag is found the buffer will be reset to pre-state.
 295 The point is advanced to the beginning of the new region (even if no ERB found)."
 296   (let ((r-start (point-min))
 297         (r-end (point-max)))
 298     (widen)
 299     (let ((region (rhtml-erb-tag-region)))
 300       (when region
 301         (setq r-start (car region))
 302         (setq r-end (cdr region)))
 303       (narrow-to-region r-start r-end)
 304       (goto-char (point-min)))))
 305
 306 (defun rhtml-region-has-erb-tag-p (start end)
 307   "Returns non-nil if the region bounded by START and END
 308 contains an ERB tag."
 309   (save-excursion
 310     (goto-char start)
 311     (re-search-forward rhtml-erb-tag-re end t)))
 312
 313
 314 ;; utility functions
 315
 316 (defun skip-whitespace-forward ()
 317   "Skip forward common ([ \t\r\n]) whitespace."
 318   (skip-chars-forward " \t\r\n"))
 319
 320 ;;
 321 (provide 'rhtml-erb)