code.delx.au - gnu-emacs-elpa/blob - yasnippet.el

   1 ;;; yasnippet.el --- Yet another snippet extension for Emacs.
   2
   3 ;; Author: pluskid <pluskid@gmail.com>
   4 ;; Version: 0.1
   5
   6 ;; This file is free software; you can redistribute it and/or modify
   7 ;; it under the terms of the GNU General Public License as published by
   8 ;; the Free Software Foundation; either version 2, or (at your option)
   9 ;; any later version.
  10
  11 ;; This file is distributed in the hope that it will be useful,
  12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;; GNU General Public License for more details.
  15
  16 ;; You should have received a copy of the GNU General Public License
  17 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  18 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 ;; Boston, MA 02111-1307, USA.
  20
  21 ;;; Commentary:
  22
  23 ;; Nothing.
  24
  25 (require 'cl)
  26
  27 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  28 ;; User customizable variables
  29 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  30 (defvar yas/key-syntax "w"
  31   "Syntax of a key. This is used to determine the current key being
  32 expanded.")
  33
  34 (defvar yas/indent-line t
  35   "Each (except the 1st) line of the snippet template is indented to
  36 current column if this variable is non-`nil'.")
  37 (make-variable-buffer-local 'yas/indent-line)
  38
  39 (defvar yas/keymap (make-sparse-keymap)
  40   "The keymap of snippet.")
  41 (define-key yas/keymap (kbd "TAB") 'yas/next-field-group)
  42 (define-key yas/keymap (kbd "S-TAB") 'yas/prev-field-group)
  43 (define-key yas/keymap (kbd "<S-iso-lefttab>") 'yas/prev-field-group)
  44 (define-key yas/keymap (kbd "<S-tab>") 'yas/prev-field-group)
  45
  46 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  47 ;; Internal variables
  48 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  49 (defvar yas/snippet-tables (make-hash-table)
  50   "A hash table of snippet tables corresponding to each major-mode.")
  51
  52 (defconst yas/escape-backslash
  53   (concat "YASESCAPE" "BACKSLASH" "PROTECTGUARD"))
  54 (defconst yas/escape-dollar
  55   (concat "YASESCAPE" "DOLLAR" "PROTECTGUARD"))
  56 (defconst yas/escape-backquote
  57   (concat "YASESCAPE" "BACKQUOTE" "PROTECTGUARD"))
  58
  59 (defconst yas/field-regexp
  60   (concat "$\\(?1:[0-9]+\\)" "\\|"
  61           "${\\(?:\\(?1:[0-9]+\\):\\)?\\(?2:[^}]*\\)}"))
  62
  63 (defvar yas/snippet-id-seed 0
  64   "Contains the next id for a snippet")
  65 (defun yas/snippet-next-id ()
  66   (let ((id yas/snippet-id-seed))
  67     (incf yas/snippet-id-seed)
  68     id))
  69
  70 (defun yas/snippet-new ()
  71   "Create a new snippet."
  72   (cons nil (cons nil (yas/snippet-next-id))))
  73 (defun yas/snippet-field-groups (snippet)
  74   "Get field groups of SNIPPET."
  75   (car snippet))
  76 (defun yas/snippet-field-groups-set (snippet groups)
  77   "Set field groups of SNIPPET."
  78   (setf (car snippet) groups))
  79 (defun yas/snippet-exit-marker-set (snippet marker)
  80   "Set exit marker of SNIPPET."
  81   (setf (cadr snippet) marker))
  82 (defun yas/snippet-exit-marker (snippet)
  83   "Get exit marker of SNIPPET."
  84   (cadr snippet))
  85 (defun yas/snippet-id (snippet)
  86   "Get id of the snippet."
  87   (cddr snippet))
  88 (defun yas/snippet-add-field (snippet field)
  89   "Add FIELD to SNIPPET."
  90   (let ((group (find field
  91                      (yas/snippet-field-groups snippet)
  92                      :test
  93                      '(lambda (field group)
  94                         (= (yas/snippet-field-number field)
  95                            (yas/snippet-field-group-number group))))))
  96     (if group
  97         (yas/snippet-field-group-add group field)
  98       (push (yas/snippet-field-group-new field)
  99             (car snippet)))))
 100
 101 (defun yas/snippet-field-group-new (field)
 102   "Create a new field group."
 103   (list field             ; primary field
 104         (list field)      ; fields
 105         nil               ; next field group
 106         nil))             ; prev field group
 107 (defun yas/snippet-field-group-primary (group)
 108   "Get the primary field of this group."
 109   (car group))
 110 (defun yas/snippet-field-group-fields (group)
 111   "Get all fields belonging to this group."
 112   (cadr group))
 113 (defun yas/snippet-field-group-set-next (group next)
 114   "Set next field group of GROUP."
 115   (setf (nth 2 group) next))
 116 (defun yas/snippet-field-group-next (group)
 117   "Get next field group."
 118   (nth 2 group))
 119 (defun yas/snippet-field-group-set-prev (group prev)
 120   "Set previous field group of GROUP."
 121   (setf (nth 3 group) prev))
 122 (defun yas/snippet-field-group-prev (group)
 123   "Get previous field group."
 124   (nth 3 group))
 125 (defun yas/snippet-field-group-value (group)
 126   "Get the default value of the field group."
 127   (or (yas/snippet-field-value
 128        (yas/snippet-field-group-primary group))
 129       ""))
 130 (defun yas/snippet-field-group-number (group)
 131   "Get the number of the field group."
 132   (yas/snippet-field-number
 133    (yas/snippet-field-group-primary group)))
 134 (defun yas/snippet-field-group-add (group field)
 135   "Add a field to the field group. If the value of the primary
 136 field is nil and that of the field is not nil, the field is set
 137 as the primary field of the group."
 138   (push field (nth 1 group))
 139   (when (and (null (yas/snippet-field-value (car group)))
 140              (yas/snippet-field-value field))
 141     (setf (car group) field)))
 142
 143 (defun yas/snippet-field-new (overlay number value)
 144   "Create a new snippet-field."
 145   (cons overlay (cons number value)))
 146 (defun yas/snippet-field-overlay (field)
 147   "Get the overlay of the field."
 148   (car field))
 149 (defun yas/snippet-field-number (field)
 150   "Get the number of the field."
 151   (cadr field))
 152 (defun yas/snippet-field-value (field)
 153   "Get the value of the field."
 154   (cddr field))
 155 (defun yas/snippet-field-compare (field1 field2)
 156   "Compare two fields. The field with a number is sorted first.
 157 If they both have a number, compare through the number. If neither
 158 have, compare through the start point of the overlay."
 159   (let ((n1 (yas/snippet-field-number field1))
 160         (n2 (yas/snippet-field-number field2)))
 161     (if n1
 162         (if n2
 163             (< n1 n2)
 164           t)
 165       (if n2
 166           nil
 167         (< (overlay-start (yas/snippet-field-overlay field1))
 168            (overlay-start (yas/snippet-field-overlay field2)))))))
 169
 170 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 171 ;; Internal functions
 172 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 173 (defun yas/eval-string (string)
 174   "Evaluate STRING and convert the result to string."
 175   (condition-case err
 176       (format "%s" (eval (read string)))
 177     (error (format "(error in elisp evaluation: %s)"
 178                    (error-message-string err)))))
 179 (defsubst yas/replace-all (from to)
 180   "Replace all occurance from FROM to TO."
 181   (goto-char (point-min))
 182   (while (search-forward from nil t)
 183     (replace-match to t t)))
 184 (defun yas/snippet-table (mode)
 185   "Get the snippet table corresponding to MODE."
 186   (let ((table (gethash mode yas/snippet-tables)))
 187     (unless table
 188       (setq table (make-hash-table :test 'equal))
 189       (puthash mode table yas/snippet-tables))
 190     table))
 191 (defsubst yas/current-snippet-table ()
 192   "Get the snippet table for current major-mode."
 193   (yas/snippet-table major-mode))
 194
 195 (defsubst yas/template (key snippet-table)
 196   "Get template for KEY in SNIPPET-TABLE."
 197   (gethash key snippet-table))
 198
 199 (defun yas/current-key ()
 200   "Get the key under current position."
 201   (let ((start (point))
 202         (end (point)))
 203     (save-excursion
 204       (skip-syntax-backward yas/key-syntax)
 205       (setq start (point))
 206       (list (buffer-substring-no-properties start end)
 207             start
 208             end))))
 209
 210 (defun yas/expand-snippet (start end template)
 211   "Expand snippet at current point. Text between START and END
 212 will be deleted before inserting template."
 213   (goto-char start)
 214
 215   (let ((length (- end start))
 216         (column (current-column)))
 217   (save-restriction
 218     (narrow-to-region start start)
 219
 220     (insert template)
 221     ;; Step 1: do necessary indent
 222     (when yas/indent-line
 223       (let* ((indent (if indent-tabs-mode
 224                          (concat (make-string (/ column tab-width) ?\t)
 225                                  (make-string (% column tab-width) ?\ ))
 226                        (make-string column ?\ ))))
 227         (goto-char (point-min))
 228         (while (and (zerop (forward-line))
 229                     (= (current-column) 0))
 230           (insert indent))))
 231
 232     ;; Step 2: protect backslash and backquote
 233     (yas/replace-all "\\\\" yas/escape-backslash)
 234     (yas/replace-all "\\`" yas/escape-backquote)
 235
 236     ;; Step 3: evaluate all backquotes
 237     (goto-char (point-min))
 238     (while (re-search-forward "`\\([^`]*\\)`" nil t)
 239       (replace-match (yas/eval-string (match-string-no-properties 1))
 240                      t t))
 241
 242     ;; Step 4: protect all escapes, including backslash and backquot
 243     ;; which may be produced in Step 3
 244     (yas/replace-all "\\\\" yas/escape-backslash)
 245     (yas/replace-all "\\`" yas/escape-backquote)
 246     (yas/replace-all "\\$" yas/escape-dollar)
 247
 248     (let ((snippet (yas/snippet-new)))
 249       ;; Step 5: Create fields
 250       (goto-char (point-min))
 251       (while (re-search-forward yas/field-regexp nil t)
 252         (let ((number (match-string-no-properties 1)))
 253           (if (and number
 254                    (string= "0" number))
 255               (progn
 256                 (replace-match "")
 257                 (yas/snippet-exit-marker-set
 258                  snippet
 259                  (copy-marker (point) t)))
 260             (yas/snippet-add-field
 261              snippet
 262              (yas/snippet-field-new
 263               (make-overlay (match-beginning 0) (match-end 0))
 264               (and number (string-to-number number))
 265               (match-string-no-properties 2))))))
 266
 267       ;; Step 6: Sort and link each field group
 268       (yas/snippet-field-groups-set
 269        snippet
 270        (sort (yas/snippet-field-groups snippet)
 271              '(lambda (group1 group2)
 272                 (yas/snippet-field-compare
 273                  (yas/snippet-field-group-primary group1)
 274                  (yas/snippet-field-group-primary group2)))))
 275       (let ((prev nil))
 276         (dolist (group (yas/snippet-field-groups snippet))
 277           (yas/snippet-field-group-set-prev group prev)
 278           (when prev
 279             (yas/snippet-field-group-set-next prev group))
 280           (setq prev group)))
 281
 282       ;; Step 7: Set up properties of overlays, including keymaps
 283       (dolist (group (yas/snippet-field-groups snippet))
 284         (let ((overlay (yas/snippet-field-overlay
 285                         (yas/snippet-field-group-primary group))))
 286           (overlay-put overlay 'keymap yas/keymap)
 287           (overlay-put overlay 'yas/snippet snippet)
 288           (overlay-put overlay 'yas/snippet-field-group group)
 289           (dolist (field (yas/snippet-field-group-fields group))
 290             (overlay-put (yas/snippet-field-overlay field)
 291                          'face
 292                          'highlight))))
 293
 294       ;; Step 8: Replace fields with default values
 295       (dolist (group (yas/snippet-field-groups snippet))
 296         (let ((value (yas/snippet-field-group-value group)))
 297           (dolist (field (yas/snippet-field-group-fields group))
 298             (let* ((overlay (yas/snippet-field-overlay field))
 299                    (start (overlay-start overlay))
 300                    (end (overlay-end overlay))
 301                    (length (- end start)))
 302               (goto-char start)
 303               (insert value)
 304               (delete-char length)))))
 305
 306       ;; Step 9: restore all escape characters
 307       (yas/replace-all yas/escape-dollar "$")
 308       (yas/replace-all yas/escape-backquote "`")
 309       (yas/replace-all yas/escape-backslash "\\")
 310
 311       ;; Step 10: move to end and make sure exit-marker exist
 312       (goto-char (point-max))
 313       (unless (yas/snippet-exit-marker snippet)
 314         (yas/snippet-exit-marker-set snippet (copy-marker (point) t)))
 315
 316       ;; Step 11: remove the trigger key
 317       (widen)
 318       (delete-char length)
 319
 320       ;; Step 12: place the cursor at a proper place
 321       (let ((groups (yas/snippet-field-groups snippet))
 322             (exit-marker (yas/snippet-exit-marker snippet)))
 323         (if groups
 324             (goto-char (overlay-start
 325                         (yas/snippet-field-overlay
 326                          (yas/snippet-field-group-primary
 327                           (car groups)))))
 328           ;; no need to call exit-snippet, since no overlay created.
 329           (goto-char exit-marker)))))))
 330
 331 (defun yas/current-snippet-overlay ()
 332   "Get the most proper overlay which is belongs to a snippet."
 333   (let ((snippet-overlay nil))
 334     (dolist (overlay (overlays-at (point)))
 335       (when (overlay-get overlay 'yas/snippet)
 336         (if (null snippet-overlay)
 337             (setq snippet-overlay overlay)
 338           (when (> (yas/snippet-id (overlay-get overlay 'yas/snippet))
 339                    (yas/snippet-id (overlay-get snippet-overlay 'yas/snippet)))
 340             (setq snippet-overlay overlay)))))
 341     snippet-overlay))
 342
 343 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 344 ;; User level functions
 345 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 346 (defun yas/define (mode key template)
 347   "Define a snippet. Expanding KEY into TEMPLATE."
 348   (puthash key template (yas/snippet-table mode)))
 349
 350 (defun yas/expand ()
 351   "Expand a snippet. When a snippet is expanded, t is returned,
 352 otherwise, nil returned."
 353   (interactive)
 354   (multiple-value-bind (key start end) (yas/current-key)
 355     (let ((template (yas/template key (yas/current-snippet-table))))
 356       (if template
 357           (progn
 358             (yas/expand-snippet start end template)
 359             t)
 360         nil))))
 361
 362 (defun yas/next-field-group ()
 363   "Navigate to next field group. If there's none, exit the snippet."
 364   (interactive)
 365   (let ((overlay (yas/current-snippet-overlay)))
 366     (if overlay
 367         (let ((next (yas/snippet-field-group-next
 368                      (overlay-get overlay 'yas/snippet-field-group))))
 369           (if next
 370               (goto-char (overlay-start
 371                           (yas/snippet-field-overlay
 372                            (yas/snippet-field-group-primary next))))
 373             (yas/exit-snippet (overlay-get overlay 'yas/snippet))))
 374       (message "Not in a snippet field."))))
 375
 376 (defun yas/prev-field-group ()
 377   "Navigate to prev field group. If there's none, exit the snippet."
 378   (interactive)
 379   (let ((overlay (yas/current-snippet-overlay)))
 380     (if overlay
 381         (let ((prev (yas/snippet-field-group-prev
 382                      (overlay-get overlay 'yas/snippet-field-group))))
 383           (if prev
 384               (goto-char (overlay-start
 385                           (yas/snippet-field-overlay
 386                            (yas/snippet-field-group-primary prev))))
 387             (yas/exit-snippet (overlay-get overlay 'yas/snippet))))
 388       (message "Not in a snippet field."))))
 389
 390 (defun yas/exit-snippet (snippet)
 391   "Goto exit-marker of SNIPPET and delete the snippet."
 392   (interactive)
 393   (goto-char (yas/snippet-exit-marker snippet))
 394   (dolist (group (yas/snippet-field-groups snippet))
 395     (dolist (field (yas/snippet-field-group-fields group))
 396       (delete-overlay (yas/snippet-field-overlay field)))))
 397
 398 (provide 'yasnippet)