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/trigger-key (kbd "TAB")
  40   "The key to bind as a trigger of snippet.")
  41 (defvar yas/trigger-fallback 'indent-according-to-mode
  42   "The fallback command to call when there's no snippet to expand.")
  43 (make-variable-buffer-local 'yas/trigger-fallback)
  44
  45 (defvar yas/keymap (make-sparse-keymap)
  46   "The keymap of snippet.")
  47 (define-key yas/keymap (kbd "TAB") 'yas/next-field-group)
  48 (define-key yas/keymap (kbd "S-TAB") 'yas/prev-field-group)
  49 (define-key yas/keymap (kbd "<S-iso-lefttab>") 'yas/prev-field-group)
  50 (define-key yas/keymap (kbd "<S-tab>") 'yas/prev-field-group)
  51
  52 (defvar yas/use-menu t
  53   "If this is set to `t', all snippet template of the current
  54 mode will be listed under the menu \"yasnippet\".")
  55 (defvar yas/trigger-symbol " =>"
  56   "The text that will be used in menu to represent the trigger.")
  57 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  58 ;; Internal variables
  59 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  60 (defvar yas/version "0.1")
  61
  62 (defvar yas/snippet-tables (make-hash-table)
  63   "A hash table of snippet tables corresponding to each major-mode.")
  64 (defvar yas/menu-table (make-hash-table)
  65   "A hash table of menus of corresponding major-mode.")
  66 (defvar yas/menu-keymap (make-sparse-keymap))
  67 ;; empty menu will cause problems, so we insert some items
  68 (define-key yas/menu-keymap [yas/about]
  69   '(menu-item "About" yas/about))
  70 (define-key yas/menu-keymap [yas/separator]
  71   '(menu-item "--"))
  72
  73 (defconst yas/escape-backslash
  74   (concat "YASESCAPE" "BACKSLASH" "PROTECTGUARD"))
  75 (defconst yas/escape-dollar
  76   (concat "YASESCAPE" "DOLLAR" "PROTECTGUARD"))
  77 (defconst yas/escape-backquote
  78   (concat "YASESCAPE" "BACKQUOTE" "PROTECTGUARD"))
  79
  80 (defconst yas/field-regexp
  81   (concat "$\\(?1:[0-9]+\\)" "\\|"
  82           "${\\(?:\\(?1:[0-9]+\\):\\)?\\(?2:[^}]*\\)}"))
  83
  84 (defvar yas/snippet-id-seed 0
  85   "Contains the next id for a snippet")
  86 (defun yas/snippet-next-id ()
  87   (let ((id yas/snippet-id-seed))
  88     (incf yas/snippet-id-seed)
  89     id))
  90
  91 (defvar yas/overlay-modification-hooks
  92   (list 'yas/overlay-modification-hook)
  93   "The list of hooks to the overlay modification event.")
  94 (defvar yas/overlay-insert-in-front-hooks
  95   (list 'yas/overlay-insert-in-front-hook)
  96   "The list of hooks of the overlay inserted in front event.")
  97 (defvar yas/overlay-insert-behind-hooks
  98   (list 'yas/overlay-insert-behind-hook)
  99   "The list of hooks of the overlay inserted behind event.")
 100
 101
 102 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 103 ;; Internal Structs
 104 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 105 (defstruct (yas/template (:constructor yas/make-template (content name)))
 106   "A template for a snippet."
 107   content
 108   name)
 109 (defstruct (yas/snippet (:constructor yas/make-snippet ()))
 110   "A snippet."
 111   (groups nil)
 112   (tabstops nil)    ; tabstops are those groups whose init value is empty
 113   (exit-marker nil)
 114   (id (yas/snippet-next-id) :read-only t)
 115   (overlay nil))
 116 (defstruct (yas/group (:constructor yas/make-group (primary-field snippet)))
 117   "A group contains a list of field with the same number."
 118   primary-field
 119   (fields (list primary-field))
 120   (next nil)
 121   (prev nil)
 122   snippet)
 123 (defstruct (yas/field (:constructor yas/make-field (overlay number value)))
 124   "A field in a snippet."
 125   overlay
 126   number
 127   value)
 128
 129 (defun yas/snippet-add-field (snippet field)
 130   "Add FIELD to SNIPPET."
 131   (let ((group (find field
 132                      (yas/snippet-groups snippet)
 133                      :test
 134                      '(lambda (field group)
 135                         (= (yas/field-number field)
 136                            (yas/group-number group))))))
 137     (if group
 138         (yas/group-add-field group field)
 139       (push (yas/make-group field snippet)
 140             (yas/snippet-groups snippet)))))
 141
 142 (defun yas/group-value (group)
 143   "Get the default value of the field group."
 144   (or (yas/field-value
 145        (yas/group-primary-field group))
 146       ""))
 147 (defun yas/group-number (group)
 148   "Get the number of the field group."
 149   (yas/field-number
 150    (yas/group-primary-field group)))
 151 (defun yas/group-add-field (group field)
 152   "Add a field to the field group. If the value of the primary
 153 field is nil and that of the field is not nil, the field is set
 154 as the primary field of the group."
 155   (push field (yas/group-fields group))
 156   (when (and (null (yas/field-value (yas/group-primary-field group)))
 157              (yas/field-value field))
 158     (setf (yas/group-primary-field group) field)))
 159
 160 (defun yas/snippet-field-compare (field1 field2)
 161   "Compare two fields. The field with a number is sorted first.
 162 If they both have a number, compare through the number. If neither
 163 have, compare through the start point of the overlay."
 164   (let ((n1 (yas/field-number field1))
 165         (n2 (yas/field-number field2)))
 166     (if n1
 167         (if n2
 168             (< n1 n2)
 169           t)
 170       (if n2
 171           nil
 172         (< (overlay-start (yas/field-overlay field1))
 173            (overlay-start (yas/field-overlay field2)))))))
 174
 175 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 176 ;; Internal functions
 177 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 178 (defun yas/eval-string (string)
 179   "Evaluate STRING and convert the result to string."
 180   (condition-case err
 181       (format "%s" (eval (read string)))
 182     (error (format "(error in elisp evaluation: %s)"
 183                    (error-message-string err)))))
 184 (defsubst yas/replace-all (from to)
 185   "Replace all occurance from FROM to TO."
 186   (goto-char (point-min))
 187   (while (search-forward from nil t)
 188     (replace-match to t t)))
 189
 190 (defun yas/snippet-table (mode)
 191   "Get the snippet table corresponding to MODE."
 192   (let ((table (gethash mode yas/snippet-tables)))
 193     (unless table
 194       (setq table (make-hash-table :test 'equal))
 195       (puthash mode table yas/snippet-tables))
 196     table))
 197 (defsubst yas/current-snippet-table ()
 198   "Get the snippet table for current major-mode."
 199   (yas/snippet-table major-mode))
 200
 201 (defun yas/menu-keymap-for-mode (mode)
 202   "Get the menu keymap correspondong to MODE."
 203   (let ((keymap (gethash mode yas/menu-table)))
 204     (unless keymap
 205       (setq table (make-sparse-keymap))
 206       (puthash mode keymap yas/menu-table))
 207     table))
 208
 209 (defsubst yas/template (key snippet-table)
 210   "Get template for KEY in SNIPPET-TABLE."
 211   (gethash key snippet-table))
 212
 213 (defun yas/current-key ()
 214   "Get the key under current position. A key is used to find
 215 the template of a snippet in the current snippet-table."
 216   (let ((start (point))
 217         (end (point)))
 218     (save-excursion
 219       (skip-syntax-backward yas/key-syntax)
 220       (setq start (point))
 221       (list (buffer-substring-no-properties start end)
 222             start
 223             end))))
 224
 225 (defun yas/synchronize-fields (field-group)
 226   "Update all fields' text according to the primary field."
 227   (save-excursion
 228     (let* ((inhibit-modification-hooks t)
 229            (primary (yas/group-primary-field field-group))
 230            (primary-overlay (yas/field-overlay primary))
 231            (text (buffer-substring-no-properties (overlay-start primary-overlay)
 232                                                  (overlay-end primary-overlay))))
 233       (dolist (field (yas/group-fields field-group))
 234         (let* ((field-overlay (yas/field-overlay field))
 235                (original-length (- (overlay-end field-overlay)
 236                                    (overlay-start field-overlay))))
 237           (unless (eq field-overlay primary-overlay)
 238             (goto-char (overlay-start field-overlay))
 239             (insert text)
 240             (if (= (overlay-start field-overlay)
 241                    (overlay-end field-overlay))
 242                 (move-overlay field-overlay
 243                               (overlay-start field-overlay)
 244                               (point))
 245               (delete-char original-length))))))))
 246
 247 (defun yas/overlay-modification-hook (overlay after? beg end &optional length)
 248   "Modification hook for snippet field overlay."
 249   (when (and after? (not undo-in-progress))
 250     (yas/synchronize-fields (overlay-get overlay 'yas/group))))
 251 (defun yas/overlay-insert-in-front-hook (overlay after? beg end &optional length)
 252   "Hook for snippet overlay when text is inserted in front of a snippet field."
 253   (when after?
 254     (let ((field-group (overlay-get overlay 'yas/group))
 255           (inhibit-modification-hooks t))
 256       (when (not (overlay-get overlay 'yas/modified?))
 257         (overlay-put overlay 'yas/modified? t)
 258         (when (> (overlay-end overlay) end)
 259           (save-excursion
 260             (goto-char end)
 261             (delete-char (- (overlay-end overlay) end)))))
 262      (yas/synchronize-fields field-group))))
 263 (defun yas/overlay-insert-behind-hook (overlay after? beg end &optional length)
 264   "Hook for snippet overlay when text is inserted just behind a snippet field."
 265   (when (and after?
 266              (null (yas/current-snippet-overlay beg))) ; not inside another field
 267     (move-overlay overlay
 268                   (overlay-start overlay)
 269                   end)
 270     (yas/synchronize-fields (overlay-get overlay 'yas/group))))
 271
 272 (defun yas/undo-expand-snippet (start end key snippet)
 273   "Undo a snippet expansion. Delete the overlays. This undo can't be
 274 redo-ed."
 275   (let ((undo (car buffer-undo-list)))
 276     (while (null undo)
 277       (setq buffer-undo-list (cdr buffer-undo-list))
 278       (setq undo (car buffer-undo-list)))
 279     ;; Remove this undo operation record
 280     (setq buffer-undo-list (cdr buffer-undo-list))
 281   (let ((inhibit-modification-hooks t)
 282         (buffer-undo-list t))
 283     (yas/exit-snippet snippet)
 284     (goto-char start)
 285     (delete-char (- end start))
 286     (insert key))))
 287
 288 (defun yas/expand-snippet (start end template)
 289   "Expand snippet at current point. Text between START and END
 290 will be deleted before inserting template."
 291   (goto-char start)
 292
 293   (let ((key (buffer-substring-no-properties start end))
 294         (original-undo-list buffer-undo-list)
 295         (inhibit-modification-hooks t)
 296         (length (- end start))
 297         (column (current-column)))
 298     (save-restriction
 299       (narrow-to-region start start)
 300
 301       (setq buffer-undo-list t)
 302       (insert template)
 303
 304       ;; Step 1: do necessary indent
 305       (when yas/indent-line
 306         (let* ((indent (if indent-tabs-mode
 307                            (concat (make-string (/ column tab-width) ?\t)
 308                                    (make-string (% column tab-width) ?\ ))
 309                          (make-string column ?\ ))))
 310           (goto-char (point-min))
 311           (while (and (zerop (forward-line))
 312                       (= (current-column) 0))
 313             (insert indent))))
 314
 315       ;; Step 2: protect backslash and backquote
 316       (yas/replace-all "\\\\" yas/escape-backslash)
 317       (yas/replace-all "\\`" yas/escape-backquote)
 318
 319       ;; Step 3: evaluate all backquotes
 320       (goto-char (point-min))
 321       (while (re-search-forward "`\\([^`]*\\)`" nil t)
 322         (replace-match (yas/eval-string (match-string-no-properties 1))
 323                        t t))
 324
 325       ;; Step 4: protect all escapes, including backslash and backquot
 326       ;; which may be produced in Step 3
 327       (yas/replace-all "\\\\" yas/escape-backslash)
 328       (yas/replace-all "\\`" yas/escape-backquote)
 329       (yas/replace-all "\\$" yas/escape-dollar)
 330
 331       (let ((snippet (yas/make-snippet)))
 332         ;; Step 5: Create fields
 333         (goto-char (point-min))
 334         (while (re-search-forward yas/field-regexp nil t)
 335           (let ((number (match-string-no-properties 1)))
 336             (if (and number
 337                      (string= "0" number))
 338                 (progn
 339                   (replace-match "")
 340                   (setf (yas/snippet-exit-marker snippet)
 341                         (copy-marker (point) t)))
 342               (yas/snippet-add-field
 343                snippet
 344                (yas/make-field
 345                 (make-overlay (match-beginning 0) (match-end 0))
 346                 (and number (string-to-number number))
 347                 (match-string-no-properties 2))))))
 348
 349         ;; Step 6: Sort and link each field group
 350         (setf (yas/snippet-groups snippet)
 351               (sort (yas/snippet-groups snippet)
 352                     '(lambda (group1 group2)
 353                        (yas/snippet-field-compare
 354                         (yas/group-primary-field group1)
 355                         (yas/group-primary-field group2)))))
 356         (let ((prev nil))
 357           (dolist (group (yas/snippet-groups snippet))
 358             (setf (yas/group-prev group) prev)
 359             (when prev
 360               (setf (yas/group-next prev) group))
 361             (setq prev group)))
 362
 363         ;; Step 7: Create keymap overlay for snippet
 364         (let ((overlay (make-overlay (point-min)
 365                                      (point-max)
 366                                      nil
 367                                      nil
 368                                      t)))
 369           (overlay-put overlay 'keymap yas/keymap)
 370           (overlay-put overlay 'yas/snippet-reference snippet)
 371           (setf (yas/snippet-overlay snippet) overlay))
 372
 373         ;; Step 8: Replace fields with default values
 374         (dolist (group (yas/snippet-groups snippet))
 375           (let ((value (yas/group-value group)))
 376             (when (string= "" value)
 377               (push group (yas/snippet-tabstops snippet)))
 378             (dolist (field (yas/group-fields group))
 379               (let* ((overlay (yas/field-overlay field))
 380                      (start (overlay-start overlay))
 381                      (end (overlay-end overlay))
 382                      (length (- end start)))
 383                 (goto-char start)
 384                 (insert value)
 385                 (delete-char length)))))
 386
 387         ;; Step 9: restore all escape characters
 388         (yas/replace-all yas/escape-dollar "$")
 389         (yas/replace-all yas/escape-backquote "`")
 390         (yas/replace-all yas/escape-backslash "\\")
 391
 392         ;; Step 10: Set up properties of overlays
 393         (dolist (group (yas/snippet-groups snippet))
 394           (let ((overlay (yas/field-overlay
 395                           (yas/group-primary-field group))))
 396             (overlay-put overlay 'yas/snippet snippet)
 397             (overlay-put overlay 'yas/group group)
 398             (overlay-put overlay 'yas/modified? nil)
 399             (overlay-put overlay 'modification-hooks yas/overlay-modification-hooks)
 400             (overlay-put overlay 'insert-in-front-hooks yas/overlay-insert-in-front-hooks)
 401             (overlay-put overlay 'insert-behind-hooks yas/overlay-insert-behind-hooks)
 402             (dolist (field (yas/group-fields group))
 403               (overlay-put (yas/field-overlay field)
 404                            'face
 405                            'highlight))))
 406
 407         ;; Step 11: move to end and make sure exit-marker exist
 408         (goto-char (point-max))
 409         (unless (yas/snippet-exit-marker snippet)
 410           (setf (yas/snippet-exit-marker snippet) (copy-marker (point) t)))
 411
 412         ;; Step 12: Construct undo information
 413         (unless (eq original-undo-list t)
 414           (add-to-list 'original-undo-list
 415                        `(apply yas/undo-expand-snippet
 416                                ,(point-min)
 417                                ,(point-max)
 418                                ,key
 419                                ,snippet)))
 420
 421         ;; Step 13: remove the trigger key
 422         (widen)
 423         (delete-char length)
 424
 425         ;; Step 14: place the cursor at a proper place
 426         (let ((groups (yas/snippet-groups snippet))
 427               (exit-marker (yas/snippet-exit-marker snippet)))
 428           (if groups
 429               (goto-char (overlay-start
 430                           (yas/field-overlay
 431                            (yas/group-primary-field
 432                             (car groups)))))
 433             ;; no need to call exit-snippet, since no overlay created.
 434             (goto-char exit-marker)))
 435
 436         (setq buffer-undo-list original-undo-list)))))
 437
 438 (defun yas/current-snippet-overlay (&optional point)
 439   "Get the most proper overlay which is belongs to a snippet."
 440   (let ((point (or point (point)))
 441         (snippet-overlay nil))
 442     (dolist (overlay (overlays-at point))
 443       (when (overlay-get overlay 'yas/snippet)
 444         (if (null snippet-overlay)
 445             (setq snippet-overlay overlay)
 446           (when (> (yas/snippet-id (overlay-get overlay 'yas/snippet))
 447                    (yas/snippet-id (overlay-get snippet-overlay 'yas/snippet)))
 448             (setq snippet-overlay overlay)))))
 449     snippet-overlay))
 450
 451 (defun yas/snippet-of-current-keymap (&optional point)
 452   "Get the snippet holding the snippet keymap under POINT."
 453   (let ((point (or point (point)))
 454         (keymap-snippet nil)
 455         (snippet nil))
 456     (dolist (overlay (overlays-at point))
 457       (setq snippet (overlay-get overlay 'yas/snippet-reference))
 458       (when snippet
 459         (if (null keymap-snippet)
 460             (setq keymap-snippet snippet)
 461           (when (> (yas/snippet-id snippet)
 462                    (yas/snippet-id keymap-snippet))
 463             (setq keymap-snippet snippet)))))
 464     keymap-snippet))
 465
 466 (defun yas/current-overlay-for-navigation ()
 467   "Get current overlay for navigation. Might be overlay at current or previous point."
 468   (let ((overlay1 (yas/current-snippet-overlay))
 469         (overlay2 (if (bobp)
 470                       nil
 471                     (yas/current-snippet-overlay (- (point) 1)))))
 472     (if (null overlay1)
 473         overlay2
 474       (if (or (null overlay2)
 475               (eq (overlay-get overlay1 'yas/snippet)
 476                   (overlay-get overlay2 'yas/snippet)))
 477           overlay1
 478         (if (> (yas/snippet-id (overlay-get overlay2 'yas/snippet))
 479                (yas/snippet-id (overlay-get overlay1 'yas/snippet)))
 480             overlay2
 481           overlay1)))))
 482
 483 (defun yas/navigate-group (group next?)
 484   "Go to next of previous field group. Exit snippet if none."
 485   (let ((target (if next?
 486                     (yas/group-next group)
 487                   (yas/group-prev group))))
 488     (if target
 489         (goto-char (overlay-start
 490                     (yas/field-overlay
 491                      (yas/group-primary-field target))))
 492       (yas/exit-snippet (yas/group-snippet group)))))
 493
 494 (defun yas/parse-template ()
 495   "Parse the template in the current buffer.
 496 If the buffer contains a line of \"# --\" then the contents
 497 above this line are ignored. Variables can be set above this
 498 line through the syntax:
 499
 500 #name : value
 501
 502 Currently only the \"name\" variable is recognized. Here's
 503 an example:
 504
 505 #name: #include \"...\"
 506 # --
 507 #include \"$1\""
 508   (goto-char (point-min))
 509   (let (template name bound)
 510     (if (re-search-forward "^# --\n" nil t)
 511         (progn (setq template
 512                      (buffer-substring-no-properties (point)
 513                                                      (point-max)))
 514                (setq bound (point))
 515                (goto-char (point-min))
 516                (while (re-search-forward "^#\\([^ ]+\\) *: *\\(.*\\)$" bound t)
 517                  (when (string= "name" (match-string-no-properties 1))
 518                    (setq name (match-string-no-properties 2)))))
 519       (setq template
 520             (buffer-substring-no-properties (point-min) (point-max))))
 521     (list template name)))
 522
 523 (defun yas/directory-files (directory file?)
 524   "Return directory files or subdirectories in full path."
 525   (remove-if (lambda (file)
 526                (and (not (string-match "/\\.[^/]*$" file))
 527                     (if file?
 528                         (not (file-directory-p file))
 529                       (file-directory-p file))))
 530              (directory-files directory t)))
 531
 532 (defun yas/make-menu-binding (template)
 533   (lexical-let ((template template))
 534     (lambda ()
 535       (interactive)
 536       (yas/expand-snippet (point)
 537                           (point)
 538                           template))))
 539
 540 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 541 ;; User level functions
 542 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 543 (defun yas/about ()
 544   (interactive)
 545   (message (concat "yasnippet (version "
 546                    yas/version
 547                    ") -- pluskid <pluskid@gmail.com>")))
 548 (defun yas/initialize ()
 549   "Do necessary initialization."
 550   (global-set-key yas/trigger-key 'yas/expand)
 551   (when yas/use-menu
 552     (define-key-after global-map
 553       [menu-bar yasnippet]
 554       (cons "YASnippet" yas/menu-keymap)
 555       'buffer)))
 556
 557 (defun yas/define (mode key template &optional name)
 558   "Define a snippet. Expanding KEY into TEMPLATE.
 559 NAME is a description to this template. Also update
 560 the menu if `yas/use-menu' is `t'."
 561   (let ((template (yas/make-template template (or name key))))
 562     (puthash key
 563              template
 564              (yas/snippet-table mode))
 565     (when yas/use-menu
 566       (let ((keymap (yas/menu-keymap-for-mode mode)))
 567         (define-key yas/menu-keymap (vector mode)
 568           `(menu-item ,(symbol-name mode) ,keymap))
 569         (define-key keymap (vector (make-symbol key))
 570           `(menu-item ,(yas/template-name template)
 571                       ,(yas/make-menu-binding (yas/template-content template))
 572                       :keys ,(concat key yas/trigger-symbol)))))))
 573
 574 (defun yas/expand ()
 575   "Expand a snippet. When a snippet is expanded, t is returned,
 576 otherwise, nil returned."
 577   (interactive)
 578   (multiple-value-bind (key start end) (yas/current-key)
 579     (let ((template (yas/template key (yas/current-snippet-table))))
 580       (if template
 581           (yas/expand-snippet start end (yas/template-content template))
 582         (when yas/trigger-fallback
 583           (call-interactively yas/trigger-fallback))))))
 584
 585 (defun yas/next-field-group ()
 586   "Navigate to next field group. If there's none, exit the snippet."
 587   (interactive)
 588   (let ((overlay (yas/current-overlay-for-navigation)))
 589     (if overlay
 590         (yas/navigate-group (overlay-get overlay 'yas/group) t)
 591       (let ((snippet (yas/snippet-of-current-keymap))
 592             (done nil))
 593         (if snippet
 594           (do* ((tabstops (yas/snippet-tabstops snippet) (cdr tabstops))
 595                 (tabstop (car tabstops) (car tabstops)))
 596               ((or (null tabstops)
 597                    done)
 598                (unless done (message "Not in a snippet field.")))
 599             (when (= (point)
 600                      (overlay-start
 601                       (yas/field-overlay
 602                        (yas/group-primary-field tabstop))))
 603               (setq done t)
 604               (yas/navigate-group tabstop t)))
 605           (message "Not in a snippet field."))))))
 606
 607 (defun yas/prev-field-group ()
 608   "Navigate to prev field group. If there's none, exit the snippet."
 609   (interactive)
 610   (let ((overlay (yas/current-overlay-for-navigation)))
 611     (if overlay
 612         (yas/navigate-group (overlay-get overlay 'yas/group) nil)
 613       (let ((snippet (yas/snippet-of-current-keymap))
 614             (done nil))
 615         (if snippet
 616           (do* ((tabstops (yas/snippet-tabstops snippet) (cdr tabstops))
 617                 (tabstop (car tabstops) (car tabstops)))
 618               ((or (null tabstops)
 619                    done)
 620                (unless done (message "Not in a snippet field.")))
 621             (when (= (point)
 622                      (overlay-start
 623                       (yas/field-overlay
 624                        (yas/group-primary-field tabstop))))
 625               (setq done t)
 626               (yas/navigate-group tabstop nil)))
 627           (message "Not in a snippet field."))))))
 628
 629 (defun yas/exit-snippet (snippet)
 630   "Goto exit-marker of SNIPPET and delete the snippet."
 631   (interactive)
 632   (goto-char (yas/snippet-exit-marker snippet))
 633   (delete-overlay (yas/snippet-overlay snippet))
 634   (dolist (group (yas/snippet-groups snippet))
 635     (dolist (field (yas/group-fields group))
 636       (delete-overlay (yas/field-overlay field)))))
 637
 638 (defun yas/load-directory (directory)
 639   "Load snippet definition from a directory hierarchy.
 640 Below the top-level directory, each directory is a mode
 641 name. And under each subdirectory, each file is a definition
 642 of a snippet. The file name is the trigger key and the
 643 content of the file is the template."
 644   (with-temp-buffer
 645     (dolist (mode (yas/directory-files directory nil))
 646       (let* ((mode-sym (intern (file-name-nondirectory mode)))
 647              (snippet-table (yas/snippet-table mode-sym))
 648              (keymap (if yas/use-menu
 649                          (yas/menu-keymap-for-mode mode-sym)
 650                        nil)))
 651         (dolist (key (yas/directory-files mode t))
 652           (when (file-readable-p key)
 653             (insert-file-contents key nil nil nil t)
 654             (multiple-value-bind
 655                 (key template name)
 656                 (cons (file-name-sans-extension
 657                         (file-name-nondirectory key))
 658                       (yas/parse-template))
 659               (puthash key
 660                        (yas/make-template
 661                         template
 662                         (or name key))
 663                        snippet-table)
 664               (when yas/use-menu
 665                 (define-key yas/menu-keymap (vector mode-sym)
 666                   `(menu-item ,(symbol-name mode-sym) ,keymap))
 667                 (define-key keymap (vector (make-symbol key))
 668                   `(menu-item ,(or name key)
 669                               ,(yas/make-menu-binding template)
 670                               :keys ,(concat key yas/trigger-symbol)))))))))))
 671
 672 (provide 'yasnippet)