emacs/lisp/progmodes/antlr-mode.el

;;; antlr-mode.el --- Major mode for ANTLR grammar files

;; Copyright (C) 1999-2000 Free Software Foundation, Inc.
;;
;; Author: Christoph.Wedler@sap.com
;; Version: $Id: antlr-mode.el,v 1.2 1999/12/16 19:30:34 wedler Exp $
;; X-URL: http://www.fmi.uni-passau.de/~wedler/antlr-mode/

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Major mode for editing ANTLR grammar files, i.e., files ending with `.g'.
;; ANTLR is ANother Tool for Language Recognition (an excellent alternative to
;; lex/yacc), see <http://www.ANTLR.org> and <news:comp.compilers.tools.pccts>.

;; Variable `antlr-language' is set according to the language in actions and
;; semantic predicates of the grammar (see ANTLR's file option "language").
;; The supported languages are "Java" (java-mode) and "Cpp" (c++-mode).  This
;; package uses features of the Emacs package cc-mode.

;; This package provides the following features:
;;  * Indentation for the current line (TAB) and selected region (C-M-\).
;;  * Syntax coloring (via font-lock) with language dependent coloring.
;;  * Support for imenu/speedbar: menu "Index" (Parser, Lexer, TreeParser).
;;  * Direct move to previous/next rule, beginning/end of rule body etc.

;; INDENTATION.  This package supports ANTLR's (intended) indentation style
;; which is based on a simple paren/brace/bracket depth-level calculation, see
;; `antlr-indent-line'.  The indentation engine of cc-mode is only used inside
;; block comments (it is not easy to use it for actions, esp if they come early
;; in the rule body).  By default, this package uses TABs for a basic offset of
;; 4 to be consistent to both ANTLR's conventions (TABs usage) and the
;; `c-indentation-style' "java" which sets `c-basic-offset' to 4, see
;; `antlr-tab-offset-alist'.  You might want to set this variable to nil.

;; SYNTAX COLORING comes in three phases.  First, comments and strings are
;; highlighted.  Second, the grammar code is highlighted according to
;; `antlr-font-lock-additional-keywords' (rule refs: blue, token refs: brown,
;; definition: ditto+bold).  Third, actions, semantic predicates and arguments
;; are highlighted according to the usual font-lock keywords of
;; `antlr-language', see also `antlr-font-lock-maximum-decoration'.  We define
;; special font-lock faces for the grammar code to allow you to distinguish
;; ANTLR keywords from Java/C++ keywords.

;; Bug fixes, bug reports, improvements, and suggestions are strongly
;; appreciated.  Please check the newest version first:
;;   http://www.fmi.uni-passau.de/~wedler/antlr-mode/changes.html

;;; Installation:

;; This file requires Emacs-20.3, XEmacs-20.4 or higher.

;; If antlr-mode is not part of your distribution, put this file into your
;; load-path and the following into your ~/.emacs:
;;   (autoload 'antlr-mode "antlr-mode" nil t)
;;   (setq auto-mode-alist (cons '("\\.g\\'" . antlr-mode) auto-mode-alist))
;;   (add-hook 'speedbar-load-hook  ; would be too late in antlr-mode.el
;;	       (lambda () (speedbar-add-supported-extension ".g")))

;; If you edit ANTLR's source files, you might also want to use
;;   (autoload 'antlr-set-tabs "antlr-mode")
;;   (add-hook 'java-mode-hook 'antlr-set-tabs)

;; I strongly recommend to use font-lock with a support mode like fast-lock,
;; lazy-lock or better jit-lock (Emacs-21.1+) / lazy-shot (XEmacs).

;; To customize, use `M-x customize-group RET antlr RET' or the custom browser
;; (Emacs->Programming->Languages->Antlr).

;;; Code:

(provide 'antlr-mode)
(eval-when-compile (require 'cc-mode))	; shut up most warnings
(require 'easymenu)			; Emacs
(eval-when-compile			; optional libraries
  (defvar outline-level) (defvar imenu-use-markers))
(eval-when-compile			; Emacs: cl, XEmacs vars
  (require 'cl))
(eval-when-compile			; XEmacs: Emacs vars
  (defvar inhibit-point-motion-hooks) (defvar deactivate-mark))

(eval-and-compile
  (if (string-match "XEmacs" emacs-version)
      (defalias 'antlr-scan-sexps 'scan-sexps)
    (defalias 'antlr-scan-sexps 'antlr-scan-sexps-internal))
  (if (and (fboundp 'buffer-syntactic-context)
	   (fboundp 'buffer-syntactic-context-depth))
      (progn
	(defalias 'antlr-invalidate-context-cache 'antlr-xemacs-bug-workaround)
	(defalias 'antlr-syntactic-context 'antlr-fast-syntactic-context))
    (defalias 'antlr-invalidate-context-cache 'ignore)
    (defalias 'antlr-syntactic-context 'antlr-slow-syntactic-context)))



;;;;##########################################################################
;;;;  Variables
;;;;##########################################################################


(defgroup antlr nil
  "Major mode for ANTLR grammar files."
  :group 'languages
  :link '(emacs-commentary-link "antlr-mode.el")
  :link '(url-link "http://www.fmi.uni-passau.de/~wedler/antlr-mode/")
  :prefix "antlr-")

(defconst antlr-version "1.3"
  "ANTLR major mode version number.")


;;;===========================================================================
;;;  Controlling ANTLR's code generator (language option)
;;;===========================================================================

(defvar antlr-language nil
  "Major mode corresponding to ANTLR's \"language\" option.
Set via `antlr-language-alist'.  The only useful place to change this
buffer-local variable yourself is in `antlr-mode-hook' or in the \"local
variable list\" near the end of the file, see
`enable-local-variables'.")

(defcustom antlr-language-alist
  '((java-mode "Java" nil "Java")
    (c++-mode "C++" "Cpp"))
  "List of ANTLR's supported languages.
Each element in this list looks like
  (MAJOR-MODE MODELINE-STRING OPTION-VALUE...)

MAJOR-MODE, the major mode of the code in the grammar's actions, is the
value of `antlr-language' if the first regexp group matched by REGEXP in
`antlr-language-limit-n-regexp' is one of the OPTION-VALUEs.  An
OPTION-VALUE of nil denotes the fallback element.  MODELINE-STRING is
also displayed in the modeline next to \"Antlr\"."
  :group 'antlr
  :type '(repeat (group :value (java-mode "")
			(function :tag "Major mode")
			(string :tag "Modeline string")
			(repeat :tag "ANTLR language option" :inline t
				(choice (const :tag "Default" nil)
					string )))))

(defcustom antlr-language-limit-n-regexp
  '(3000 . "language[ \t]*=[ \t]*\"\\([A-Z][A-Za-z_]*\\)\"")
  "Used to set a reasonable value for `antlr-language'.
Looks like (LIMIT . REGEXP).  Search for REGEXP from the beginning of
the buffer to LIMIT to set the language according to
`antlr-language-alist'."
  :group 'antlr
  :type '(cons (choice :tag "Limit" (const :tag "No" nil) (integer :value 0))
	       regexp))


;;;===========================================================================
;;;  Indent/Tabs
;;;===========================================================================

(defcustom antlr-tiny-action-length 3
  "Maximal number of characters in actions never to hide.
See command `antlr-hide-actions'."
  :group 'antlr
  :type 'integer)

(defcustom antlr-indent-comment 'tab
  "*Non-nil, if the indentation should touch lines in block comments.
If nil, no continuation line of a block comment is changed.  If t, they
are changed according to `c-indentation-line'.  When not nil and not t,
they are only changed by \\[antlr-indent-command]."
  :group 'antlr
  :type '(radio (const :tag "No" nil)
		(const :tag "Always" t)
		(sexp :tag "With TAB" :format "%t" :value tab)))

(defcustom antlr-tab-offset-alist
  '((antlr-mode nil 4 t)
    (java-mode "antlr" 4 t))
  "Alist to determine whether to use ANTLR's convention for TABs.
Each element looks like (MAJOR-MODE REGEXP TAB-WIDTH INDENT-TABS-MODE).
The first element whose MAJOR-MODE is nil or equal to `major-mode' and
whose REGEXP is nil or matches `buffer-file-name' is used to set
`tab-width' and `indent-tabs-mode'.  This is useful to support both
ANTLR's and Java's indentation styles.  Used by `antlr-set-tabs'."
  :group 'antlr
  :type '(repeat (group :value (antlr-mode nil 8 nil)
			(choice (const :tag "All" nil)
				(function :tag "Major mode"))
			(choice (const :tag "All" nil) regexp)
			(integer :tag "Tab width")
			(boolean :tag "Indent-tabs-mode"))))

(defvar antlr-indent-item-regexp
  "[]}):;|&]\\|default[ \t]*:\\|case[ \t]+\\('\\\\?.'\\|[0-9]+\\|[A-Za-z_][A-Za-z_0-9]*\\)[ \t]*:" ; & is local ANTLR extension
  "Regexp matching lines which should be indented by one TAB less.
See command \\[antlr-indent-command].")


;;;===========================================================================
;;;  Menu
;;;===========================================================================

(defcustom antlr-imenu-name t
  "*Non-nil, if a \"Index\" menu should be added to the menubar.
If it is a string, it is used instead \"Index\".  Requires package
imenu."
  :group 'antlr
  :type '(choice (const :tag "No menu" nil)
		 (const :tag "Index menu" t)
		 (string :tag "Other menu name")))

(defvar antlr-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\t" 'antlr-indent-command)
    (define-key map "\e\C-a" 'antlr-beginning-of-rule)
    (define-key map "\e\C-e" 'antlr-end-of-rule)
    (define-key map "\C-c\C-a" 'antlr-beginning-of-body)
    (define-key map "\C-c\C-e" 'antlr-end-of-body)
    (define-key map "\C-c\C-f" 'c-forward-into-nomenclature)
    (define-key map "\C-c\C-b" 'c-backward-into-nomenclature)
    (define-key map "\C-c\C-c" 'comment-region)
    (define-key map "\C-c\C-v" 'antlr-hide-actions)
    ;; I'm too lazy to define my own:
    (define-key map "\ea" 'c-beginning-of-statement)
    (define-key map "\ee" 'c-end-of-statement)
    map)
  "Keymap used in `antlr-mode' buffers.")

(easy-menu-define antlr-mode-menu
		  antlr-mode-map
		  "Major mode menu."
		  '("Antlr"
		    ["Indent Line" antlr-indent-command
		     :active (not buffer-read-only)]
		    ["Indent for Comment" indent-for-comment
		     :active (not buffer-read-only)]
		    ["Comment Out Region" comment-region
		     :active (and (not buffer-read-only)
				  (c-region-is-active-p))]
		    ["Uncomment Region"
		     (comment-region (region-beginning) (region-end) '(4))
		     :active (and (not buffer-read-only)
				  (c-region-is-active-p))]
		    "---"
		    ["Backward Rule" antlr-beginning-of-rule t]
		    ["Forward Rule" antlr-end-of-rule t]
		    ["Start of Rule Body" antlr-beginning-of-body
		     :active (antlr-inside-rule-p)]
		    ["End of Rule Body" antlr-end-of-body
		     :active (antlr-inside-rule-p)]
		    "---"
		    ["Backward Statement" c-beginning-of-statement t]
		    ["Forward Statement" c-end-of-statement t]
		    ["Backward Into Nomencl." c-backward-into-nomenclature t]
		    ["Forward Into Nomencl." c-forward-into-nomenclature t]
		    "---"
		    ["Hide Actions (incl. Args)" antlr-hide-actions t]
		    ["Hide Actions (excl. Args)" (antlr-hide-actions 2) t]
		    ["Unhide All Actions" (antlr-hide-actions 0) t]))


;;;===========================================================================
;;;  font-lock
;;;===========================================================================

(defcustom antlr-font-lock-maximum-decoration 'inherit
  "*The maximum decoration level for fontifying actions.
Value `none' means, do not fontify actions, just normal grammar code
according to `antlr-font-lock-additional-keywords'.  Value `inherit'
means, use value of `font-lock-maximum-decoration'.  Any other value is
interpreted as in `font-lock-maximum-decoration' with no level-0
fontification, see `antlr-font-lock-keywords-alist'.

While calculating the decoration level for actions, `major-mode' is
bound to `antlr-language'.  For example, with value
  ((java-mode . 2) (c++-mode . 0))
Java actions are fontified with level 2 and C++ actions are not
fontified at all."
  :type '(choice (const :tag "none" none)
		 (const :tag "inherit" inherit)
		 (const :tag "default" nil)
		 (const :tag "maximum" t)
		 (integer :tag "level" 1)
		 (repeat :menu-tag "mode specific" :tag "mode specific"
			 :value ((t . t))
			 (cons :tag "Instance"
			       (radio :tag "Mode"
				      (const :tag "all" t)
				      (symbol :tag "name"))
			       (radio :tag "Decoration"
				      (const :tag "default" nil)
				      (const :tag "maximum" t)
				      (integer :tag "level" 1))))))

(defvar antlr-font-lock-keywords-alist
  '((java-mode
     (list)				; nil won't work (would use level-3)
     java-font-lock-keywords-1 java-font-lock-keywords-2
     java-font-lock-keywords-3)
    (c++-mode
     (list)				; nil won't work (would use level-3)
     c++-font-lock-keywords-1 c++-font-lock-keywords-2
     c++-font-lock-keywords-3))
  "List of font-lock keywords for actions in the grammar.
Each element in this list looks like
  (MAJOR-MODE KEYWORD...)

If `antlr-language' is equal to MAJOR-MODE, the KEYWORDs are the
font-lock keywords according to `font-lock-defaults' used for the code
in the grammar's actions and semantic predicates, see
`antlr-font-lock-maximum-decoration'.")

(defvar antlr-font-lock-keyword-face 'antlr-font-lock-keyword-face)
(defface antlr-font-lock-keyword-face
  '((((class color) (background light)) (:foreground "black" :bold t)))
  "ANTLR keywords."
  :group 'antlr)

(defvar antlr-font-lock-ruledef-face 'antlr-font-lock-ruledef-face)
(defface antlr-font-lock-ruledef-face
  '((((class color) (background light)) (:foreground "blue" :bold t)))
  "ANTLR rule references (definition)."
  :group 'antlr)

(defvar antlr-font-lock-tokendef-face 'antlr-font-lock-tokendef-face)
(defface antlr-font-lock-tokendef-face
  '((((class color) (background light)) (:foreground "brown3" :bold t)))
  "ANTLR token references (definition)."
  :group 'antlr)

(defvar antlr-font-lock-ruleref-face 'antlr-font-lock-ruleref-face)
(defface antlr-font-lock-ruleref-face
  '((((class color) (background light)) (:foreground "blue4")))
  "ANTLR rule references (usage)."
  :group 'antlr)

(defvar antlr-font-lock-tokenref-face 'antlr-font-lock-tokenref-face)
(defface antlr-font-lock-tokenref-face
  '((((class color) (background light)) (:foreground "brown4")))
  "ANTLR token references (usage)."
  :group 'antlr)

(defvar antlr-font-lock-literal-face 'antlr-font-lock-literal-face)
(defface antlr-font-lock-literal-face
  '((((class color) (background light)) (:foreground "brown4" :bold t)))
  "ANTLR literal tokens consisting merely of letter-like characters."
  :group 'antlr)

(defvar antlr-font-lock-additional-keywords
  `((antlr-invalidate-context-cache)
    ("\\$setType[ \t]*(\\([A-Z\300-\326\330-\337]\\sw*\\))"
     (1 antlr-font-lock-tokendef-face))
    ("\\$\\sw+" (0 font-lock-keyword-face))
    ;; the tokens are already fontified as string/docstrings:
    (,(lambda (limit)
	(antlr-re-search-forward "\"\\(\\sw\\(\\sw\\|-\\)*\\)\"" limit))
     (1 antlr-font-lock-literal-face t)
     ,@(and (string-match "XEmacs" emacs-version)
	    '((0 nil))))		; XEmacs bug workaround
    (,(lambda (limit)
	(antlr-re-search-forward
	 "^\\(class\\)[ \t]+\\([A-Z\300-\326\330-\337]\\sw*\\)[ \t]+\\(extends\\)[ \t]+\\([A-Z\300-\326\330-\337]\\sw*\\)[ \t]*;" limit))
     (1 antlr-font-lock-keyword-face)
     (2 antlr-font-lock-ruledef-face)
     (3 antlr-font-lock-keyword-face)
     (4 (if (member (match-string 4) '("Lexer" "Parser" "TreeParser"))
	    'antlr-font-lock-keyword-face
	  'font-lock-type-face)))
    (,(lambda (limit)
	(antlr-re-search-forward
	 "\\<\\(header\\|options\\|tokens\\|exception\\|catch\\|returns\\)\\>"
	 limit))
     (1 antlr-font-lock-keyword-face))
    (,(lambda (limit)
	(antlr-re-search-forward
	 "^\\(private\\|public\\|protected\\)\\>\\([ \t]+\\(\\sw+\\)\\)?"
	 limit))
     (1 font-lock-type-face)		; not XEmacs' java level-3 fruit salad
     (3 (if (antlr-upcase-p (char-after (match-beginning 3)))
	    'antlr-font-lock-tokendef-face
	  'antlr-font-lock-ruledef-face) nil t))
    (,(lambda (limit)
	(antlr-re-search-forward "^\\sw+" limit))
     (0 (if (antlr-upcase-p (char-after (match-beginning 0)))
	    'antlr-font-lock-tokendef-face
	  'antlr-font-lock-ruledef-face) nil t))
    (,(lambda (limit)
	;; not only before a rule ref, also before a literal
	(antlr-re-search-forward "\\<\\(\\sw+\\)[ \t]*:" limit))
     (1 font-lock-variable-name-face))
    (,(lambda (limit)
	(antlr-re-search-forward "\\<\\(\\sw+[ \t]*=[ \t]*\\)?\\(\\sw+[ \t]*:[ \t]*\\)?\\(\\sw+\\)" limit))
     ;;(1 antlr-font-lock-default-face nil t) ; fool java-font-lock-keywords
     (3 (if (antlr-upcase-p (char-after (match-beginning 3)))
	    'antlr-font-lock-tokenref-face
	  'antlr-font-lock-ruleref-face))))
  "Font-lock keywords for ANTLR's normal grammar code.
See `antlr-font-lock-keywords-alist' for the keywords of actions.")

(defvar antlr-font-lock-defaults
  '(antlr-font-lock-keywords
    nil nil ((?_ . "w") (?\( . ".") (?\) . ".")) beginning-of-defun)
  "Font-lock defaults used for ANTLR syntax coloring.
The SYNTAX-ALIST element is also used to initialize
`antlr-action-syntax-table'.")


;;;===========================================================================
;;;  Internal variables
;;;===========================================================================

(defvar antlr-mode-hook nil
  "Hook called by `antlr-mode'.")

;; used for "in Java/C++ code" = syntactic-depth>0
(defvar antlr-action-syntax-table nil
  "Syntax table used for ANTLR action parsing.
Initialized by `java-mode-syntax-table', i.e., the syntax table used for
grammar files, changed by SYNTAX-ALIST in `antlr-font-lock-defaults'.
This table should be selected if you use `buffer-syntactic-context' and
`buffer-syntactic-context-depth' in order not to confuse their
context_cache.")

(defvar antlr-mode-abbrev-table nil
  "Abbreviation table used in `antlr-mode' buffers.")
(define-abbrev-table 'antlr-mode-abbrev-table ())



;;;;##########################################################################
;;;;  The Code
;;;;##########################################################################


;;;===========================================================================
;;;  Syntax functions -- Emacs vs XEmacs dependent
;;;===========================================================================

;; From help.el (XEmacs-21.1)
(defmacro antlr-with-syntax-table (syntab &rest body)
  `(let ((stab (syntax-table)))
     (unwind-protect
	 (progn (set-syntax-table (copy-syntax-table ,syntab)) ,@body)
       (set-syntax-table stab))))
(put 'antlr-with-syntax-table 'lisp-indent-function 1)
(put 'antlr-with-syntax-table 'edebug-form-spec '(form body))

(defun antlr-scan-sexps-internal (from count &optional dummy no-error)
;; checkdoc-params: (from count dummy)
  "Like `scan-sexps' but with additional arguments.
When optional arg NO-ERROR is non-nil, `scan-sexps' will return nil
instead of signaling an error."
  (if no-error
      (condition-case nil
	  (scan-sexps from count)
	(t nil))
    (scan-sexps from count)))

(defun antlr-xemacs-bug-workaround (&rest dummies)
;; checkdoc-params: (dummies)
  "Invalidate context_cache for syntactical context information."
  ;; XEmacs bug workaround
  (save-excursion
    (set-buffer (get-buffer-create " ANTLR XEmacs bug workaround"))
    (buffer-syntactic-context-depth))
  nil)

(defun antlr-fast-syntactic-context ()
  "Return some syntactic context information.
Return `string' if point is within a string, `block-comment' or
`comment' is point is within a comment or the depth within all
parenthesis-syntax delimiters at point otherwise.
WARNING: this may alter `match-data'."
  (or (buffer-syntactic-context) (buffer-syntactic-context-depth)))

(defun antlr-slow-syntactic-context ()
  "Return some syntactic context information.
Return `string' if point is within a string, `block-comment' or
`comment' is point is within a comment or the depth within all
parenthesis-syntax delimiters at point otherwise.
WARNING: this may alter `match-data'."
  (let ((orig (point)))
    (beginning-of-defun)
    (let ((state (parse-partial-sexp (point) orig)))
      (goto-char orig)
      (cond ((nth 3 state) 'string)
	    ((nth 4 state) 'comment)	; block-comment? -- we don't care
	    (t (car state))))))


;;;===========================================================================
;;;  Misc functions
;;;===========================================================================

(defun antlr-upcase-p (char)
  "Non-nil, if CHAR is an uppercase character (if CHAR was a char)."
  ;; in XEmacs, upcase only works for ASCII
  (or (and (<= ?A char) (<= char ?Z))
      (and (<= ?\300 char) (<= char ?\337)))) ; ?\327 is no letter

(defun antlr-re-search-forward (regexp bound)
  "Search forward from point for regular expression REGEXP.
Set point to the end of the occurrence found, and return point.  Return
nil if no occurrence was found.  Do not search within comments, strings
and actions/semantic predicates.  BOUND bounds the search; it is a
buffer position.  See also the functions `match-beginning', `match-end'
and `replace-match'."
  ;; WARNING: Should only be used with `antlr-action-syntax-table'!
  (let ((continue t))
    (while (and (re-search-forward regexp bound 'limit)
		(save-match-data
		  (if (eq (antlr-syntactic-context) 0)
		      (setq continue nil)
		    t))))
    (if continue nil (point))))

(defun antlr-search-forward (string)
  "Search forward from point for STRING.
Set point to the end of the occurrence found, and return point.  Return
nil if no occurrence was found.  Do not search within comments, strings
and actions/semantic predicates."
  ;; WARNING: Should only be used with `antlr-action-syntax-table'!
  (let ((continue t))
    (while (and (search-forward string nil 'limit)
		(if (eq (antlr-syntactic-context) 0) (setq continue nil) t)))
    (if continue nil (point))))

(defun antlr-search-backward (string)
  "Search backward from point for STRING.
Set point to the beginning of the occurrence found, and return point.
Return nil if no occurrence was found.  Do not search within comments,
strings and actions/semantic predicates."
  ;; WARNING: Should only be used with `antlr-action-syntax-table'!
  (let ((continue t))
    (while (and (search-backward string nil 'limit)
		(if (eq (antlr-syntactic-context) 0) (setq continue nil) t)))
    (if continue nil (point))))

(defsubst antlr-skip-sexps (count)
  "Skip the next COUNT balanced expressions and the comments after it.
Return position before the comments after the last expression."
  (goto-char (or (antlr-scan-sexps (point) count nil t) (point-max)))
  (prog1 (point)
    (c-forward-syntactic-ws)))


;;;===========================================================================
;;;  font-lock
;;;===========================================================================

(defun antlr-font-lock-keywords ()
  "Return font-lock keywords for current buffer.
See `antlr-font-lock-additional-keywords', `antlr-language' and
`antlr-font-lock-maximum-decoration'."
  (if (eq antlr-font-lock-maximum-decoration 'none)
      antlr-font-lock-additional-keywords
    (append antlr-font-lock-additional-keywords
	    (eval (let ((major-mode antlr-language)) ; dynamic
			(font-lock-choose-keywords
			 (cdr (assq antlr-language
				    antlr-font-lock-keywords-alist))
			 (if (eq antlr-font-lock-maximum-decoration 'inherit)
			     font-lock-maximum-decoration
			   antlr-font-lock-maximum-decoration)))))))


;;;===========================================================================
;;;  imenu support
;;;===========================================================================

(defun antlr-imenu-create-index-function ()
  "Return imenu index-alist for ANTLR grammar files."
  (let ((items nil)
	(lexer nil)
	(parser nil)
	(treeparser nil)
	(misc nil)
	(classes nil)
	(semi (point-max)))
    ;; Using `imenu-progress-message' would require imenu for compilation --
    ;; nobody is missing these messages...
    (antlr-with-syntax-table antlr-action-syntax-table
      ;; We stick to the imenu standard and search backwards, although I don't
      ;; think this is right.  It is slower and more likely not to work during
      ;; editing (you are more likely to add functions to the end of the file).
      (while semi
	(goto-char semi)
	(if (setq semi (antlr-search-backward ";"))
	    (progn (forward-char) (antlr-skip-exception-part t))
	  (antlr-skip-file-prelude t))
	(if (looking-at "{") (antlr-skip-sexps 1))
	(if (looking-at "class[ \t]+\\([A-Z\300-\326\330-\337]\\sw*\\)[ \t]+extends[ \t]+\\([A-Z\300-\326\330-\337]\\sw*\\)[ \t]*;")
	    (progn
	      (push (cons (match-string 1)
			  (if imenu-use-markers
			      (copy-marker (match-beginning 1))
			    (match-beginning 1)))
		    classes)
	      (if items
		  (let ((super (match-string 2)))
		    (cond ((string-equal super "Parser")
			   (setq parser (nconc items parser)))
			  ((string-equal super "Lexer")
			   (setq lexer (nconc items lexer)))
			  ((string-equal super "TreeParser")
			   (setq treeparser (nconc items treeparser)))
			  (t
			   (setq misc (nconc items misc))))
		    (setq items nil))))
	  (if (looking-at "p\\(ublic\\|rotected\\|rivate\\)")
	      (antlr-skip-sexps 1))
	  (when (looking-at "\\sw+")
	    (push (cons (match-string 0)
			(if imenu-use-markers
			    (copy-marker (match-beginning 0))
			  (match-beginning 0)))
		  items)))))
    (or items				; outside any class
	(prog1 (setq items misc) (setq misc nil))
	(prog1 (setq items parser) (setq parser nil))
	(prog1 (setq items lexer) (setq lexer nil))
	(prog1 (setq items treeparser) (setq treeparser nil)))
    (if misc (push (cons "Miscellaneous" misc) items))
    (if treeparser (push (cons "TreeParser" treeparser) items))
    (if lexer (push (cons "Lexer" lexer) items))
    (if parser (push (cons "Parser" parser) items))
    (if classes (cons (cons "Classes" classes) items) items)))


;;;===========================================================================
;;;  Parse grammar files (internal functions)
;;;===========================================================================

(defun antlr-skip-exception-part (skip-comment)
  "Skip exception part of current rule, i.e., everything after `;'.
This also includes the options and tokens part of a grammar class
header.  If SKIP-COMMENT is non-nil, also skip the comment after that
part."
  (let ((pos (point))
	(class nil))
    (c-forward-syntactic-ws)
    (while (looking-at "options\\>\\|tokens\\>")
      (setq class t)
      (setq pos (antlr-skip-sexps 2)))
    (if class
	;; Problem: an action only belongs to a class def, not a normal rule.
	;; But checking the current rule type is too expensive => only expect
	;; an action if we have found an option or tokens part.
	(if (looking-at "{") (setq pos (antlr-skip-sexps 1)))
      (while (looking-at "exception\\>")
	(setq pos (antlr-skip-sexps 1))
	(if (looking-at "\\[") (setq pos (antlr-skip-sexps 1)))
	(while (looking-at "catch\\>")
	  (setq pos (antlr-skip-sexps 3)))))
    (or skip-comment (goto-char pos))))

(defun antlr-skip-file-prelude (skip-comment)
  "Skip the file prelude: the header and file options.
If SKIP-COMMENT is non-nil, also skip the comment after that part."
  (let* ((pos (point))
	 (pos0 pos))
    (c-forward-syntactic-ws)
    (if skip-comment (setq pos0 (point)))
    (if (looking-at "header\\>") (setq pos (antlr-skip-sexps 2)))
    (if (looking-at "options\\>") (setq pos (antlr-skip-sexps 2)))
    (or skip-comment (goto-char pos))
    pos0))

(defun antlr-next-rule (arg skip-comment)
  "Move forward to next end of rule.  Do it ARG many times.
A grammar class header and the file prelude are also considered as a
rule.  Negative argument ARG means move back to ARGth preceding end of
rule.  The behavior is not defined when ARG is zero.  If SKIP-COMMENT
is non-nil, move to beginning of the rule."
  ;; WARNING: Should only be used with `antlr-action-syntax-table'!
  ;; PRE: ARG<>0
  (let ((pos (point))
	(beg (point)))
    ;; first look whether point is in exception part
    (if (antlr-search-backward ";")
	(progn
	  (setq beg (point))
	  (forward-char)
	  (antlr-skip-exception-part skip-comment))
      (antlr-skip-file-prelude skip-comment))
    (if (< arg 0)
	(unless (and (< (point) pos) (zerop (incf arg)))
	  ;; if we have moved backward, we already moved one defun backward
	  (goto-char beg)		; rewind (to ";" / point)
	  (while (and arg (<= (incf arg) 0))
	    (if (antlr-search-backward ";")
		(setq beg (point))
	      (when (>= arg -1)
		;; try file prelude:
		(setq pos (antlr-skip-file-prelude skip-comment))
		(if (zerop arg)
		    (if (>= (point) beg)
			(goto-char (if (>= pos beg) (point-min) pos)))
		  (goto-char (if (or (>= (point) beg) (= (point) pos))
				 (point-min) pos))))
	      (setq arg nil)))
	  (when arg			; always found a ";"
	    (forward-char)
	    (antlr-skip-exception-part skip-comment)))
      (if (<= (point) pos)		; moved backward?
	  (goto-char pos)		; rewind
	(decf arg))			; already moved one defun forward
      (unless (zerop arg)
	(while (>= (decf arg) 0)
	  (antlr-search-forward ";"))
	(antlr-skip-exception-part skip-comment)))))

(defun antlr-outside-rule-p ()
  "Non-nil if point is outside a grammar rule.
Move to the beginning of the current rule if point is inside a rule."
  ;; WARNING: Should only be used with `antlr-action-syntax-table'!
  (let ((pos (point)))
    (antlr-next-rule -1 nil)
    (let ((between (or (bobp) (< (point) pos))))
      (c-forward-syntactic-ws)
      (and between (> (point) pos) (goto-char pos)))))


;;;===========================================================================
;;;  Parse grammar files (commands)
;;;===========================================================================
;; No (interactive "_") in Emacs... use `zmacs-region-stays'.

(defun antlr-inside-rule-p ()
  "Non-nil if point is inside a grammar rule.
A grammar class header and the file prelude are also considered as a
rule."
  (save-excursion
    (antlr-with-syntax-table antlr-action-syntax-table
      (not (antlr-outside-rule-p)))))

(defun antlr-end-of-rule (&optional arg)
  "Move forward to next end of rule.  Do it ARG [default: 1] many times.
A grammar class header and the file prelude are also considered as a
rule.  Negative argument ARG means move back to ARGth preceding end of
rule.  If ARG is zero, run `antlr-end-of-body'."
  (interactive "p")
  (if (zerop arg)
      (antlr-end-of-body)
    (antlr-with-syntax-table antlr-action-syntax-table
      (antlr-next-rule arg nil))
    (setq zmacs-region-stays t)))

(defun antlr-beginning-of-rule (&optional arg)
  "Move backward to preceding beginning of rule.  Do it ARG many times.
A grammar class header and the file prelude are also considered as a
rule.  Negative argument ARG means move forward to ARGth next beginning
of rule.  If ARG is zero, run `antlr-beginning-of-body'."
  (interactive "p")
  (if (zerop arg)
      (antlr-beginning-of-body)
    (antlr-with-syntax-table antlr-action-syntax-table
      (antlr-next-rule (- arg) t))
    (setq zmacs-region-stays t)))

(defun antlr-end-of-body (&optional msg)
  "Move to position after the `;' of the current rule.
A grammar class header is also considered as a rule.  With optional
prefix arg MSG, move to `:'."
  (interactive)
  (antlr-with-syntax-table antlr-action-syntax-table
    (let ((orig (point)))
      (if (antlr-outside-rule-p)
	  (error "Outside an ANTLR rule"))
      (let ((bor (point)))
	(when (< (antlr-skip-file-prelude t) (point))
	  ;; Yes, we are in the file prelude
	  (goto-char orig)
	  (error (or msg "The file prelude is without `;'")))
	(antlr-search-forward ";")
	(when msg
	  (when (< (point)
		   (progn (goto-char bor)
			  (or (antlr-search-forward ":") (point-max))))
	    (goto-char orig)
	    (error msg))
	  (c-forward-syntactic-ws)))))
  (setq zmacs-region-stays t))

(defun antlr-beginning-of-body ()
  "Move to the first element after the `:' of the current rule."
  (interactive)
  (antlr-end-of-body "Class headers and the file prelude are without `:'"))


;;;===========================================================================
;;;  Literal normalization, Hide Actions
;;;===========================================================================

(defun antlr-downcase-literals (&optional transform)
  "Convert all literals in buffer to lower case.
If non-nil, TRANSFORM is used on literals instead of `downcase-region'."
  (interactive)
  (or transform (setq transform 'downcase-region))
  (let ((literals 0))
    (save-excursion
      (goto-char (point-min))
      (antlr-with-syntax-table antlr-action-syntax-table
	(antlr-invalidate-context-cache)
	(while (antlr-re-search-forward "\"\\(\\sw\\(\\sw\\|-\\)*\\)\"" nil)
	  (funcall transform (match-beginning 0) (match-end 0))
	  (incf literals))))
    (message "Transformed %d literals" literals)))

(defun antlr-upcase-literals ()
  "Convert all literals in buffer to upper case."
  (interactive)
  (antlr-downcase-literals 'upcase-region))

(defun antlr-hide-actions (arg &optional silent)
  "Hide or unhide all actions in buffer.
Hide all actions including arguments in brackets if ARG is 1 or if
called interactively without prefix argument.  Hide all actions
excluding arguments in brackets if ARG is 2 or higher.  Unhide all
actions if ARG is 0 or negative.  Never hide actions whose character
length is shorter or equal to `antlr-tiny-action-length'."
  (interactive "p")
  ;; from Emacs/lazy-lock: `save-buffer-state'
  (let ((modified (buffer-modified-p))
	(buffer-undo-list t) (inhibit-read-only t)
	(inhibit-point-motion-hooks t) deactivate-mark ; Emacs only
	before-change-functions after-change-functions
	buffer-file-name buffer-file-truename)
    (if (> arg 0)
	(let ((regexp (if (= arg 1) "[]}]" "}"))
	      (diff (+ (max antlr-tiny-action-length 0) 2)))
	  (antlr-hide-actions 0 t)
	  (save-excursion
	    (goto-char (point-min))
	    (antlr-with-syntax-table antlr-action-syntax-table
	      (antlr-invalidate-context-cache)
	      (while (antlr-re-search-forward regexp nil)
		(let* ((end (point))
		       (beg (antlr-scan-sexps (point) -1 nil t)))
		  (and beg (> end (+ beg diff))
		       (add-text-properties (1+ beg) (1- end)
					    '(invisible t intangible t)))))))
	  (or silent
	      (message "Hide all actions (%s arguments)...done"
		       (if (= arg 1) "including" "excluding"))))
      (remove-text-properties (point-min) (point-max)
			      '(invisible nil intangible nil))
      (or silent
	  (message "Unhide all actions (including arguments)...done")))
    (and (not modified) (buffer-modified-p)
	 (set-buffer-modified-p nil))))


;;;===========================================================================
;;;  Indentation
;;;===========================================================================

(defun antlr-indent-line ()
  "Indent the current line as ANTLR grammar code.
The indentation of non-comment lines are calculated by `c-basic-offset',
multiplied by:
 - the level of the paren/brace/bracket depth,
 - plus 0/2/1, depending on the position inside the rule: header, body,
   exception part,
 - minus 1 if `antlr-indent-item-regexp' matches the beginning of the
   line starting from the first non-blank.

Lines inside block comments are not changed or indented by
`c-indent-line', see `antlr-indent-comment'."
  (let ((orig (point)) bol boi indent syntax)
    (beginning-of-line)
    (setq bol (point))
    (skip-chars-forward " \t")
    (setq boi (point))
    ;; check syntax at beginning of indentation ------------------------------
    (antlr-with-syntax-table antlr-action-syntax-table
      (antlr-invalidate-context-cache)
      (cond ((symbolp (setq syntax (antlr-syntactic-context)))
	     (setq indent nil))		; block-comments, strings, (comments)
	    ((eq (char-after) ?#)	; cpp directive
	     (setq syntax 'cpp)
	     (setq indent 0))		; indentation at 0
	    ((progn
	       (antlr-next-rule -1 t)
	       (if (antlr-search-forward ":") (< boi (1- (point))) t))
	     (setq indent 0))		; in rule header
	    ((if (antlr-search-forward ";") (< boi (point)) t)
	     (setq indent 2))		; in rule body
	    (t
	     (forward-char)
	     (antlr-skip-exception-part nil)
	     (setq indent (if (> (point) boi) 1 0))))) ; in exception part?
    ;; compute the corresponding indentation and indent ----------------------
    (if (null indent)
	(progn
	  (goto-char orig)
	  (and (eq antlr-indent-comment t)
	       (not (eq syntax 'string))
	       (c-indent-line)))
      ;; do it ourselves
      (goto-char boi)
      (unless (symbolp syntax)		; direct indentation
	(antlr-invalidate-context-cache)
	(incf indent (antlr-syntactic-context))
	(and (> indent 0) (looking-at antlr-indent-item-regexp) (decf indent))
	(setq indent (* indent c-basic-offset)))
      ;; the usual major-mode indent stuff:
      (setq orig (- (point-max) orig))
      (unless (= (current-column) indent)
	(delete-region bol boi)
	(beginning-of-line)
	(indent-to indent))
      ;; If initial point was within line's indentation,
      ;; position after the indentation.  Else stay at same point in text.
      (if (> (- (point-max) orig) (point))
	  (goto-char (- (point-max) orig))))))

(defun antlr-indent-command (&optional arg)
  "Indent the current line or insert tabs/spaces.
With optional prefix argument ARG or if the previous command was this
command, insert ARG tabs or spaces according to `indent-tabs-mode'.
Otherwise, indent the current line with `antlr-indent-line'."
  (interactive "P")
  (if (or arg (eq last-command 'antlr-indent-command))
      (insert-tab arg)
    (let ((antlr-indent-comment (and antlr-indent-comment t))) ; dynamic
      (antlr-indent-line))))


;;;===========================================================================
;;;  Mode entry
;;;===========================================================================

(defun antlr-c-common-init ()
  "Like `c-common-init' except menu, auto-hungry and c-style stuff."
  ;; X/Emacs 20 only
  (make-local-variable 'paragraph-start)
  (make-local-variable 'paragraph-separate)
  (make-local-variable 'paragraph-ignore-fill-prefix)
  (make-local-variable 'require-final-newline)
  (make-local-variable 'parse-sexp-ignore-comments)
  (make-local-variable 'indent-line-function)
  (make-local-variable 'indent-region-function)
  (make-local-variable 'comment-start)
  (make-local-variable 'comment-end)
  (make-local-variable 'comment-column)
  (make-local-variable 'comment-start-skip)
  (make-local-variable 'comment-multi-line)
  (make-local-variable 'outline-regexp)
  (make-local-variable 'outline-level)
  (make-local-variable 'adaptive-fill-regexp)
  (make-local-variable 'adaptive-fill-mode)
  (make-local-variable 'imenu-generic-expression) ;set in the mode functions
  (and (boundp 'comment-line-break-function)
       (make-local-variable 'comment-line-break-function))
  ;; Emacs 19.30 and beyond only, AFAIK
  (if (boundp 'fill-paragraph-function)
      (progn
	(make-local-variable 'fill-paragraph-function)
	(setq fill-paragraph-function 'c-fill-paragraph)))
  ;; now set their values
  (setq paragraph-start (concat page-delimiter "\\|$")
	paragraph-separate paragraph-start
	paragraph-ignore-fill-prefix t
	require-final-newline t
	parse-sexp-ignore-comments t
	indent-line-function 'c-indent-line
	indent-region-function 'c-indent-region
	outline-regexp "[^#\n\^M]"
	outline-level 'c-outline-level
	comment-column 32
	comment-start-skip "/\\*+ *\\|// *"
	comment-multi-line nil
	comment-line-break-function 'c-comment-line-break-function
	adaptive-fill-regexp nil
	adaptive-fill-mode nil)
  ;; we have to do something special for c-offsets-alist so that the
  ;; buffer local value has its own alist structure.
  (setq c-offsets-alist (copy-alist c-offsets-alist))
  ;; setup the comment indent variable in a Emacs version portable way
  ;; ignore any byte compiler warnings you might get here
  (make-local-variable 'comment-indent-function)
  (setq comment-indent-function 'c-comment-indent))

(defun antlr-language-for-option (option-value)
  "Find element in `antlr-language-alist' for OPTION-VALUE."
  ;; Like (find OPTION-VALUE antlr-language-alist :key 'cddr :test 'member)
  (let ((seq antlr-language-alist)
	r)
    (while seq
      (setq r (pop seq))
      (if (member option-value (cddr r))
	  (setq seq nil)		; stop
	(setq r nil)))			; no result yet
    r))

;;;###autoload
(defun antlr-mode ()
  "Major mode for editing ANTLR grammar files.
\\{antlr-mode-map}"
  (interactive)
  (c-initialize-cc-mode)		; for java syntax table
  (kill-all-local-variables)
  ;; ANTLR specific ----------------------------------------------------------
  (setq major-mode 'antlr-mode
	mode-name "Antlr")
  (setq local-abbrev-table antlr-mode-abbrev-table)
  (set-syntax-table java-mode-syntax-table)
  (unless antlr-action-syntax-table
    (let ((slist (nth 3 antlr-font-lock-defaults)))
      (setq antlr-action-syntax-table
	    (copy-syntax-table java-mode-syntax-table))
      (while slist
	(modify-syntax-entry (caar slist) (cdar slist)
			     antlr-action-syntax-table)
	(setq slist (cdr slist)))))
  (use-local-map antlr-mode-map)
  (make-local-variable 'antlr-language)
  (unless antlr-language
    (save-excursion
      (goto-char (point-min))
      (setq antlr-language
	    (car (or (and (re-search-forward (cdr antlr-language-limit-n-regexp)
					(car antlr-language-limit-n-regexp)
					t)
			  (antlr-language-for-option (match-string 1)))
		     (antlr-language-for-option nil))))))
  (if (stringp (cadr (assq antlr-language antlr-language-alist)))
      (setq mode-name
	    (concat "Antlr."
		    (cadr (assq antlr-language antlr-language-alist)))))
  ;; indentation, for the C engine -------------------------------------------
  (antlr-c-common-init)
  (setq indent-line-function 'antlr-indent-line
	indent-region-function nil)	; too lazy
  (setq comment-start "// "
 	comment-end "")
  (c-set-style "java")
  (if (eq antlr-language 'c++-mode)
      (setq c-conditional-key c-C++-conditional-key
	    c-comment-start-regexp c-C++-comment-start-regexp
	    c-class-key c-C++-class-key
	    c-extra-toplevel-key c-C++-extra-toplevel-key
	    c-access-key c-C++-access-key
	    c-recognize-knr-p nil)
    (setq c-conditional-key c-Java-conditional-key
	  c-comment-start-regexp c-Java-comment-start-regexp
	  c-class-key c-Java-class-key
	  c-method-key nil
	  c-baseclass-key nil
	  c-recognize-knr-p nil
	  c-access-key c-Java-access-key)
    (and (boundp 'c-inexpr-class-key) (boundp 'c-Java-inexpr-class-key)
	 (setq c-inexpr-class-key c-Java-inexpr-class-key)))
  ;; various -----------------------------------------------------------------
  (make-local-variable 'font-lock-defaults)
  (setq font-lock-defaults antlr-font-lock-defaults)
  (easy-menu-add antlr-mode-menu)
  (make-local-variable 'imenu-create-index-function)
  (setq imenu-create-index-function 'antlr-imenu-create-index-function)
  (make-local-variable 'imenu-generic-expression)
  (setq imenu-generic-expression t)	; fool stupid test
  (and antlr-imenu-name			; there should be a global variable...
       (fboundp 'imenu-add-to-menubar)
       (imenu-add-to-menubar
	(if (stringp antlr-imenu-name) antlr-imenu-name "Index")))
  (antlr-set-tabs)
  (run-hooks 'antlr-mode-hook))

;; In XEmacs, a smarter version of `buffers-menu-grouping-function' could use
;; the following property.  The header of the submenu would be "Antlr" instead
;; of "Antlr/C++" or "Antlr/Java" (depending on the buffer ordering).
(put 'antlr-mode 'mode-name "Antlr")

;;;###autoload
(defun antlr-set-tabs ()
  "Use ANTLR's convention for TABs according to `antlr-tab-offset-alist'.
Used in `antlr-mode'.  Also a useful function in `java-mode-hook'."
  (if buffer-file-name
      (let ((alist antlr-tab-offset-alist) elem)
	(while alist
	  (setq elem (pop alist))
	  (and (or (null (car elem)) (eq (car elem) major-mode))
	       (or (null (cadr elem))
		   (string-match (cadr elem) buffer-file-name))
	       (setq tab-width (caddr elem)
		     indent-tabs-mode (cadddr elem)
		     alist nil))))))

;;; antlr-mode.el ends here

; LocalWords:  antlr ANother ANTLR's Cpp Lexer TreeParser esp refs VALUEs ea ee
; LocalWords:  Java's Nomencl ruledef tokendef ruleref tokenref setType ader
; LocalWords:  ivate syntab lexer treeparser lic rotected rivate bor boi AFAIK
; LocalWords:  slist knr inexpr