--- /dev/null
+;;; company-elisp.el --- a company-mode completion back-end for emacs-lisp-mode
+
+;; Copyright (C) 2009 Free Software Foundation, Inc.
+
+;; Author: Nikolaj Schumacher
+
+;; 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'company)
+(eval-when-compile (require 'cl))
+(require 'help-mode)
+
+(defcustom company-elisp-detect-function-context t
+ "*If enabled, offer lisp functions only in appropriate contexts.
+Functions are offered for completion only after ' and \(."
+ :group 'company
+ :type '(choice (const :tag "Off" nil)
+ (const :tag "On" t)))
+
+(defun company-grab-lisp-symbol ()
+ (let ((prefix (company-grab-symbol)))
+ (if prefix
+ (unless (and (company-in-string-or-comment)
+ (/= (char-before (- (point) (length prefix))) ?`))
+ prefix)
+ 'stop)))
+
+(defun company-elisp-predicate (symbol)
+ (or (boundp symbol)
+ (fboundp symbol)))
+
+(defvar company-elisp-parse-limit 30)
+(defvar company-elisp-parse-depth 100)
+
+(defvar company-elisp-binding-regexp
+ (concat "([ \t\n]*\\_<" (regexp-opt '("let" "defun" "defmacro" "defsubst"
+ "lambda" "lexical-let" "flet" "labels"))
+ "\\*?")
+ "Regular expression matching sexps containing variable bindings.")
+
+(defvar company-elisp-binding-regexp-1
+ (concat "([ \t\n]*\\_<" (regexp-opt '("dolist" "dotimes")))
+ "Regular expression matching sexps containing one variable binding.")
+
+(defun company-elisp-parse-local (prefix vars)
+ (let ((regexp (concat "[ \t\n]*\\(\\_<" (regexp-quote prefix)
+ "\\(?:\\sw\\|\\s_\\)*\\_>\\)"))
+ (pos (point)))
+ (ignore-errors
+ (save-excursion
+ (dotimes (i company-elisp-parse-depth)
+ (up-list -1)
+ (save-excursion
+ (cond
+ ((looking-at company-elisp-binding-regexp)
+ (down-list 2)
+ (ignore-errors
+ (dotimes (i company-elisp-parse-limit)
+ (save-excursion
+ (when (looking-at "[ \t\n]*(")
+ (down-list 1))
+ (and (looking-at regexp)
+ ;; Don't add incomplete text as candidate.
+ (not (eq (match-end 0) pos))
+ (add-to-list 'vars (match-string-no-properties 1))))
+ (forward-sexp))))
+ ((looking-at company-elisp-binding-regexp-1)
+ (down-list 2)
+ (and (looking-at regexp)
+ ;; Don't add incomplete text as candidate.
+ (not (eq (match-end 0) pos))
+ (add-to-list 'vars (match-string-no-properties 1)))))))))
+ vars))
+
+(defun company-elisp-candidates (prefix)
+ (let* ((completion-ignore-case nil)
+ (before (char-before (- (point) (length prefix))))
+ (predicate (if (and company-elisp-detect-function-context
+ (not (eq before ?')))
+ (if (eq before ?\()
+ 'fboundp
+ 'boundp)
+ 'company-elisp-predicate))
+ (candidates (all-completions prefix obarray predicate)))
+ (company-elisp-parse-local prefix candidates)))
+
+(defun company-elisp-doc (symbol)
+ (let* ((symbol (intern symbol))
+ (doc (if (fboundp symbol)
+ (documentation symbol t)
+ (documentation-property symbol 'variable-documentation t))))
+ (and (stringp doc)
+ (string-match ".*$" doc)
+ (match-string 0 doc))))
+
+;;;###autoload
+(defun company-elisp (command &optional arg &rest ignored)
+ "A `company-mode' completion back-end for `emacs-lisp-mode'."
+ (interactive (list 'interactive))
+ (case command
+ ('interactive (company-begin-backend 'company-elisp))
+ ('prefix (and (eq (derived-mode-p 'emacs-lisp-mode) 'emacs-lisp-mode)
+ (company-grab-lisp-symbol)))
+ ('candidates (company-elisp-candidates arg))
+ ('meta (company-elisp-doc arg))
+ ('doc-buffer (let ((symbol (intern arg)))
+ (save-window-excursion
+ (when (or (ignore-errors (describe-function symbol))
+ (ignore-errors (describe-variable symbol)))
+ (help-buffer)))))
+ ('location (let ((sym (intern arg)))
+ (or (ignore-errors (find-definition-noselect sym nil))
+ (ignore-errors (find-definition-noselect sym 'defvar))
+ (ignore-errors (find-definition-noselect sym t)))))))
+
+(provide 'company-elisp)
+;;; company-elisp.el ends here