+(require 'cl-lib)
+(require 'help-mode)
+(require 'find-func)
+
+(defgroup company-elisp nil
+ "Completion backend for Emacs Lisp."
+ :group 'company)
+
+(defcustom company-elisp-detect-function-context t
+ "If enabled, offer Lisp functions only in appropriate contexts.
+Functions are offered for completion only after ' and \(."
+ :type '(choice (const :tag "Off" nil)
+ (const :tag "On" t)))
+
+(defcustom company-elisp-show-locals-first t
+ "If enabled, locally bound variables and functions are displayed
+first in the candidates list."
+ :type '(choice (const :tag "Off" nil)
+ (const :tag "On" t)))
+
+(defun company-elisp--prefix ()
+ (let ((prefix (company-grab-symbol)))
+ (if prefix
+ (when (if (company-in-string-or-comment)
+ (= (char-before (- (point) (length prefix))) ?`)
+ (company-elisp--should-complete))
+ prefix)
+ 'stop)))
+
+(defun company-elisp--predicate (symbol)
+ (or (boundp symbol)
+ (fboundp symbol)
+ (facep symbol)
+ (featurep symbol)))
+
+(defun company-elisp--fns-regexp (&rest names)
+ (concat "\\_<\\(?:cl-\\)?" (regexp-opt names) "\\*?\\_>"))
+
+(defvar company-elisp-parse-limit 30)
+(defvar company-elisp-parse-depth 100)
+
+(defvar company-elisp-defun-names '("defun" "defmacro" "defsubst"))
+
+(defvar company-elisp-var-binding-regexp
+ (apply #'company-elisp--fns-regexp "let" "lambda" "lexical-let"
+ company-elisp-defun-names)
+ "Regular expression matching head of a multiple variable bindings form.")
+
+(defvar company-elisp-var-binding-regexp-1
+ (company-elisp--fns-regexp "dolist" "dotimes")
+ "Regular expression matching head of a form with one variable binding.")
+
+(defvar company-elisp-fun-binding-regexp
+ (company-elisp--fns-regexp "flet" "labels")
+ "Regular expression matching head of a function bindings form.")
+
+(defvar company-elisp-defuns-regexp
+ (concat "([ \t\n]*"
+ (apply #'company-elisp--fns-regexp company-elisp-defun-names)))
+
+(defun company-elisp--should-complete ()
+ (let ((start (point))
+ (depth (car (syntax-ppss))))
+ (not
+ (when (> depth 0)
+ (save-excursion
+ (up-list (- depth))
+ (when (looking-at company-elisp-defuns-regexp)
+ (forward-char)
+ (forward-sexp 1)
+ (unless (= (point) start)
+ (condition-case nil
+ (let ((args-end (scan-sexps (point) 2)))
+ (or (null args-end)
+ (> args-end start)))
+ (scan-error
+ t)))))))))
+
+(defun company-elisp--locals (prefix functions-p)
+ (let ((regexp (concat "[ \t\n]*\\(\\_<" (regexp-quote prefix)
+ "\\(?:\\sw\\|\\s_\\)*\\_>\\)"))
+ (pos (point))
+ res)
+ (condition-case nil
+ (save-excursion
+ (dotimes (_ company-elisp-parse-depth)
+ (up-list -1)
+ (save-excursion
+ (when (eq (char-after) ?\()
+ (forward-char 1)
+ (when (ignore-errors
+ (save-excursion (forward-list)
+ (<= (point) pos)))
+ (skip-chars-forward " \t\n")
+ (cond
+ ((looking-at (if functions-p
+ company-elisp-fun-binding-regexp
+ company-elisp-var-binding-regexp))
+ (down-list 1)
+ (condition-case nil
+ (dotimes (_ company-elisp-parse-limit)
+ (save-excursion
+ (when (looking-at "[ \t\n]*(")
+ (down-list 1))
+ (when (looking-at regexp)
+ (cl-pushnew (match-string-no-properties 1) res)))
+ (forward-sexp))
+ (scan-error nil)))
+ ((unless functions-p
+ (looking-at company-elisp-var-binding-regexp-1))
+ (down-list 1)
+ (when (looking-at regexp)
+ (cl-pushnew (match-string-no-properties 1) res)))))))))
+ (scan-error nil))
+ res))
+
+(defun company-elisp-candidates (prefix)
+ (let* ((predicate (company-elisp--candidates-predicate prefix))
+ (locals (company-elisp--locals prefix (eq predicate 'fboundp)))
+ (globals (company-elisp--globals prefix predicate))
+ (locals (cl-loop for local in locals
+ when (not (member local globals))
+ collect local)))
+ (if company-elisp-show-locals-first
+ (append (sort locals 'string<)
+ (sort globals 'string<))
+ (append locals globals))))
+
+(defun company-elisp--globals (prefix predicate)
+ (all-completions prefix obarray predicate))
+
+(defun company-elisp--candidates-predicate (prefix)
+ (let* ((completion-ignore-case nil)
+ (beg (- (point) (length prefix)))
+ (before (char-before beg)))
+ (if (and company-elisp-detect-function-context
+ (not (memq before '(?' ?`))))
+ (if (and (eq before ?\()
+ (not
+ (save-excursion
+ (ignore-errors
+ (goto-char (1- beg))
+ (or (company-elisp--before-binding-varlist-p)
+ (progn
+ (up-list -1)
+ (company-elisp--before-binding-varlist-p)))))))
+ 'fboundp
+ 'boundp)
+ 'company-elisp--predicate)))