;;; elint.el --- Lint Emacs Lisp

;; Copyright (C) 1997, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
;;   2009  Free Software Foundation, Inc.

;; Author: Peter Liljenberg <petli@lysator.liu.se>
;; Created: May 1997
;; Keywords: lisp

;; 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/>.

;;; Commentary:

;; This is a linter for Emacs Lisp. Currently, it mainly catches
;; mispellings and undefined variables, although it can also catch
;; function calls with the wrong number of arguments.

;; Before using, call `elint-initialize' to set up some argument
;; data. This takes a while. Then call elint-current-buffer or
;; elint-defun to lint a buffer or a defun.

;; The linter will try to "include" any require'd libraries to find
;; the variables defined in those. There is a fair amount of voodoo
;; involved in this, but it seems to work in normal situations.

;;; History:

;;; To do:

;; * A list of all standard Emacs variables would be nice to have...
;; * Adding type checking. (Stop that sniggering!)

;;; Code:

(defvar elint-log-buffer "*Elint*"
  "*The buffer to insert lint messages in.")

;;;
;;; Data
;;;

(defconst elint-standard-variables
  '(abbrev-mode auto-fill-function buffer-auto-save-file-name
     buffer-backed-up buffer-display-count buffer-display-table buffer-display-time buffer-file-coding-system buffer-file-format
     buffer-file-name buffer-file-number buffer-file-truename
     buffer-file-type buffer-invisibility-spec buffer-offer-save
     buffer-read-only buffer-saved-size buffer-undo-list
     cache-long-line-scans case-fold-search ctl-arrow cursor-type comment-column
     default-directory defun-prompt-regexp desktop-save-buffer enable-multibyte-characters fill-column fringes-outside-margins goal-column
     header-line-format indicate-buffer-boundaries indicate-empty-lines
     left-fringe-width
     left-margin left-margin-width line-spacing local-abbrev-table local-write-file-hooks major-mode
     mark-active mark-ring mode-line-buffer-identification
     mode-line-format mode-line-modified mode-line-process mode-name
     overwrite-mode
     point-before-scroll right-fringe-width right-margin-width
     scroll-bar-width scroll-down-aggressively scroll-up-aggressively selective-display
     selective-display-ellipses tab-width truncate-lines vc-mode vertical-scroll-bar)
  "Standard buffer local vars.")

(defconst elint-unknown-builtin-args
  '((while test &rest forms)
    (insert-before-markers-and-inherit &rest text)
    (catch tag &rest body)
    (and &rest args)
    (funcall func &rest args)
    (insert &rest args)
    (vconcat &rest args)
    (run-hook-with-args hook &rest args)
    (message-or-box string &rest args)
    (save-window-excursion &rest body)
    (append &rest args)
    (logior &rest args)
    (progn &rest body)
    (insert-and-inherit &rest args)
    (message-box string &rest args)
    (prog2 x y &rest body)
    (prog1 first &rest body)
    (insert-before-markers &rest args)
    (call-process-region start end program &optional delete
			 destination display &rest args)
    (concat &rest args)
    (vector &rest args)
    (run-hook-with-args-until-success hook &rest args)
    (track-mouse &rest body)
    (unwind-protect bodyform &rest unwindforms)
    (save-restriction &rest body)
    (quote arg)
    (make-byte-code &rest args)
    (or &rest args)
    (cond &rest clauses)
    (start-process name buffer program &rest args)
    (run-hook-with-args-until-failure hook &rest args)
    (if cond then &rest else)
    (apply function &rest args)
    (format string &rest args)
    (encode-time second minute hour day month year &optional zone)
    (min &rest args)
    (logand &rest args)
    (logxor &rest args)
    (max &rest args)
    (list &rest args)
    (message string &rest args)
    (defvar symbol init doc)
    (call-process program &optional infile destination display &rest args)
    (with-output-to-temp-buffer bufname &rest body)
    (nconc &rest args)
    (save-excursion &rest body)
    (run-hooks &rest hooks)
    (/ x y &rest zs)
    (- x &rest y)
    (+ &rest args)
    (* &rest args)
    (interactive &optional args))
  "Those built-ins for which we can't find arguments.")

;;;
;;; ADT: top-form
;;;

(defsubst elint-make-top-form (form pos)
  "Create a top form.
FORM is the form, and POS is the point where it starts in the buffer."
  (cons form pos))

(defsubst elint-top-form-form (top-form)
  "Extract the form from a TOP-FORM."
  (car top-form))

(defsubst elint-top-form-pos (top-form)
  "Extract the position from a TOP-FORM."
  (cdr top-form))

;;;
;;; ADT: env
;;;

(defsubst elint-make-env ()
  "Create an empty environment."
  (list (list nil) nil nil))

(defsubst elint-env-add-env (env newenv)
  "Augment ENV with NEWENV.
None of them is modified, and the new env is returned."
  (list (append (car env) (car newenv))
	(append (car (cdr env)) (car (cdr newenv)))
	(append (car (cdr (cdr env))) (car (cdr (cdr newenv))))))

(defsubst elint-env-add-var (env var)
  "Augment ENV with the variable VAR.
The new environment is returned, the old is unmodified."
  (cons (cons (list var) (car env)) (cdr env)))

(defsubst elint-env-add-global-var (env var)
  "Augment ENV with the variable VAR.
ENV is modified so VAR is seen everywhere.
ENV is returned."
  (nconc (car env) (list (list var)))
  env)

(defsubst elint-env-find-var (env var)
  "Non-nil if ENV contains the variable VAR.
Actually, a list with VAR as a single element is returned."
  (assq var (car env)))

(defsubst elint-env-add-func (env func args)
  "Augment ENV with the function FUNC, which has the arguments ARGS.
The new environment is returned, the old is unmodified."
  (list (car env)
	(cons (list func args) (car (cdr env)))
	(car (cdr (cdr env)))))

(defsubst elint-env-find-func (env func)
  "Non-nil if ENV contains the function FUNC.
Actually, a list of (FUNC ARGS) is returned."
  (assq func (car (cdr env))))

(defsubst elint-env-add-macro (env macro def)
  "Augment ENV with the macro named MACRO.
DEF is the macro definition (a lambda expression or similar).
The new environment is returned, the old is unmodified."
  (list (car env)
	(car (cdr env))
	(cons (cons macro def) (car (cdr (cdr env))))))

(defsubst elint-env-macro-env (env)
  "Return the macro environment of ENV.
This environment can be passed to `macroexpand'."
  (car (cdr (cdr env))))

(defsubst elint-env-macrop (env macro)
  "Non-nil if ENV contains MACRO."
  (assq macro (elint-env-macro-env env)))

;;;
;;; User interface
;;;

(defun elint-current-buffer ()
  "Lint the current buffer."
  (interactive)
  (elint-clear-log (format "Linting %s" (if (buffer-file-name)
					    (buffer-file-name)
					  (buffer-name))))
  (elint-display-log)
  (mapc 'elint-top-form (elint-update-env))

  ;; Tell the user we're finished. This is terribly klugy: we set
  ;; elint-top-form-logged so elint-log-message doesn't print the
  ;; ** top form ** header...
  (let ((elint-top-form-logged t))
    (elint-log-message "\nLinting complete.\n")))

(defun elint-defun ()
  "Lint the function at point."
  (interactive)
  (save-excursion
    (if (not (beginning-of-defun))
	(error "Lint what?"))

    (let ((pos (point))
	  (def (read (current-buffer))))
      (elint-display-log)

      (elint-update-env)
      (elint-top-form (elint-make-top-form def pos)))))

;;;
;;; Top form functions
;;;

(defvar elint-buffer-env nil
  "The environment of a elisp buffer.
Will be local in linted buffers.")

(defvar elint-buffer-forms nil
  "The top forms in a buffer.
Will be local in linted buffers.")

(defvar elint-last-env-time nil
  "The last time the buffers env was updated.
Is measured in buffer-modified-ticks and is local in linted buffers.")

(defun elint-update-env ()
  "Update the elint environment in the current buffer.
Don't do anything if the buffer hasn't been changed since this
function was called the last time.
Returns the forms."
  (if (and (local-variable-p 'elint-buffer-env (current-buffer))
	   (local-variable-p 'elint-buffer-forms (current-buffer))
	   (local-variable-p 'elint-last-env-time (current-buffer))
	   (= (buffer-modified-tick) elint-last-env-time))
      ;; Env is up to date
      elint-buffer-forms
    ;; Remake env
    (set (make-local-variable 'elint-buffer-forms) (elint-get-top-forms))
    (set (make-local-variable 'elint-buffer-env)
	 (elint-init-env elint-buffer-forms))
    (set (make-local-variable 'elint-last-env-time) (buffer-modified-tick))
    elint-buffer-forms))

(defun elint-get-top-forms ()
  "Collect all the top forms in the current buffer."
  (save-excursion
    (let ((tops nil))
      (goto-char (point-min))
      (while (elint-find-next-top-form)
	(let ((pos (point)))
	  (condition-case nil
	      (setq tops (cons
			  (elint-make-top-form (read (current-buffer)) pos)
			  tops))
	    (end-of-file
	     (goto-char pos)
	     (end-of-line)
	     (error "Missing ')' in top form: %s" (buffer-substring pos (point)))))
	  ))
      (nreverse tops))))

(defun elint-find-next-top-form ()
  "Find the next top form from point.
Return nil if there are no more forms, t otherwise."
  (parse-partial-sexp (point) (point-max) nil t)
  (not (eobp)))

(defun elint-init-env (forms)
  "Initialize the environment from FORMS."
  (let ((env (elint-make-env))
	form)
    (while forms
      (setq form (elint-top-form-form (car forms))
	    forms (cdr forms))
      (cond
       ;; Add defined variable
       ((memq (car form) '(defvar defconst defcustom))
	(setq env (elint-env-add-var env (car (cdr form)))))
       ;; Add function
       ((memq (car form) '(defun defsubst))
	(setq env (elint-env-add-func env (car (cdr form))
				      (car (cdr (cdr form))))))
       ;; Add macro, both as a macro and as a function
       ((eq (car form) 'defmacro)
	(setq env (elint-env-add-macro env (car (cdr form))
				       (cons 'lambda
					     (cdr (cdr form))))
	      env (elint-env-add-func env (car (cdr form))
				      (car (cdr (cdr form))))))

       ;; Import variable definitions
       ((eq (car form) 'require)
	(let ((name (eval (car (cdr form))))
	      (file (eval (car (cdr (cdr form))))))
	  (setq env (elint-add-required-env env name file))))
       ))
    env))

(defun elint-add-required-env (env name file)
  "Augment ENV with the variables definied by feature NAME in FILE."
  (condition-case nil
      (let* ((libname (if (stringp file)
			  file
			(symbol-name name)))

	     ;; First try to find .el files, then the raw name
	     (lib1 (locate-library (concat libname ".el") t))
	     (lib (if lib1 lib1 (locate-library libname t))))
	;; Clear the messages :-/
	(message nil)
	(if lib
	    (save-excursion
	      (set-buffer (find-file-noselect lib))
	      (elint-update-env)
	      (setq env (elint-env-add-env env elint-buffer-env)))
	  (error "dummy error...")))
    (error
     (ding)
     (message "Can't get variables from require'd library %s" name)))
  env)

(defun regexp-assoc (regexp alist)
  "Search for a key matching REGEXP in ALIST."
  (let ((res nil))
    (while (and alist (not res))
      (if (and (stringp (car (car alist)))
	       (string-match regexp (car (car alist))))
	  (setq res (car alist))
	(setq alist (cdr alist))))
    res))

(defvar elint-top-form nil
  "The currently linted top form, or nil.")

(defvar elint-top-form-logged nil
  "T if the currently linted top form has been mentioned in the log buffer.")

(defun elint-top-form (form)
  "Lint a top FORM."
  (let ((elint-top-form form)
	(elint-top-form-logged nil))
    (elint-form (elint-top-form-form form) elint-buffer-env)))

;;;
;;; General form linting functions
;;;

(defconst elint-special-forms
  '((let . elint-check-let-form)
    (let* . elint-check-let-form)
    (setq . elint-check-setq-form)
    (quote . elint-check-quote-form)
    (cond . elint-check-cond-form)
    (lambda . elint-check-defun-form)
    (function . elint-check-function-form)
    (setq-default . elint-check-setq-form)
    (defun . elint-check-defun-form)
    (defsubst . elint-check-defun-form)
    (defmacro . elint-check-defun-form)
    (defvar . elint-check-defvar-form)
    (defconst . elint-check-defvar-form)
    (defcustom . elint-check-defcustom-form)
    (macro . elint-check-macro-form)
    (condition-case . elint-check-condition-case-form))
  "Functions to call when some special form should be linted.")

(defun elint-form (form env)
  "Lint FORM in the environment ENV.
The environment created by the form is returned."
  (cond
   ((consp form)
    (let ((func (cdr (assq (car form) elint-special-forms))))
      (if func
	  ;; Special form
	  (funcall func form env)

	(let* ((func (car form))
	       (args (elint-get-args func env))
	       (argsok t))
	  (cond
	   ((eq args 'undefined)
	    (setq argsok nil)
	    (elint-error "Call to undefined function: %s" form))

	   ((eq args 'unknown) nil)

	   (t (setq argsok (elint-match-args form args))))

	  ;; Is this a macro?
	  (if (elint-env-macrop env func)
	      ;; Macro defined in buffer, expand it
	      (if argsok
		  (elint-form (macroexpand form (elint-env-macro-env env)) env)
		env)

	    (let ((fcode (if (symbolp func)
			     (if (fboundp func)
				 (indirect-function func)
			       nil)
			   func)))
	      (if (and (listp fcode) (eq (car fcode) 'macro))
		  ;; Macro defined outside buffer
		  (if argsok
		      (elint-form (macroexpand form) env)
		    env)
		;; Function, lint its parameters
		(elint-forms (cdr form) env))))
	  ))
      ))
   ((symbolp form)
    ;; :foo variables are quoted
    (if (and (/= (aref (symbol-name form) 0) ?:)
	     (elint-unbound-variable form env))
	(elint-warning "Reference to unbound symbol: %s" form))
    env)

   (t env)
   ))

(defun elint-forms (forms env)
  "Lint the FORMS, accumulating an environment, starting with ENV."
  ;; grumblegrumbletailrecursiongrumblegrumble
  (while forms
    (setq env (elint-form (car forms) env)
	  forms (cdr forms)))
  env)

(defun elint-unbound-variable (var env)
  "T if VAR is unbound in ENV."
  (not (or (eq var nil)
	   (eq var t)
	   (elint-env-find-var env var)
	   (memq var elint-standard-variables))))

;;;
;;; Function argument checking
;;;

(defun elint-match-args (arglist argpattern)
  "Match ARGLIST against ARGPATTERN."

  (let ((state 'all)
	(al (cdr arglist))
	(ap argpattern)
	(ok t))
    (while
	(cond
	 ((and (null al) (null ap)) nil)
	 ((eq (car ap) '&optional)
	  (setq state 'optional)
	  (setq ap (cdr ap))
	  t)
	 ((eq (car ap) '&rest)
	  nil)
	 ((or (and (eq state 'all) (or (null al) (null ap)))
	      (and (eq state 'optional) (and al (null ap))))
	  (elint-error "Wrong number of args: %s, %s" arglist argpattern)
	  (setq ok nil)
	  nil)
	 ((and (eq state 'optional) (null al))
	  nil)
	 (t (setq al (cdr al)
		  ap (cdr ap))
	    t)))
    ok))

(defun elint-get-args (func env)
  "Find the args of FUNC in ENV.
Returns `unknown' if we couldn't find arguments."
  (let ((f (elint-env-find-func env func)))
    (if f
	(car (cdr f))
      (if (symbolp func)
	  (if (fboundp func)
	      (let ((fcode (indirect-function func)))
		(if (subrp fcode)
		    (let ((args (get func 'elint-args)))
		      ;; FIXME builtins with no args have args = nil.
		      (if args args 'unknown))
		  (elint-find-args-in-code fcode)))
	    'undefined)
	(elint-find-args-in-code func)))))

(defun elint-find-args-in-code (code)
  "Extract the arguments from CODE.
CODE can be a lambda expression, a macro, or byte-compiled code."
  (cond
   ((byte-code-function-p code)
    (aref code 0))
   ((and (listp code) (eq (car code) 'lambda))
    (car (cdr code)))
   ((and (listp code) (eq (car code) 'macro))
    (elint-find-args-in-code (cdr code)))
   (t 'unknown)))

;;;
;;; Functions to check some special forms
;;;

(defun elint-check-cond-form (form env)
  "Lint a cond FORM in ENV."
  (setq form (cdr form))
  (while form
    (if (consp (car form))
	(elint-forms  (car form) env)
      (elint-error "cond clause should be a list: %s" (car form)))
    (setq form (cdr form)))
  env)

(defun elint-check-defun-form (form env)
  "Lint a defun/defmacro/lambda FORM in ENV."
  (setq form (if (eq (car form) 'lambda) (cdr form) (cdr (cdr form))))
  (mapc (function (lambda (p)
		    (or (memq p '(&optional &rest))
			(setq env (elint-env-add-var env p)))
		    ))
	(car form))
  (elint-forms (cdr form) env))

(defun elint-check-let-form (form env)
  "Lint the let/let* FORM in ENV."
  (let ((varlist (car (cdr form))))
    (if (not varlist)
	(progn
	  (elint-error "Missing varlist in let: %s" form)
	  env)

      ;; Check for (let (a (car b)) ...) type of error
      (if (and (= (length varlist) 2)
	       (symbolp (car varlist))
	       (listp (car (cdr varlist)))
	       (fboundp (car (car (cdr varlist)))))
	  (elint-warning "Suspect varlist: %s" form))

      ;; Add variables to environment, and check the init values
      (let ((newenv env))
	(mapc (function (lambda (s)
			  (cond
			   ((symbolp s)
			    (setq newenv (elint-env-add-var newenv s)))
			   ((and (consp s) (<= (length s) 2))
			    (elint-form (car (cdr s))
					(if (eq (car form) 'let)
					    env
					  newenv))
			    (setq newenv
				  (elint-env-add-var newenv (car s))))
			   (t (elint-error
			       "Malformed `let' declaration: %s" s))
			   )))
	      varlist)

	;; Lint the body forms
	(elint-forms (cdr (cdr form)) newenv)
	))))

(defun elint-check-setq-form (form env)
  "Lint the setq FORM in ENV."
  (or (= (mod (length form) 2) 1)
      (elint-error "Missing value in setq: %s" form))

  (let ((newenv env)
	sym val)
    (setq form (cdr form))
    (while form
      (setq sym (car form)
	    val (car (cdr form))
	    form (cdr (cdr form)))
      (if (symbolp sym)
	  (if (elint-unbound-variable sym newenv)
	      (elint-warning "Setting previously unbound symbol: %s" sym))
	(elint-error "Setting non-symbol in setq: %s" sym))
      (elint-form val newenv)
      (if (symbolp sym)
	  (setq newenv (elint-env-add-var newenv sym))))
    newenv))

(defun elint-check-defvar-form (form env)
  "Lint the defvar/defconst FORM in ENV."
  (if (or (= (length form) 2)
	  (= (length form) 3)
	  (and (= (length form) 4) (stringp (nth 3 form))))
          (elint-env-add-global-var (elint-form (nth 2 form) env)
			     (car (cdr form)))
    (elint-error "Malformed variable declaration: %s" form)
    env))

(defun elint-check-defcustom-form (form env)
  "Lint the defcustom FORM in ENV."
  (if (and (> (length form) 3)
	   ;; even no. of keyword/value args ?
	   (zerop (logand (length form) 1)))
      (elint-env-add-global-var (elint-form (nth 2 form) env)
				(car (cdr form)))
    (elint-error "Malformed variable declaration: %s" form)
    env))

(defun elint-check-function-form (form env)
  "Lint the function FORM in ENV."
  (let ((func (car (cdr-safe form))))
    (cond
     ((symbolp func)
      (or (elint-env-find-func env func)
	  (fboundp func)
	  (elint-warning "Reference to undefined function: %s" form))
      env)
     ((and (consp func) (memq (car func) '(lambda macro)))
      (elint-form func env))
     ((stringp func) env)
     (t (elint-error "Not a function object: %s" form)
	env)
     )))

(defun elint-check-quote-form (form env)
  "Lint the quote FORM in ENV."
  env)

(defun elint-check-macro-form (form env)
  "Check the macro FORM in ENV."
  (elint-check-function-form (list (car form) (cdr form)) env))

(defun elint-check-condition-case-form (form env)
  "Check the condition-case FORM in ENV."
  (let ((resenv env))
    (if (< (length form) 3)
	(elint-error "Malformed condition-case: %s" form)
      (or (symbolp (car (cdr form)))
	  (elint-warning "First parameter should be a symbol: %s" form))
      (setq resenv (elint-form (nth 2 form) env))

      (let ((newenv (elint-env-add-var env (car (cdr form))))
	    (errforms (nthcdr 3 form))
	    errlist)
	(while errforms
	  (setq errlist (car (car errforms)))
	  (mapc (function (lambda (s)
			    (or (get s 'error-conditions)
				(get s 'error-message)
				(elint-warning
				 "Not an error symbol in error handler: %s" s))))
		(cond
		  ((symbolp errlist) (list errlist))
		  ((listp errlist) errlist)
		  (t (elint-error "Bad error list in error handler: %s"
				  errlist)
		     nil))
		)
	  (elint-forms (cdr (car errforms)) newenv)
	  (setq errforms (cdr errforms))
	  )))
    resenv))

;;;
;;; Message functions
;;;

;; elint-error and elint-warning are identical, but they might change
;; to reflect different seriousness of linting errors

(defun elint-error (string &rest args)
  "Report a linting error.
STRING and ARGS are thrown on `format' to get the message."
  (let ((errstr (apply 'format string args)))
    (elint-log-message errstr)
    ))

(defun elint-warning (string &rest args)
  "Report a linting warning.
STRING and ARGS are thrown on `format' to get the message."
  (let ((errstr (apply 'format string args)))
    (elint-log-message errstr)
    ))

(defun elint-log-message (errstr)
  "Insert ERRSTR last in the lint log buffer."
  (save-excursion
    (set-buffer (elint-get-log-buffer))
    (goto-char (point-max))
    (or (bolp) (newline))

    ;; Do we have to say where we are?
    (if elint-top-form-logged
	nil
      (insert
       (let* ((form (elint-top-form-form elint-top-form))
	      (top (car form)))
	 (cond
	  ((memq top '(defun defsubst))
	   (format "\n** function %s **\n" (car (cdr form))))
	  ((eq top 'defmacro)
	   (format "\n** macro %s **\n" (car (cdr form))))
	  ((memq top '(defvar defconst))
	   (format "\n** variable %s **\n" (car (cdr form))))
	  (t "\n** top level expression **\n"))))
      (setq elint-top-form-logged t))

    (insert errstr)
    (newline)))

(defun elint-clear-log (&optional header)
  "Clear the lint log buffer.
Insert HEADER followed by a blank line if non-nil."
  (save-excursion
    (set-buffer (elint-get-log-buffer))
    (erase-buffer)
    (if header
	(progn
	  (insert header)
	  (newline))
      )))

(defun elint-display-log ()
  "Display the lint log buffer."
  (let ((pop-up-windows t))
    (display-buffer (elint-get-log-buffer))
    (sit-for 0)))

(defun elint-get-log-buffer ()
  "Return a log buffer for elint."
  (let ((buf (get-buffer elint-log-buffer)))
    (if buf
	buf
      (let ((oldbuf (current-buffer)))
	(prog1
	    (set-buffer (get-buffer-create elint-log-buffer))
	  (setq truncate-lines t)
	  (set-buffer oldbuf)))
      )))

;;;
;;; Initializing code
;;;

;;;###autoload
(defun elint-initialize ()
  "Initialize elint."
  (interactive)
  (mapc (function (lambda (x)
		    (or (not (symbolp (car x)))
			(eq (cdr x) 'unknown)
			(put (car x) 'elint-args (cdr x)))))
	(elint-find-builtin-args))
  (mapcar (function (lambda (x)
		      (put (car x) 'elint-args (cdr x))))
	  elint-unknown-builtin-args))


(defun elint-find-builtins ()
  "Returns a list of all built-in functions."
  (let ((subrs nil))
    (mapatoms (lambda (s) (if (and (fboundp s) (subrp (symbol-function s)))
			      (setq subrs (cons s subrs)))))
    subrs
    ))

(defun elint-find-builtin-args (&optional list)
  "Returns a list of the built-in functions and their arguments.

If LIST is nil, call `elint-find-builtins' to get a list of all built-in
functions, otherwise use LIST.

Each functions is represented by a cons cell:
\(function-symbol . args)
If no documentation could be found args will be `unknown'."
  (mapcar (lambda (f)
	    (let ((doc (documentation f t)))
	      (or (and doc
		       (string-match "\n\n(fn\\(.*)\\)\\'" doc)
		       (ignore-errors
			(read (format "(%s %s" f (match-string 1 doc)))))
		  (cons f 'unknown))))
	  (or list (elint-find-builtins))))

(provide 'elint)

;; arch-tag: b2f061e2-af84-4ddc-8e39-f5e969ac228f
;;; elint.el ends here
