;; exact structure of the original argument list as long as the new argument
;; list takes a compatible number/magnitude of actual arguments.
-;; @@@ Definition of subr argument lists:
-;; ======================================
-;; When advice constructs the advised definition of a function it has to
-;; know the argument list of the original function. For functions and macros
-;; the argument list can be determined from the actual definition, however,
-;; for subrs there is no such direct access available. In Lemacs and for some
-;; subrs in Emacs-19 the argument list of a subr can be determined from
-;; its documentation string, in a v18 Emacs even that is not possible. If
-;; advice cannot at all determine the argument list of a subr it uses
-;; `(&rest ad-subr-args)' which will always work but is inefficient because
-;; it conses up arguments. The macro `ad-define-subr-args' can be used by
-;; the advice programmer to explicitly tell advice about the argument list
-;; of a certain subr, for example,
-;;
-;; (ad-define-subr-args 'fset '(sym newdef))
-;;
-;; is used by advice itself to tell a v18 Emacs about the arguments of `fset'.
-;; The following can be used to undo such a definition:
-;;
-;; (ad-undefine-subr-args 'fset)
-;;
-;; The argument list definition is stored on the property list of the subr
-;; name symbol. When an argument list could be determined from the
-;; documentation string it will be cached under that property. The general
-;; mechanism for looking up the argument list of a subr is the following:
-;; 1) look for a definition stored on the property list
-;; 2) if that failed try to infer it from the documentation string and
-;; if successful cache it on the property list
-;; 3) otherwise use `(&rest ad-subr-args)'
-
;; @@ Activation and deactivation:
;; ===============================
;; The definition of an advised function does not change until all its advice
;; (fii 3 2)
;; 5
;;
-;; @@ Specifying argument lists of subrs:
-;; ======================================
-;; The argument lists of subrs cannot be determined directly from Lisp.
-;; This means that Advice has to use `(&rest ad-subr-args)' as the
-;; argument list of the advised subr which is not very efficient. In Lemacs
-;; subr argument lists can be determined from their documentation string, in
-;; Emacs-19 this is the case for some but not all subrs. To accommodate
-;; for the cases where the argument lists cannot be determined (e.g., in a
-;; v18 Emacs) Advice comes with a specification mechanism that allows the
-;; advice programmer to tell advice what the argument list of a certain subr
-;; really is.
-;;
-;; In a v18 Emacs the following will return the &rest idiom:
-;;
-;; (ad-arglist (symbol-function 'car))
-;; (&rest ad-subr-args)
-;;
-;; To tell advice what the argument list of `car' really is we
-;; can do the following:
-;;
-;; (ad-define-subr-args 'car '(list))
-;; ((list))
-;;
-;; Now `ad-arglist' will return the proper argument list (this method is
-;; actually used by advice itself for the advised definition of `fset'):
-;;
-;; (ad-arglist (symbol-function 'car))
-;; (list)
-;;
-;; The defined argument list will be stored on the property list of the
-;; subr name symbol. When advice looks for a subr argument list it first
-;; checks for a definition on the property list, if that fails it tries
-;; to infer it from the documentation string and caches it on the property
-;; list if it was successful, otherwise `(&rest ad-subr-args)' will be used.
-;;
;; @@ Advising interactive subrs:
;; ==============================
;; For the most part there is no difference between advising functions and
If DEFINITION could be from a subr then its NAME should be
supplied to make subr arglist lookup more efficient."
(require 'help-fns)
- (cond
- ((or (ad-macro-p definition) (ad-advice-p definition))
- (help-function-arglist (cdr definition)))
- (t (help-function-arglist definition))))
-
-;; Store subr-args as `((arg1 arg2 ...))' so I can distinguish
-;; a defined empty arglist `(nil)' from an undefined arglist:
-(defmacro ad-define-subr-args (subr arglist)
- `(put ,subr 'ad-subr-arglist (list ,arglist)))
-(defmacro ad-undefine-subr-args (subr)
- `(put ,subr 'ad-subr-arglist nil))
-(defmacro ad-subr-args-defined-p (subr)
- `(get ,subr 'ad-subr-arglist))
-(defmacro ad-get-subr-args (subr)
- `(car (get ,subr 'ad-subr-arglist)))
-
-(defun ad-subr-arglist (subr-name)
- "Retrieve arglist of the subr with SUBR-NAME.
-Either use the one stored under the `ad-subr-arglist' property,
-or try to retrieve it from the docstring and cache it under
-that property, or otherwise use `(&rest ad-subr-args)'."
- (if (ad-subr-args-defined-p subr-name)
- (ad-get-subr-args subr-name)
- ;; says jwz: Should use this for Lemacs 19.8 and above:
- ;;((fboundp 'subr-min-args)
- ;; ...)
- ;; says hans: I guess what Jamie means is that I should use the values
- ;; of `subr-min-args' and `subr-max-args' to construct the subr arglist
- ;; without having to look it up via parsing the docstring, e.g.,
- ;; values 1 and 2 would suggest `(arg1 &optional arg2)' as an
- ;; argument list. However, that won't work because there is no
- ;; way to distinguish a subr with args `(a &optional b &rest c)' from
- ;; one with args `(a &rest c)' using that mechanism. Also, the argument
- ;; names from the docstring are more meaningful. Hence, I'll stick with
- ;; the old way of doing things.
- (let ((doc (or (ad-real-documentation subr-name t) "")))
- (if (not (string-match "\n\n\\((.+)\\)\\'" doc))
- ;; Signalling an error leads to bugs during bootstrapping because
- ;; the DOC file is not yet built (which is an error, BTW).
- ;; (error "The usage info is missing from the subr %s" subr-name)
- '(&rest ad-subr-args)
- (ad-define-subr-args
- subr-name
- (cdr (car (read-from-string
- (downcase (match-string 1 doc))))))
- (ad-get-subr-args subr-name)))))
+ (help-function-arglist
+ (if (or (ad-macro-p definition) (ad-advice-p definition))
+ (cdr definition)
+ definition)
+ 'preserve-names))
(defun ad-docstring (definition)
"Return the unexpanded docstring of DEFINITION."
(defun ad-definition-type (definition)
"Return symbol that describes the type of DEFINITION."
- (if (ad-macro-p definition)
- 'macro
- (if (ad-subr-p definition)
- (if (ad-special-form-p definition)
- 'special-form
- 'subr)
- (if (or (ad-lambda-p definition)
- (ad-compiled-p definition))
- 'function
- (if (ad-advice-p definition)
- 'advice)))))
+ (cond
+ ((ad-macro-p definition) 'macro)
+ ((ad-subr-p definition)
+ (if (ad-special-form-p definition)
+ 'special-form
+ 'subr))
+ ((or (ad-lambda-p definition)
+ (ad-compiled-p definition))
+ 'function)
+ ((ad-advice-p definition) 'advice)))
(defun ad-has-proper-definition (function)
"True if FUNCTION is a symbol with a proper definition.
;; Use the advice mechanism to advise `documentation' to make it
;; generate proper documentation strings for advised definitions:
-;; This makes sure we get the right arglist for `documentation'
-;; during bootstrapping.
-(ad-define-subr-args 'documentation '(function &optional raw))
-
;; @@ Starting, stopping and recovering from the advice package magic:
;; ===================================================================
(format "%S" (help-make-usage 'fn arglist))))))
;; FIXME: Move to subr.el?
-(defun help-function-arglist (def)
+(defun help-function-arglist (def &optional preserve-names)
+ "Return a formal argument list for the function DEF.
+IF PRESERVE-NAMES is non-nil, return a formal arglist that uses
+the same names as used in the original source code, when possible."
;; Handle symbols aliased to other symbols.
(if (and (symbolp def) (fboundp def)) (setq def (indirect-function def)))
;; If definition is a macro, find the function inside it.
(if (eq (car-safe def) 'macro) (setq def (cdr def)))
(cond
- ((and (byte-code-function-p def) (integerp (aref def 0)))
- (let* ((args-desc (aref def 0))
- (max (lsh args-desc -8))
- (min (logand args-desc 127))
- (rest (logand args-desc 128))
- (arglist ()))
- (dotimes (i min)
- (push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
- (when (> max min)
- (push '&optional arglist)
- (dotimes (i (- max min))
- (push (intern (concat "arg" (number-to-string (+ 1 i min))))
- arglist)))
- (unless (zerop rest) (push '&rest arglist) (push 'rest arglist))
- (nreverse arglist)))
- ((byte-code-function-p def) (aref def 0))
+ ((and (byte-code-function-p def) (listp (aref def 0))) (aref def 0))
((eq (car-safe def) 'lambda) (nth 1 def))
((eq (car-safe def) 'closure) (nth 2 def))
- ((subrp def)
- (let ((arity (subr-arity def))
- (arglist ()))
- (dotimes (i (car arity))
- (push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
- (cond
- ((not (numberp (cdr arglist)))
- (push '&rest arglist)
- (push 'rest arglist))
- ((< (car arity) (cdr arity))
- (push '&optional arglist)
- (dotimes (i (- (cdr arity) (car arity)))
- (push (intern (concat "arg" (number-to-string
- (+ 1 i (car arity)))))
- arglist))))
- (nreverse arglist)))
+ ((or (and (byte-code-function-p def) (integerp (aref def 0)))
+ (subrp def))
+ (or (when preserve-names
+ (let* ((doc (condition-case nil (documentation def) (error nil)))
+ (docargs (if doc (car (help-split-fundoc doc nil))))
+ (arglist (if docargs
+ (cdar (read-from-string (downcase docargs)))))
+ (valid t))
+ ;; Check validity.
+ (dolist (arg arglist)
+ (unless (and (symbolp arg)
+ (let ((name (symbol-name arg)))
+ (if (eq (aref name 0) ?&)
+ (memq arg '(&rest &optional))
+ (not (string-match "\\." name)))))
+ (setq valid nil)))
+ (when valid arglist)))
+ (let* ((args-desc (if (not (subrp def))
+ (aref def 0)
+ (let ((a (subr-arity def)))
+ (logior (car a)
+ (if (numberp (cdr a))
+ (lsh (cdr a) 8)
+ (lsh 1 7))))))
+ (max (lsh args-desc -8))
+ (min (logand args-desc 127))
+ (rest (logand args-desc 128))
+ (arglist ()))
+ (dotimes (i min)
+ (push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
+ (when (> max min)
+ (push '&optional arglist)
+ (dotimes (i (- max min))
+ (push (intern (concat "arg" (number-to-string (+ 1 i min))))
+ arglist)))
+ (unless (zerop rest) (push '&rest arglist) (push 'rest arglist))
+ (nreverse arglist))))
((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
"[Arg list not available until function definition is loaded.]")
(t t)))
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