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From: thomas%spline.uucp@utah-gr.UUCP (Spencer W. Thomas)
Newsgroups: comp.emacs
Subject: Re: Improvement Suggestion for Gnu Emacs online documentation
Message-ID: <2127@utah-gr.UUCP>
Date: Fri, 28-Aug-87 13:31:35 EDT
Article-I.D.: utah-gr.2127
Posted: Fri Aug 28 13:31:35 1987
Date-Received: Sun, 30-Aug-87 01:44:04 EDT
References: <8708192128.AA02674@ELI.CS.YALE.EDU> <2697@bobkat.UUCP>
Sender: news@utah-gr.UUCP
Reply-To: thomas%spline.UUCP@utah-gr.UUCP (Spencer W. Thomas)
Organization: Univ of Utah CS Dept
Lines: 30

[A suggestion was made that the documentation should indicate whether
a particular function is implemented in C or not]

  This is certainly not appropriate for the online user documentation.
For the (mostly non-existent) programmer's manual, maybe.  Anyway, for
now, you can always use symbol-function to give you this indication:

(symbol-function 'forward-char)
#<subr forward-char>
(symbol-function 'next-line)
(lambda (arg) 125274 (interactive "p") (byte-code
"BCU*

nil 1 forward-line 10 line-move] 4))

Here is a little function that will do the work for you:

(defun c-function-p (sym)
  "Returns T if the function named by SYM is implemented in C."
  (interactive "aFunction: ")
  (if (interactive-p)
      (message "Function %s is%s defined in C." sym 
	       (if (not (listp (symbol-function sym))) "" " not"))
    (not (listp (symbol-function sym)))))

(c-function-p 'forward-char)
t
(c-function-p 'next-line)
nil
=Spencer   ({ihnp4,decvax}!utah-cs!thomas, thomas@cs.utah.edu)