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From: jbw@bucsf.bu.edu (Joe Wells)
Newsgroups: gnu.emacs.bug
Subject: Re: redundent arg computation
Message-ID: <38168@bu-cs.BU.EDU>
Date: 15 Sep 89 02:16:22 GMT
References: <8909150058.AA09492@life.ai.mit.edu>
Sender: daemon@bu-cs.BU.EDU
Distribution: gnu
Organization: Boston University Computer Science Department
Lines: 22
In-reply-to: gildea@BBN.COM's message of 15 Sep 89 00:56:17 GMT

In article <8909150058.AA09492@life.ai.mit.edu> gildea@BBN.COM (Stephen Gildea) writes:

   Some of the functions in lisp.el -- forward-sexp, backward-sexp,
   forward-list, and backward-list -- specify "(interactive "p")" but then
   do "(or arg (setq arg 1))", which isn't necessary.

This allows these functions to be used from Lisp code like this:

  (forward-sexp)

as shorthand for this:

  (forward-sexp 1)

The arguments of these functions are declared using the &optional keyword,
which directs lisp to fill in the parameters with nil, if arguments are
not supplied.

--
Joe Wells <jbw@bucsf.bu.edu>
jbw%bucsf.bu.edu@bu-it.bu.edu
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