Path: utzoo!utgpu!water!watmath!uunet!mcvax!hp4nl!botter!star.cs.vu.nl!fons
From: fons@cs.vu.nl (Fons Botman)
Newsgroups: gnu.emacs.bug
Subject: Re: "format" function suggestion
Message-ID: <1534@draak.cs.vu.nl>
Date: 16 Oct 88 18:23:38 GMT
References: <8810050713.AA02552@wheat-chex.ai.mit.edu> <2977@mipos3.intel.com>
Reply-To: fons@cs.vu.nl (Fons Botman)
Distribution: gnu
Organization: VU Informatica, Amsterdam
Lines: 42

In article <2977@mipos3.intel.com> merlyn@intelob.intel.com (Randal L. Schwartz @ Stonehenge) writes:
>In article <8810050713.AA02552@wheat-chex.ai.mit.edu>, phr@WHEATIES (Paul Rubin) writes:
>| I suggest a new conversion spec, "%g" perhaps (after
>| G format in Fortran), to convert any object to its
>| printed form like prin1-to-string.
>| Also (nitpick) format's doc str does not describe %o or %x.
>
>And, as 18 people around the world are probably also typing in an
>answer to say,
>  (format "%s" val)
>is identical to
>  (format "%s" (prin1-to-string val))
>because of some very handy undocumented feature.  I found this one the
>hard way.
>-- 
>Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095

And, as 18 people around the world are probably also typing in an
answer to say,
(format "%s" (prin1-to-string 'a\ b))
"a\\ b"
(format "%s" 'a\ b)
"a b"
(format "%s" (prin1-to-string '(a\ b)))
"(a\\ b)"
(format "%s" '(a\ b))
"(a\\ b)"

So the identity mentioned is not always true.  But because of the difference
between "princ" and "print" i agree with the original poster that there should
be an extra format to distinguish between princ and prin1 conversion.
An extra format character is nicer than using prin1-to-string and
princ-to-string (also because the latter does not exist :-).

It would be nice to have the same specifiers as common lisp, i do not relate
to fortran. CL uses ~s for prin1 and ~a for princ, but then the original
definition should be switched: %s now behaves as ~a (considering the
documentation and code, not the 'feature') which would involve a lot of
replacing in old lisp code.  So the choice is to the one who implements it
(isn't it always? :-).

						The Fons