From: Peter Bex <Peter.Bex@xs4all.nl>
To: Mark H Weaver <mhw@netris.org>
Cc: Ian Price <ianprice90@googlemail.com>, 11887@debbugs.gnu.org
Subject: bug#11887: string->number edge cases
Date: Tue, 5 Mar 2013 20:14:26 +0100 [thread overview]
Message-ID: <20130305191426.GJ4379@frohike.xs4all.nl> (raw)
In-Reply-To: <878v61ekh4.fsf@tines.lan>
On Tue, Mar 05, 2013 at 02:04:55PM -0500, Mark H Weaver wrote:
> FYI, I produced a simple patch a while back to fix this (see below), but
> it had an interesting side effect: it caused the reader to read things
> like "3/0" and "4+3/0i" as symbols. More generally, anything for which
> 'scm_string_to_number' returns false is treated as a symbol by 'read'.
I think this is simple and at least internally consistent. Several
Schemes assume something like 1/0 is a symbol; Chicken does this as
well, with the numbers egg loaded, so does Gambit.
Raising an error is also acceptable. According to the lexical syntax
1/0 *is* a valid number, so you could argue that it *must* parse as
a number, which is impossible so an error should occur.
This is also related to how string->number deals with it; if it
returns #f it is essentially saying "this is not valid numerical syntax"
and should fail to parse as a number. Not raising an exception on
(string->number "1/0) but raising an exception on
(with-input-from-string "1/0" read) is a bit odd, I'd say.
Cheers,
Peter
--
http://www.more-magic.net
next prev parent reply other threads:[~2013-03-05 19:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-09 12:29 bug#11887: string->number edge cases Ian Price
2013-03-05 14:49 ` Andy Wingo
2013-03-05 19:04 ` Mark H Weaver
2013-03-05 19:14 ` Peter Bex [this message]
2013-03-06 18:11 ` Mark H Weaver
2013-03-06 18:15 ` bug#11887: [PATCH] Improve standards conformance of string->number (was Re: bug#11887: string->number edge cases) Mark H Weaver
2013-03-07 20:47 ` Mark H Weaver
2013-03-05 19:06 ` bug#11887: string->number edge cases Peter Bex
[not found] <mailman.1167569.1362509701.854.bug-guile@gnu.org>
2013-03-05 20:33 ` Daniel Llorens
2013-03-06 16:55 ` Mark H Weaver
2013-03-06 17:11 ` Daniel Llorens
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