From: dewar@gnat.com
To: pfk@fuchs.offl.uni-jena.de, zack@codesourcery.com
Cc: gcc@gcc.gnu.org
Subject: Re: Proposal
Date: Wed, 19 Sep 2001 00:06:00 -0000 [thread overview]
Message-ID: <20010919070548.B0DC9F2B64@nile.gnat.com> (raw)
<<You should investigate the rules for numeric syntax in languages
which already have this notation, such as Ada and Perl.
>>
In Ada, underscores can only be used to separate digits, and the extension
is thus a simple one from a syntactic definition point of view. The actual
excerpt from the Ada grammar is as follows:
2 decimal_literal ::= numeral [.numeral] [exponent]
3 numeral ::= digit {[underline] digit}
4 exponent ::= E [+] numeral | E - numeral
I don't see any language or definition issue in introducing exactly this
same restricted form into C
16777216_UL
16777216U_L
0._1234
0x_1234
12.34_e+56
12.34e_+56
All these should be illegal if the above approach is followed, and I think
that is the right choice. The only legitimate use of the underscore is to
separate digits in a long sequence of digits.
next reply other threads:[~2001-09-19 0:06 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-19 0:06 dewar [this message]
-- strict thread matches above, loose matches on Subject: below --
2013-06-26 17:47 Proposal Barrister David Lopez Esq
2013-06-26 17:41 Proposal Barrister David Lopez Esq
2013-06-26 18:15 ` Proposal Paolo Carlini
2013-06-26 18:40 ` Proposal Daniel Santos
2012-09-03 18:35 Proposal Afeez Basit
2012-09-03 15:16 Proposal Afeez Basit
2001-09-19 2:44 Proposal dewar
2001-09-19 2:34 Proposal dewar
2001-09-18 12:30 Proposal dewar
2001-09-18 23:01 ` Proposal Zack Weinberg
2001-09-18 9:32 Proposal dewar
2001-09-17 8:55 Proposal Thomas R. Truscott
2001-09-15 11:45 Proposal Frank Klemm
2001-09-15 12:15 ` Proposal Gerald Pfeifer
2001-09-17 16:00 ` Proposal Neil Booth
2001-09-18 2:30 ` Proposal Joseph S. Myers
2001-09-18 10:21 ` Proposal Zack Weinberg
2001-09-18 11:14 ` Proposal Joseph S. Myers
2001-09-18 22:20 ` Proposal Zack Weinberg
2001-09-19 1:14 ` Proposal Joseph S. Myers
2001-09-18 12:23 ` Proposal Frank Klemm
2001-09-18 22:37 ` Proposal Zack Weinberg
2001-09-19 0:02 ` Proposal Neil Booth
2001-09-19 2:23 ` Proposal Tim Hollebeek
2001-09-19 2:41 ` Proposal Richard Earnshaw
2001-09-19 13:38 ` Proposal Joe Buck
2001-09-18 15:35 ` Proposal Robert Lipe
2001-09-18 16:59 ` Proposal Russ Allbery
2001-09-20 11:17 ` Proposal Kai Henningsen
2001-09-20 12:34 ` Proposal Russ Allbery
2001-09-18 9:48 ` Proposal Frank Klemm
2001-09-18 11:06 ` Proposal Neil Booth
2001-09-18 11:37 ` Proposal Kevin Handy
2001-09-18 15:48 ` Proposal Neil Booth
2001-09-18 15:55 ` Proposal Toon Moene
2001-09-27 5:39 ` Proposal Alexandre Oliva
2001-09-27 7:09 ` Proposal Frank Klemm
2001-09-27 16:22 ` Proposal Zack Weinberg
2001-09-29 15:45 ` Proposal Frank Klemm
2001-09-30 9:35 ` Proposal Zack Weinberg
2001-09-27 16:36 ` Proposal Neil Booth
2001-09-29 15:45 ` Proposal Frank Klemm
2001-09-29 17:22 ` Proposal Daniel Jacobowitz
2001-10-03 3:52 ` Proposal Fergus Henderson
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