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Re: When did K&R function declarations become obsolete?

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"Ben Bacarisse" <ben.usenet@bsb.me.uk> wrote in message 
news:0.fbfbfabd314735c90fbc.20111213194943GMT.87wra0l0a0.fsf@bsb.me.uk...
> "Scott Fluhrer" <sfluhrer@ix.netcom.com> writes:
>
>> "Ben Bacarisse" <ben.usenet@bsb.me.uk> wrote in message
>> news:0.bfa81e69542c0fc48709.20111213135813GMT.87borcmv4a.fsf@bsb.me.uk...
>>> Alan Mackenzie <acm@muc.de> writes:
>>>
>>>> Ben Bacarisse <ben.usenet@bsb.me.uk> wrote:
>>>>> Alan Mackenzie <acm@muc.de> writes:
>>>>> <snip>
>>>>>>                                           It's just that there is a
>>>>>> new option to disable K&R header parsing - this parsing can be
>>>>>> inordinately slow, for example when there are long sequences of
>>>>>> variable
>>>>>> declarations (which might be K&R parameter specifications).  It's a
>>>>>> shame
>>>>>> to impose this performance penalty on everybody, just because of some
>>>>>> obsolete construct which "nobody" uses any more.
>>>>
>>>>> Can you expand on this?  I can't see why it would be particularly 
>>>>> slow.
>>>>> Your description hints at some hard to resolve ambiguity with 
>>>>> old-style
>>>>> function declarations.
>>>>
>>>> Certainly.  There's a lisp function c-in-knr-argdecl which determines
>>>> whether the current position is inside a K&R section.  It basically
>>>> searches back over (what look like) variable declarations till it comes
>>>> to a ')' which isn't followed by a ';'.  It then performs some extra
>>>> checks.  If there is no such ')' but large numbers of variable
>>>> declarations, c-in-knr-argdecl could be searching an awful long way. 
>>>> To
>>>> counteract this danger, there is an arbitrary limit (20) on the number 
>>>> of
>>>> parameters.  Even with this limit, things can get a bit sluggish.
>>>
>>> Sorry, I'd forgotten the context -- I though you were saying that it was
>>> slow to parse in the normal sense.
>>
>> I suspect that this is the problem; the compiler sees the tokens:
>>
>> foo(a, b, c, d, e, f)
>>
>> Is this a call to the function foo, or is this the start of a K&R 
>> definition
>> of the function 'foo'?
>
> You use of "the problem" is confusing.  Alan Mackenzie explained what the
> problem was that he and I were talking about, and it's not to do with
> compiling but parsing inside an editor.

Oops, I missed that; I assumed he was talking about parsing within a 
compiler.  Sorry...

-- 
poncho

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When did K&R function declarations become obsolete? Alan Mackenzie <acm@muc.de> - 2011-12-10 18:23 +0000
  Re: When did K&R function declarations become obsolete? Kaz Kylheku <kaz@kylheku.com> - 2011-12-10 18:41 +0000
  Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-10 10:40 -0800
    Re: When did K&R function declarations become obsolete? Ian Collins <ian-news@hotmail.com> - 2011-12-11 07:49 +1300
    Re: When did K&R function declarations become obsolete? Ben Pfaff <blp@cs.stanford.edu> - 2011-12-10 10:49 -0800
  Re: When did K&R function declarations become obsolete? jt@toerring.de (Jens Thoms Toerring) - 2011-12-10 21:16 +0000
    Re: When did K&R function declarations become obsolete? Alan Mackenzie <acm@muc.de> - 2011-12-12 11:29 +0000
      Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-12 03:49 -0800
      Re: When did K&R function declarations become obsolete? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-12 15:04 +0000
        Re: When did K&R function declarations become obsolete? Alan Mackenzie <acm@muc.de> - 2011-12-13 10:42 +0000
          Re: When did K&R function declarations become obsolete? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-13 13:58 +0000
            Re: When did K&R function declarations become obsolete? "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2011-12-13 10:17 -0500
              Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-13 12:04 -0600
                Re: When did K&R function declarations become obsolete? Kaz Kylheku <kaz@kylheku.com> - 2011-12-13 18:17 +0000
                Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-13 15:17 -0600
                Re: When did K&R function declarations become obsolete? Kaz Kylheku <kaz@kylheku.com> - 2011-12-13 21:46 +0000
                Re: When did K&R function declarations become obsolete? Seebs <usenet-nospam@seebs.net> - 2011-12-13 22:04 +0000
                Re: When did K&R function declarations become obsolete? jgk@panix.com (Joe keane) - 2011-12-13 23:07 +0000
                Re: When did K&R function declarations become obsolete? Seebs <usenet-nospam@seebs.net> - 2011-12-13 23:23 +0000
                Re: When did K&R function declarations become obsolete? Kaz Kylheku <kaz@kylheku.com> - 2011-12-14 00:26 +0000
                Re: When did K&R function declarations become obsolete? blp@cs.stanford.edu (Ben Pfaff) - 2011-12-13 15:22 -0800
                Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-13 15:27 -0800
                Re: When did K&R function declarations become obsolete? Alan Mackenzie <acm@muc.de> - 2011-12-14 09:33 +0000
              Re: When did K&R function declarations become obsolete? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-13 19:49 +0000
                Re: When did K&R function declarations become obsolete? "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2011-12-13 14:54 -0500
    Re: When did K&R function declarations become obsolete? luser- -droog <mijoryx@yahoo.com> - 2011-12-20 02:28 -0800
  Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-10 13:48 -0800
    Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-10 21:48 -0800
  Re: When did K&R function declarations become obsolete? Ralph Spitzner <rasp@spitzner.org> - 2011-12-11 04:16 +0100
    Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-10 21:54 -0800
  Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-10 22:27 -0600
    Re: When did K&R function declarations become obsolete? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-11 12:56 +0000
      Re: When did K&R function declarations become obsolete? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-11 09:11 -0500
        Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-11 21:40 -0600
          Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-12 00:05 -0800
            Re: When did K&R function declarations become obsolete? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-12 15:00 +0000
              Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-12 07:18 -0800
                Re: When did K&R function declarations become obsolete? Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-13 00:55 -0800
                Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-13 07:50 -0800
              Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-12 11:15 -0600
            Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-12 11:17 -0600
              Re: When did K&R function declarations become obsolete? jgk@panix.com (Joe keane) - 2011-12-12 21:57 +0000
                Re: When did K&R function declarations become obsolete? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-12 18:15 -0500
      Re: When did K&R function declarations become obsolete? ralph <nt_consulting64@yahoo.net> - 2011-12-11 15:10 -0600
  Re: When did K&R function declarations become obsolete? James Kuyper <jameskuyper@verizon.net> - 2011-12-11 09:17 -0500
    Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-11 06:53 -0800
      Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-12 00:08 -0800
    Re: When did K&R function declarations become obsolete? Alan Mackenzie <acm@muc.de> - 2011-12-12 11:59 +0000
      Re: When did K&R function declarations become obsolete? James Kuyper <jameskuyper@verizon.net> - 2011-12-12 07:47 -0500
        Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-12 11:59 -0800
          Re: When did K&R function declarations become obsolete? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-12 18:17 -0500
            Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-12 15:43 -0800
      Re: When did K&R function declarations become obsolete? André Gillibert <MetaEntropy.removeThis@gmail.com> - 2011-12-12 13:49 +0100
        Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-12 05:25 -0800
          Re: When did K&R function declarations become obsolete? André Gillibert <MetaEntropy.removeThis@gmail.com> - 2011-12-12 14:35 +0100
      Re: When did K&R function declarations become obsolete? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-12 15:21 +0000
  Re: When did K&R function declarations become obsolete? Jonathan Leffler <jleffler@earthlink.net> - 2011-12-13 22:19 -0800
    Re: When did K&R function declarations become obsolete? Keith Thompson <kst-u@mib.org> - 2011-12-14 02:54 -0800
      Re: When did K&R function declarations become obsolete? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-14 13:17 -0800

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