From: Alan Mackenzie <acm@muc.de>
To: npostavs@users.sourceforge.net
Cc: Arash <pbqbqp@gmail.com>, Andreas Schwab <schwab@linux-m68k.org>,
24195@debbugs.gnu.org
Subject: bug#24195: 25.0.95; Wrong indentation after a 'less < than' comparison (c++-mode)
Date: Mon, 22 Aug 2016 11:08:02 +0000 [thread overview]
Message-ID: <20160822110802.GB2571@acm.fritz.box> (raw)
In-Reply-To: <87inuyuvip.fsf@users.sourceforge.net>
Hello, Noam.
On Thu, Aug 18, 2016 at 08:11:26AM -0400, npostavs@users.sourceforge.net wrote:
> Andreas Schwab <schwab@linux-m68k.org> writes:
> > On Aug 12 2016, Noam Postavsky <npostavs@users.sourceforge.net> wrote:
> >> On Thu, Aug 11, 2016 at 8:14 AM, Alan Mackenzie <acm@muc.de> wrote:
> >>> Yes. In the line "k() < l() &&", the "<" is being recognised as a
> >>> template opener.
> >> Is it possible to say that "<" can't be a template opener when it
> >> comes after a close paren? (I can't think of a case in C++ where that
> >> would fail, though I'm not 100% certain there isn't one)
> > operator()<foo>
> So could we say "<" can't be a template opener when it comes after a
> close paren except for the close paren of "operator()"?
We could, but I can't see it helping very much (though it might help a
little bit).
There are probably quite a lot of special cases like that where it is
possible to say for sure that the "<" does/doesn't introduce a template
construct. But that will leave a lot of ambiguous cases. The more we
try to analyse these, the closer we get to building a compiler inside CC
Mode. For example, the example given might have been "k < l() && ....",
leaving no syntactic clues about the templateicity of "<".
Analysing the C++ syntax to determine these determinable cases would be
a lot of work, and it would be a lot of work to implement it, too.
The C++ standards people haven't thought it worthwhile to preserve
unambigious syntax in their language, so there is no way CC Mode can get
it right every time.
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2016-08-22 11:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-10 9:38 bug#24195: 25.0.95; Wrong indentation after a 'less < than' comparison (c++-mode) Arash
2016-08-10 22:07 ` Robert Cochran
2016-08-11 12:14 ` Alan Mackenzie
2016-08-12 15:26 ` Noam Postavsky
2016-08-12 16:56 ` Andreas Schwab
2016-08-18 12:11 ` npostavs
2016-08-22 11:08 ` Alan Mackenzie [this message]
2016-08-25 1:24 ` npostavs
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