Re: [boost] Scalpel: a Spirit&Wave-powered C++ source code analysis library

Subject: Re: [boost] Scalpel: a Spirit&Wave-powered C++ source code analysis library
From: Doug Gregor (doug.gregor_at_[hidden])
Date: 2010-09-07 09:50:52

On Tue, Sep 7, 2010 at 4:04 AM, Dave Abrahams <dave_at_[hidden]> wrote:
> On Sun, Sep 5, 2010 at 12:35 PM, Doug Gregor <doug.gregor_at_[hidden]> wrote:
>>
>> On Fri, Sep 3, 2010 at 3:57 PM, Dave Abrahams <dave_at_[hidden]> wrote:
>> > On Fri, Sep 3, 2010 at 6:22 PM, Florian Goujeon
>> > <florian.goujeon_at_[hidden]> wrote:
>> >> All competition is stimulating. It's beneficial for everyone. All
>> >> competitors are different from each other and aim to bring a surplus
>> >> value. As I said, Scalpel brings high homogeneity with Boost. It has
>> >> its own unique design and I also plan to endow it with round-trip
>> >> engineering capabilities.
>> >
>> >
>> > One area that scalpel could conceivably find a niche, depending on how
>> > you do it, would be in analyzing source code without seeing the full
>> > translation unit (as you might for syntax-coloring purposes).  Since
>> > CLANG is really built to be a compiler, I don't think it can do that.
>>
>> Clang does syntax coloring [*], although it does so with knowledge of
>> the full translation unit.
>
> And you know I know that ;-)

:)

>> > Of course I realize you can't always get a correct analysis if you
>> > don't see the whole TU, but especially if you're willing to do
>> > nondeterministic parsing/backtracking, you could very easily do a
>> > really good job.
>>
>> Perhaps, although I completely disagree with the "very easily" bit.
>> C++ is a ridiculously ambiguous language.
>
> Perhaps I overstated the case a *wee little* bit ;-)
>
>> Note that a compiler could implement these same techniques along its
>> recovery path to both improve diagnostics and improve support for
>> syntax coloring.
>
> Now it's my turn to be a little skeptical.  I can't imagine a compiler would
> ever try to do error recovery by throwing out all the information from
> #include files you had already processed.

Heck no! But in the absence of information (e.g., an #include couldn't
be found, or an identifier is horribly mis-typed), such approaches
could drastically improve recovery.

  - Doug