Re: [Cpptool-develop] Declaration parsing started...

[Baptiste L. <gai...@fr...>]

----- Original Message ----- 
From: Andre Baresel
To: CppTool Mailing List
Sent: Sunday, April 27, 2003 12:09 PM
Subject: Re: [Cpptool-develop] Declaration parsing started...


Baptiste Lepilleur wrote:
>>I've looked at some of the tests, and there is some 'magical' constants
appearing from nowhere for ast node range test. This makes it hard to
understand what is the range of a given node. How did you figure out their
values anyway ?

>Counting by hand is the simple answer.
E.g. "const short int" has three specifiers.
They start at 0, 6, and 12. Their lengths are 5, 5, and 3.
I will clean this up a little bit !

That would explain why most 'source' where on a single line. I'll try to see
if I can come up with a better version of SourceBuilder for testing (this
issue is not specific to your code. I remember that variable declaration
testing was quite a mess).


>>As for the test routines, they call it test driven design, or test first
design. I just made the environment to make it possible for us ;-). It was
actually the reason why I renounced to use Boost.Spirit (a generic
programming parser framework). Compile time were huge (just including the
headers in a cpp resulted in a compile time of around a minute !).

>I'm not sure yet, if the boost.spirit approach makes the parser better
understandable, since
even reading the simple examples at the spirit pages don't make me say "wow
that's it" ...
what do you think - did I miss some point which makes the "Spirit" worth for
us ?

I think it would be useful to write mini-parser (much akin to ours). The
problem is again compilation time. Who would use a date parser that take a
minute to compile ?

You also get more flexibility than in parser generator since you can define
hand coded rules and action.

Another major issue with Spirit is support for VC 6 is low. You often
stumble uppon internal compiler error, some or those, I never managed to
work around.

If we need a parser, I think PCCTS would be the best choice. It's widely
supported, and have a lot of functionnalities (it's only drawback I remember
when I looked at it a long while ago was unicode support, which is not an
issue for us). One of the nice feature it has is the ability to generate
AST, and then write a 'parser' to modify or visit that AST.

Even if it would require code generation, it would still lead to a
compile/test cycle way faster than with Boost.Spirit.

Anyway, our hand parser is fairly good and allow for very simple testing.
One of its most important property I think is the fact that it takes
advantage of the hierarchical structure of C++. This provides strong error
recovery capability (or at least, it should :-) ).

Baptiste.

>-- André