Re: Parser rewritting

[Chris Moller <cmoller at redhat dot com>]

On 03/30/10 14:46, Sergio Durigan Junior wrote:
> Hello!
>
> As you may have noticed, in the last Archer meeting I brought a topic into
> discussion: the rewritting of the GDB's parser.  The current parser is written
> using Bison, and unfortunately it is insufficient to satisfy our current
> needs, especially for C++ productions.
>
> With that in mind, Tom asked me to start this discussion in the mailing-list
> to see what you think about it.  We decided to send an e-mail to the archer
> list at first; this topic will eventually be discussed at the gdb list as
> well.
>    

A lot of years ago I wrote a fairly elaborate parser using 
antlr--definitely a cool tool and I recommend you consider it.  It's a 
predicated LL(*) parser generator--the "predicated" bit making it 
possible, among other things, to handle the context-dependent bits of  
C/C++ grammar.

Just as an example, I've attached a rudimentary antlr grammar that 
parses a subset of C/C++ decls--if you look, you'll see that the rules 
look a lot like the specifications in the C++, and in fact started out 
as a cut'n'paste of those specs.  Also, if you look in the grammar for 
"is_cpp," you can see how rule predicates can be used to have the parser 
do different things depending on circumstances.

Anyway, it's probably worth considering.

(In addition to the .g file attached, I wrote a couple other .c and .h 
files that make it all work.  I'll make them available if anyone wants him.)

Chris

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