Re: parsing ISO C++(1998/2003)

"Torben "Ęgidius" Mogensen" <torbenm@app-7.diku.dk> wrote in message
> "Aaron Gray" <ang.usenet@gmail.com> writes:
>
>
>> What would be a good tool is something that takes an ambiguous
>> grammar an generates a GLR grammar. I am not sure whether this
>> problem is decidable or not though.
>
> GLR parsers are able to parse ambiguous grammars, so this is trivially
> true.


The programmer has to program the points at which the GLR actually branches.


> What you need, however, is a way to choose which one of the
> many parse trees that the GLR parser gives you that you want, and I
> can see no way of getting this automatically -- unless you can
> formally specify disambiguation rules (such as operator precedence
> rules). Operator precendence rules are insufficient to make the C++
> grammar unambiguous, though.


It's a case of transforming (or pruning) the AST. This may be done by
transformation rules but probably better done by bespoke code for
efficiency reasons.


Aaron

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