RE: [boost] Re: Interest in a Recursive Descent Parsing Library

From: Hartmut Kaiser (hartmutkaiser_at_[hidden])
Date: 2004-12-25 14:55:12

christopher diggins wrote:

> I think this does a good job of illustrating the difference 
> between Spirit 
> and YARD. Spirit would require the following code, for the grammar 
> production written above using YARD:
> 
>     rule<> rule_overall =
>             switch_p
>             [
>                 case_p<'a'>(parser_a),
>                 case_p<'b'>(parser_b),
>                 case_p<'c'>(parser_b),
>                 case_p<'d'>(parser_b),
>                 default_p(parser_default)
>             ]
>         ;
> 
> With Spirit there is an arbitrary upper bound on the number of case 
> statements, which defaults to 3(!?). I would think that it is 
> safe to say 
> that the YARD parser is easier to use, and has fewer 
> arbitrary constraints 
> *BUT* does not provide dynamic rule expressions, and is more verbose.

What's the problem with the default value?

Regards Hartmut