Re: [boost] Re: [ANN] Spirit C++ parser framework

From: joel de guzman (joel_at_[hidden])
Date: 2001-05-22 06:10:20

----- Original Message ----- 
From: "Vesa Karvonen" :

>         // Generates the parser from the grammar expression
>         Parser parser = re
>                       | '(' + re + ')'
>                       | '(' + re + ',' + im + ')'
>                       ;

[snip]

> > I would like to see working implementation that can handle syntax that
> you've
> > given a few lines above.
> 
> Me, too!
> 

[snip]

Consider it done. I'll add that capability or a variation
into the framework. The open-ended nature of
spirit makes that trivial to do:

Something like:

    FloatVar re, im;
    Rule<> r = re | '(' >> re >> ')' | '(' >> re >> ',' >> im >> ')';

or perhaps (better yet?):

    Rule<> r = re | '(' >> re !(',' >> im) >> ')';

where !a means a is optional.
 
now you can:

  if (r.Parse(iter))
 {
     float f1 = re;
     float f2 = im;
 }

** Rule is paramaterized by the character type, defaults to char.
** one (but not both) literal is OK in a binary expression. I used
 clpar, minus etc. just to make things clear.

I quote:

For binary operators, one of the operands (but not both [N7]) 
may be a char, wchar_t, char const* or wchar_t const*. Examples:

    a | 'x';
    a - "Hello World";

Thanks for your comments....

Later,
Joel de Guzman