Re: Any interest for a parser class?

From: rogeeff (rogeeff_at_[hidden])
Date: 2002-01-17 02:25:28

--- In boost_at_y..., "joel de guzman" <djowel_at_g...> wrote:
> 
[...]

> 
> > > I would implement the same logic in 2-3 lines using tokenizer 
or 
> > > regexp. Something like this:
> > 
> > > token_iterator it( str, " \t,()" );
                                    ^forgot parenthesis

> > > 
> > > real      = lexical_cast<double>( *it++ );
> > > imaginary = lexical_cast<double>( *it );
> 
> It's not the same! Dan's one-liner could parse complex numbers of 
the
> form:
> 
>      r or (r) or (r, i)
> 

So do i. I just forget ot add parenthesis in the delimeters list.

> Now rewrite that again using tokenizer. Then when you are done,
> try parsing a vector of comma separated complex numbers where 
> the first number parsed is the size of the vector. Of the form:   
> 
>     N { c0, c1, c2, .... cN }
> 
> With Spirit, this is still a one-liner. 

I am not that familiar with regexp syntax but It should also be 
possible to express with one line definition (and if you would talk 
with some of the boost::format guys they would explain to you why 
they regexp implementation: parsing rule can be exported into the 
resource file and changed dynamically)
> 
> Regards,
> --Joel

Regards,
Gennadiy.