Re: Extracting parsed value from a local variable

Thanks ... I've found the solution myself ...

I actually need to use phoenix lazy actions ...
Here I wanted to create a rule that synthetized directly an
std::complex<double> ... so I was storing the real part into qi::_a and the
imaginary part into qi::_b ... and then I would have liked to write
something like

qi::_val = std::complex(qi::_a,qi::_b)

and the compiler complained ...

Actuall, using

qi::_val = boost::phoenix::construct< std::complex<double> >(qi::_a,qi::_b)

fixed the issue.

Best regards to all,
Michele

2016-10-23 19:23 GMT+02:00 Jens Kallup <[email protected]>:

> Hello Michele,
>
> try to use qi::_1 ... qi::_9  where _1 till _9 are placeholders
> for your input like double.
> The placeholder _1 is the first match, _2 the second, and so on...
>
> Jens
>
>
> On 10/23/2016 06:59 PM, Michele De Stefano wrote:
> > Dear all,
> >
> > here is my issue. I am creating a rule that happens to parse (amongst
> > several things) a double value into the qi::_a local variable. Now,
> > while staying into the same semantic action, I need to use that parsed
> > double value into another C++ instruction that requires a double value
> > as input.
> >
> > Think to this instruction as a generic
> >
> > ouput_type f(double x)
> >
> > The issue is that when I call (within the semantic action)
> >
> > f(qi::_a)
> >
> > the compiler complains that it cannot convert qi::_a into a double.
> >
> > Is there a way to extract the double value from qi::_a (or anyway from
> > any placeholder)?
> >
> > Thanks in advance.
> >
> > Best regards,
> > Michele
> >
> > --
> > Michele De Stefano
> > Linked In <http://it.linkedin.com/in/micheledestefano>
> > mds-utils: a general purpose Open Source library
> > <http://sourceforge.net/projects/mds-utils/>
> > Personal Web Site <https://sites.google.com/site/micdestefano/>
> >
> >
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-- 
Michele De Stefano
Linked In <http://it.linkedin.com/in/micheledestefano>
mds-utils: a general purpose Open Source library
<http://sourceforge.net/projects/mds-utils/>
Personal Web Site <https://sites.google.com/site/micdestefano/>

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