Re: [Boost-users] [xpressive] Calling a function with captured text as a parameter from a rule action

Subject: Re: [Boost-users] [xpressive] Calling a function with captured text as a parameter from a rule action
From: Eric Niebler (eric_at_[hidden])
Date: 2009-10-01 11:26:39

Hi Ami,

Some answers are inline below... You were very close.

Ami Ganguli wrote:
> Here's the important bits of my code:
> 
> My function object:
> 
>   struct append_element_impl
>   {
>      typedef void result_type;
>      void operator()(std::string& text) const
-----------------------^^^^^^^^^^^^^^^^^

Make this std::string const &. Note the const.

>      {
>         std::cout << "appending " << text;
>      }
>   };
>   function<append_element_impl>::type const append_element = {{}};
> 
> The part of the parser that calls the function:
> 
>    h1 = "=" >> +blank >> * (s1= ~_ln) >> eol
>          [append_element(as<std::string>(s1))];
---------------------------^^^^^^^^^^^^^^^

as<std::string> should not be necessary.

<snip>
>     /usr/local/include/boost/proto/context/default.hpp:357: error:
> return-statement with a value, in function returning 'void'

This one is a little strange. I assume you're using gcc. It's possible 
that once the other errors are corrected, this one will go away. If not, 
change the return type of append_element_impl to int, and return just 0.

Hope that helps,

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com