Re: [Boost-users] [Proto] Lazy function test

Subject: Re: [Boost-users] [Proto] Lazy function test
From: Noman javed (noman_bwp_at_[hidden])
Date: 2010-04-30 07:22:18

joel falcou <joel.falcou <at> lri.fr> writes:

> 
> You need to chaneg your gramamr so it match a pow_ tag and a terminal<pow_>
> 

Here is my function and the grammar

struct INC_TAG
{
        typedef double result_type;
        double operator()(double  no) const
        {
                return 1.0+no;
        }
};

template<typename Arg>
typename proto::result_of::make_expr<
   proto::tag::function
  ,INC_TAG
  ,Arg
 >::type
inc_(Arg const &arg)
{
   return proto::make_expr<proto::tag::function>(INC_TAG(), arg);
}

struct calculator_grammar
  : proto::or_<
        proto::plus< calculator_grammar, calculator_grammar >
      , proto::minus< calculator_grammar, calculator_grammar >
      , proto::multiplies< calculator_grammar, calculator_grammar >
      , proto::divides< calculator_grammar, calculator_grammar >
      , proto::function<proto::terminal<INC_TAG>, calculator_grammar >	
      , proto::terminal< proto::_ >
    >
{};

double d = inc_(_1)(2);  // fine
double d = inc_(2); // don't work
Even though i have added the following in the grammar

proto::function<proto::terminal<INC_TAG>, calculator_grammar >