#ifndef NUMBER_HPP_
#define NUMBER_HPP_

#include "terminal.hpp"
#include "alt.hpp"
#include "opt.hpp"
#include "concat.hpp"



typedef alt
<
    terminal< '0' > ,
    terminal< '1' > ,
    terminal< '2' > ,
    terminal< '3' > ,
    terminal< '4' > ,
    terminal< '5' > ,
    terminal< '6' > ,
    terminal< '7' > ,
    terminal< '8' > ,
    terminal< '9' >
> digit_09;


struct digit_get_val
{
    typedef unsigned int result_type;
    constexpr unsigned int null()
    {
        return 10;
    }
    template< char C >
    constexpr unsigned int operator()( terminal< C > )
    {
        return C - 48;
    }
};



struct sequence_09
    : concat
    <
        digit_09 ,
        opt< sequence_09 >
    >
{
    template< class ...ArgTypes >
    constexpr sequence_09( ArgTypes ...args )
        : concat
        <
            digit_09 ,
            opt< sequence_09 >
        >( args... )
    {
    }
    constexpr unsigned int significance()
    {
        return
        get< 1 >() ?
            10 * get< 1 >().get().significance() :
            1;
    }
    constexpr unsigned int eval()
    {
        return get< 0 >().apply_visitor( digit_get_val() ) * significance() +
            (
                get< 1 >() ?
                    get< 1 >().get().eval() :
                    0
            );
    }
};

typedef sequence_09 number;

#endif