#ifndef TERMINAL_HPP_
#define TERMINAL_HPP_

#include "symbol.hpp"

template< char ... >
class terminal;
template< char Element>
class terminal< Element >
    : public symbol
{
public:
    template< class CharType >
    constexpr terminal( const_string< CharType > str , std::size_t begin = 0 )
        : symbol
        (
            begin < str.size() ?
                str[ begin ] == Element ?
                begin + 1 :
                invalid_index
            : invalid_index
        )
    {
    }
};


constexpr bool const_strcomp( const_string< char > a , std::size_t pos_a , const_string< char > b , std::size_t pos_b )
{
    return
    ( pos_a >= a.size() || pos_b >= b.size() ) ?
        true :
        ( a[ pos_a ] == b[ pos_b ] ) ?
            const_strcomp( a , pos_a + 1 , b , pos_b + 1 ) :
            false;
}

#define DEF_TERMINAL( TerminalName , StringLiteral ) \
class TerminalName \
    : public symbol \
{ \
public: \
    template< class CharType > \
    constexpr TerminalName( const_string< CharType > str , std::size_t begin = 0 ) \
        : symbol \
        ( \
            begin + const_string< char >( StringLiteral ).size() > str.size() ? \
                invalid_index : \
                const_strcomp( str , begin , const_string< char >( StringLiteral ) , 0 ) ? \
                    begin + const_string< char >( StringLiteral ).size() : \
                    invalid_index \
        ) \
    { \
    } \
};

#endif