chilon Code

#ifndef CHILON_PARSER_CHOICE_HPP
#define CHILON_PARSER_CHOICE_HPP

#include <chilon/parser/parse.hpp>
#include <chilon/parser/detail/choice.hpp>

#include <chilon/meta/flatten.hpp>

namespace chilon { namespace parser {

/**
 * Ordered choice (| in grammar)
 */
template <class... Matches>
struct choice;

template <>
struct choice<> {
    template <class Stream>
    inline static bool skip(Stream& stream) {
        return false;
    }

    template <class Stream>
    inline static bool match(Stream const& stream) {
        return false;
    }
};

template <class Head, class... Tail>
struct choice<Head, Tail...>
  : parse_base<detail::parse_choice<Head, Tail...>>
{
    template <class Stream>
    inline static bool skip(Stream& stream) {
        return Head::skip(stream) || choice<Tail...>::skip(stream);
    }

    template <class Stream>
    inline static bool match(Stream const& stream) {
        return Head::match(stream) || choice<Tail...>::match(stream);
    }
};

template <class... T>
struct parse<detail::parse_choice<T...>> : detail::parse_choice<T...> {};

} }
#endif