| /*============================================================================= |
| Copyright (c) 2001-2010 Hartmut Kaiser |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| =============================================================================*/ |
| #if !defined(SPIRIT_ALTERNATIVE_FUNCTION_APRIL_23_2007_1046AM) |
| #define SPIRIT_ALTERNATIVE_FUNCTION_APRIL_23_2007_1046AM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/spirit/home/qi/domain.hpp> |
| #include <boost/spirit/home/qi/detail/assign_to.hpp> |
| #include <boost/spirit/home/support/unused.hpp> |
| #include <boost/spirit/home/qi/detail/attributes.hpp> |
| #include <boost/variant.hpp> |
| #include <boost/mpl/bool.hpp> |
| |
| namespace boost { namespace spirit { namespace qi { namespace detail |
| { |
| template <typename Iterator, typename Context, typename Skipper, |
| typename Attribute> |
| struct alternative_function |
| { |
| alternative_function( |
| Iterator& first, Iterator const& last, Context& context, |
| Skipper const& skipper, Attribute& attr) |
| : first(first), last(last), context(context), skipper(skipper), |
| attr(attr) |
| { |
| } |
| |
| template <typename Component> |
| bool call(Component const& component, mpl::true_) const |
| { |
| // if Attribute is not a variant, then pass it as-is |
| return component.parse(first, last, context, skipper, attr); |
| } |
| |
| template <typename Component> |
| bool call(Component const& component, mpl::false_) const |
| { |
| // if Attribute is a variant or optional, then create an |
| // attribute for the Component with its expected type. |
| typename traits::attribute_of<Component, Context, Iterator>::type val; |
| if (component.parse(first, last, context, skipper, val)) |
| { |
| traits::assign_to(val, attr); |
| return true; |
| } |
| return false; |
| } |
| |
| template <typename Component> |
| bool operator()(Component const& component) const |
| { |
| // return true if the parser succeeds |
| return call(component, |
| mpl::and_< |
| spirit::traits::not_is_variant<Attribute, qi::domain>, |
| spirit::traits::not_is_optional<Attribute, qi::domain> |
| >()); |
| } |
| |
| Iterator& first; |
| Iterator const& last; |
| Context& context; |
| Skipper const& skipper; |
| Attribute& attr; |
| |
| private: |
| // silence MSVC warning C4512: assignment operator could not be generated |
| alternative_function& operator= (alternative_function const&); |
| }; |
| |
| template <typename Iterator, typename Context, typename Skipper> |
| struct alternative_function<Iterator, Context, Skipper, unused_type const> |
| { |
| alternative_function( |
| Iterator& first, Iterator const& last, Context& context, |
| Skipper const& skipper, unused_type) |
| : first(first), last(last), context(context), skipper(skipper) |
| { |
| } |
| |
| template <typename Component> |
| bool operator()(Component const& component) |
| { |
| // return true if the parser succeeds |
| return component.parse(first, last, context, skipper, |
| unused); |
| } |
| |
| Iterator& first; |
| Iterator const& last; |
| Context& context; |
| Skipper const& skipper; |
| |
| private: |
| // silence MSVC warning C4512: assignment operator could not be generated |
| alternative_function& operator= (alternative_function const&); |
| }; |
| |
| }}}} |
| |
| #endif |