// Copyright (c) 2001-2011 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_QI_ATTR_CAST_SEP_26_2009_0735PM) | |
#define SPIRIT_QI_ATTR_CAST_SEP_26_2009_0735PM | |
#if defined(_MSC_VER) | |
#pragma once | |
#endif | |
#include <boost/spirit/home/qi/meta_compiler.hpp> | |
#include <boost/spirit/home/qi/parser.hpp> | |
#include <boost/spirit/home/qi/domain.hpp> | |
#include <boost/spirit/home/support/unused.hpp> | |
#include <boost/spirit/home/support/info.hpp> | |
#include <boost/spirit/home/support/common_terminals.hpp> | |
#include <boost/spirit/home/qi/detail/attributes.hpp> | |
#include <boost/spirit/home/support/auxiliary/attr_cast.hpp> | |
namespace boost { namespace spirit | |
{ | |
/////////////////////////////////////////////////////////////////////////// | |
// Enablers | |
/////////////////////////////////////////////////////////////////////////// | |
// enables attr_cast<>() pseudo parser | |
template <typename Expr, typename Exposed, typename Transformed> | |
struct use_terminal<qi::domain | |
, tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed> > | |
: mpl::true_ {}; | |
}} | |
namespace boost { namespace spirit { namespace qi | |
{ | |
using spirit::attr_cast; | |
/////////////////////////////////////////////////////////////////////////// | |
// attr_cast_parser consumes the attribute of subject generator without | |
// generating anything | |
/////////////////////////////////////////////////////////////////////////// | |
template <typename Exposed, typename Transformed, typename Subject> | |
struct attr_cast_parser | |
: unary_parser<attr_cast_parser<Exposed, Transformed, Subject> > | |
{ | |
typedef typename result_of::compile<qi::domain, Subject>::type | |
subject_type; | |
typedef typename mpl::eval_if< | |
traits::not_is_unused<Transformed> | |
, mpl::identity<Transformed> | |
, traits::attribute_of<subject_type> >::type | |
transformed_attribute_type; | |
attr_cast_parser(Subject const& subject) | |
: subject(subject) | |
{ | |
// If you got an error_invalid_expression error message here, | |
// then the expression (Subject) is not a valid spirit qi | |
// expression. | |
BOOST_SPIRIT_ASSERT_MATCH(qi::domain, Subject); | |
} | |
// If Exposed is given, we use the given type, otherwise all we can do | |
// is to guess, so we expose our inner type as an attribute and | |
// deal with the passed attribute inside the parse function. | |
template <typename Context, typename Iterator> | |
struct attribute | |
: mpl::if_<traits::not_is_unused<Exposed>, Exposed | |
, transformed_attribute_type> | |
{}; | |
template <typename Iterator, typename Context, typename Skipper | |
, typename Attribute> | |
bool parse(Iterator& first, Iterator const& last | |
, Context& context, Skipper const& skipper | |
, Attribute& attr) const | |
{ | |
// Find the real exposed attribute. If exposed is given, we use it | |
// otherwise we assume the exposed attribute type to be the actual | |
// attribute type as passed by the user. | |
typedef typename mpl::if_< | |
traits::not_is_unused<Exposed>, Exposed, Attribute>::type | |
exposed_attribute_type; | |
// do down-stream transformation, provides attribute for embedded | |
// parser | |
typedef traits::transform_attribute< | |
exposed_attribute_type, transformed_attribute_type, domain> | |
transform; | |
typename transform::type attr_ = transform::pre(attr); | |
if (!compile<qi::domain>(subject). | |
parse(first, last, context, skipper, attr_)) | |
{ | |
transform::fail(attr); | |
return false; | |
} | |
// do up-stream transformation, this mainly integrates the results | |
// back into the original attribute value, if appropriate | |
traits::post_transform(attr, attr_); | |
return true; | |
} | |
template <typename Context> | |
info what(Context& context) const | |
{ | |
return info("attr_cast" | |
, compile<qi::domain>(subject).what(context)); | |
} | |
Subject subject; | |
private: | |
// silence MSVC warning C4512: assignment operator could not be generated | |
attr_cast_parser& operator= (attr_cast_parser const&); | |
}; | |
/////////////////////////////////////////////////////////////////////////// | |
// Parser generator: make_xxx function (objects) | |
/////////////////////////////////////////////////////////////////////////// | |
template <typename Expr, typename Exposed, typename Transformed | |
, typename Modifiers> | |
struct make_primitive< | |
tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed>, Modifiers> | |
{ | |
typedef attr_cast_parser<Exposed, Transformed, Expr> result_type; | |
template <typename Terminal> | |
result_type operator()(Terminal const& term, unused_type) const | |
{ | |
typedef tag::stateful_tag< | |
Expr, tag::attr_cast, Exposed, Transformed> tag_type; | |
using spirit::detail::get_stateful_data; | |
return result_type(get_stateful_data<tag_type>::call(term)); | |
} | |
}; | |
}}} | |
#endif |