285 lines
9.7 KiB
Plaintext
285 lines
9.7 KiB
Plaintext
|
///////////////////////////////////////////////////////////////////////////////
|
||
|
|
/// \file make.hpp
|
||
|
|
/// Contains definition of the make<> transform.
|
||
|
|
//
|
||
|
|
// Copyright 2008 Eric Niebler. 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)
|
||
|
|
|
||
|
|
#ifndef BOOST_PROTO_TRANSFORM_MAKE_HPP_EAN_12_02_2007
|
||
|
|
#define BOOST_PROTO_TRANSFORM_MAKE_HPP_EAN_12_02_2007
|
||
|
|
|
||
|
|
#include <boost/detail/workaround.hpp>
|
||
|
|
#include <boost/preprocessor/repetition/enum.hpp>
|
||
|
|
#include <boost/preprocessor/repetition/enum_params.hpp>
|
||
|
|
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
|
||
|
|
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
|
||
|
|
#include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
|
||
|
|
#include <boost/preprocessor/repetition/repeat_from_to.hpp>
|
||
|
|
#include <boost/preprocessor/facilities/intercept.hpp>
|
||
|
|
#include <boost/preprocessor/cat.hpp>
|
||
|
|
#include <boost/preprocessor/iteration/iterate.hpp>
|
||
|
|
#include <boost/preprocessor/selection/max.hpp>
|
||
|
|
#include <boost/preprocessor/arithmetic/inc.hpp>
|
||
|
|
#include <boost/mpl/and.hpp>
|
||
|
|
#include <boost/mpl/aux_/has_type.hpp>
|
||
|
|
#include <boost/proto/detail/template_arity.hpp>
|
||
|
|
#include <boost/utility/result_of.hpp>
|
||
|
|
#include <boost/proto/proto_fwd.hpp>
|
||
|
|
#include <boost/proto/traits.hpp>
|
||
|
|
#include <boost/proto/args.hpp>
|
||
|
|
#include <boost/proto/transform/impl.hpp>
|
||
|
|
#include <boost/proto/transform/detail/pack.hpp>
|
||
|
|
#include <boost/proto/detail/as_lvalue.hpp>
|
||
|
|
#include <boost/proto/detail/ignore_unused.hpp>
|
||
|
|
|
||
|
|
#if defined(_MSC_VER)
|
||
|
|
# pragma warning(push)
|
||
|
|
# pragma warning(disable : 4714) // function 'xxx' marked as __forceinline not inlined
|
||
|
|
#endif
|
||
|
|
|
||
|
|
namespace boost { namespace proto
|
||
|
|
{
|
||
|
|
namespace detail
|
||
|
|
{
|
||
|
|
template<typename T>
|
||
|
|
struct is_applyable
|
||
|
|
: mpl::and_<is_callable<T>, is_transform<T> >
|
||
|
|
{};
|
||
|
|
|
||
|
|
template<typename T, bool HasType = mpl::aux::has_type<T>::value>
|
||
|
|
struct nested_type
|
||
|
|
{
|
||
|
|
typedef typename T::type type;
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
struct nested_type<T, false>
|
||
|
|
{
|
||
|
|
typedef T type;
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename T, bool Applied>
|
||
|
|
struct nested_type_if
|
||
|
|
{
|
||
|
|
typedef T type;
|
||
|
|
static bool const applied = false;
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
struct nested_type_if<T, true>
|
||
|
|
: nested_type<T>
|
||
|
|
{
|
||
|
|
static bool const applied = true;
|
||
|
|
};
|
||
|
|
|
||
|
|
template<
|
||
|
|
typename R
|
||
|
|
, typename Expr, typename State, typename Data
|
||
|
|
BOOST_PROTO_TEMPLATE_ARITY_PARAM(long Arity = detail::template_arity<R>::value)
|
||
|
|
>
|
||
|
|
struct make_
|
||
|
|
{
|
||
|
|
typedef R type;
|
||
|
|
static bool const applied = false;
|
||
|
|
};
|
||
|
|
|
||
|
|
template<
|
||
|
|
typename R
|
||
|
|
, typename Expr, typename State, typename Data
|
||
|
|
, bool IsApplyable = is_applyable<R>::value
|
||
|
|
>
|
||
|
|
struct make_if_
|
||
|
|
: make_<R, Expr, State, Data>
|
||
|
|
{};
|
||
|
|
|
||
|
|
template<typename R, typename Expr, typename State, typename Data>
|
||
|
|
struct make_if_<R, Expr, State, Data, true>
|
||
|
|
: uncvref<typename when<_, R>::template impl<Expr, State, Data>::result_type>
|
||
|
|
{
|
||
|
|
static bool const applied = true;
|
||
|
|
};
|
||
|
|
|
||
|
|
#if BOOST_WORKAROUND(__GNUC__, == 3) || (BOOST_WORKAROUND(__GNUC__, == 4) && __GNUC_MINOR__ == 0)
|
||
|
|
// work around GCC bug
|
||
|
|
template<typename Tag, typename Args, long N, typename Expr, typename State, typename Data>
|
||
|
|
struct make_if_<proto::expr<Tag, Args, N>, Expr, State, Data, false>
|
||
|
|
{
|
||
|
|
typedef proto::expr<Tag, Args, N> type;
|
||
|
|
static bool const applied = false;
|
||
|
|
};
|
||
|
|
|
||
|
|
// work around GCC bug
|
||
|
|
template<typename Tag, typename Args, long N, typename Expr, typename State, typename Data>
|
||
|
|
struct make_if_<proto::basic_expr<Tag, Args, N>, Expr, State, Data, false>
|
||
|
|
{
|
||
|
|
typedef proto::basic_expr<Tag, Args, N> type;
|
||
|
|
static bool const applied = false;
|
||
|
|
};
|
||
|
|
#endif
|
||
|
|
|
||
|
|
template<typename Type, bool IsAggregate = detail::is_aggregate_<Type>::value>
|
||
|
|
struct construct_
|
||
|
|
{
|
||
|
|
typedef Type result_type;
|
||
|
|
|
||
|
|
BOOST_FORCEINLINE
|
||
|
|
Type operator ()() const
|
||
|
|
{
|
||
|
|
return Type();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Other overloads generated by the preprocessor
|
||
|
|
#include <boost/proto/transform/detail/construct_funop.hpp>
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename Type>
|
||
|
|
struct construct_<Type, true>
|
||
|
|
{
|
||
|
|
typedef Type result_type;
|
||
|
|
|
||
|
|
BOOST_FORCEINLINE
|
||
|
|
Type operator ()() const
|
||
|
|
{
|
||
|
|
return Type();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Other overloads generated by the preprocessor
|
||
|
|
#include <boost/proto/transform/detail/construct_pod_funop.hpp>
|
||
|
|
};
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
/// \brief A PrimitiveTransform which prevents another PrimitiveTransform
|
||
|
|
/// from being applied in an \c ObjectTransform.
|
||
|
|
///
|
||
|
|
/// When building higher order transforms with <tt>make\<\></tt> or
|
||
|
|
/// <tt>lazy\<\></tt>, you sometimes would like to build types that
|
||
|
|
/// are parameterized with Proto transforms. In such lambda-style
|
||
|
|
/// transforms, Proto will unhelpfully find all nested transforms
|
||
|
|
/// and apply them, even if you don't want them to be applied. Consider
|
||
|
|
/// the following transform, which will replace the \c _ in
|
||
|
|
/// <tt>Bar<_>()</tt> with <tt>proto::terminal\<int\>::type</tt>:
|
||
|
|
///
|
||
|
|
/// \code
|
||
|
|
/// template<typename T>
|
||
|
|
/// struct Bar
|
||
|
|
/// {};
|
||
|
|
///
|
||
|
|
/// struct Foo
|
||
|
|
/// : proto::when<_, Bar<_>() >
|
||
|
|
/// {};
|
||
|
|
///
|
||
|
|
/// proto::terminal<int>::type i = {0};
|
||
|
|
///
|
||
|
|
/// int main()
|
||
|
|
/// {
|
||
|
|
/// Foo()(i);
|
||
|
|
/// std::cout << typeid(Foo()(i)).name() << std::endl;
|
||
|
|
/// }
|
||
|
|
/// \endcode
|
||
|
|
///
|
||
|
|
/// If you actually wanted to default-construct an object of type
|
||
|
|
/// <tt>Bar\<_\></tt>, you would have to protect the \c _ to prevent
|
||
|
|
/// it from being applied. You can use <tt>proto::protect\<\></tt>
|
||
|
|
/// as follows:
|
||
|
|
///
|
||
|
|
/// \code
|
||
|
|
/// // OK: replace anything with Bar<_>()
|
||
|
|
/// struct Foo
|
||
|
|
/// : proto::when<_, Bar<protect<_> >() >
|
||
|
|
/// {};
|
||
|
|
/// \endcode
|
||
|
|
template<typename PrimitiveTransform>
|
||
|
|
struct protect : transform<protect<PrimitiveTransform> >
|
||
|
|
{
|
||
|
|
template<typename, typename, typename>
|
||
|
|
struct impl
|
||
|
|
{
|
||
|
|
typedef PrimitiveTransform result_type;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
/// \brief A PrimitiveTransform which computes a type by evaluating any
|
||
|
|
/// nested transforms and then constructs an object of that type.
|
||
|
|
///
|
||
|
|
/// The <tt>make\<\></tt> transform checks to see if \c Object is a template.
|
||
|
|
/// If it is, the template type is disassembled to find nested transforms.
|
||
|
|
/// Proto considers the following types to represent transforms:
|
||
|
|
///
|
||
|
|
/// \li Function types
|
||
|
|
/// \li Function pointer types
|
||
|
|
/// \li Types for which <tt>proto::is_callable\< type \>::value</tt> is \c true
|
||
|
|
///
|
||
|
|
/// <tt>boost::result_of\<make\<T\<X0,X1,...\> \>(Expr, State, Data)\>::type</tt>
|
||
|
|
/// is evaluated as follows. For each \c X in <tt>X0,X1,...</tt>, do:
|
||
|
|
///
|
||
|
|
/// \li If \c X is a template like <tt>U\<Y0,Y1,...\></tt>, then let <tt>X'</tt>
|
||
|
|
/// be <tt>boost::result_of\<make\<U\<Y0,Y1,...\> \>(Expr, State, Data)\>::type</tt>
|
||
|
|
/// (which evaluates this procedure recursively). Note whether any
|
||
|
|
/// substitutions took place during this operation.
|
||
|
|
/// \li Otherwise, if \c X is a transform, then let <tt>X'</tt> be
|
||
|
|
/// <tt>boost::result_of\<when\<_, X\>(Expr, State, Data)\>::type</tt>.
|
||
|
|
/// Note that a substitution took place.
|
||
|
|
/// \li Otherwise, let <tt>X'</tt> be \c X, and note that no substitution
|
||
|
|
/// took place.
|
||
|
|
/// \li If any substitutions took place in any of the above steps and
|
||
|
|
/// <tt>T\<X0',X1',...\></tt> has a nested <tt>::type</tt> typedef,
|
||
|
|
/// the result type is <tt>T\<X0',X1',...\>::type</tt>.
|
||
|
|
/// \li Otherwise, the result type is <tt>T\<X0',X1',...\></tt>.
|
||
|
|
///
|
||
|
|
/// Note that <tt>when\<\></tt> is implemented in terms of <tt>call\<\></tt>
|
||
|
|
/// and <tt>make\<\></tt>, so the above procedure is evaluated recursively.
|
||
|
|
template<typename Object>
|
||
|
|
struct make : transform<make<Object> >
|
||
|
|
{
|
||
|
|
template<typename Expr, typename State, typename Data>
|
||
|
|
struct impl : transform_impl<Expr, State, Data>
|
||
|
|
{
|
||
|
|
typedef typename detail::make_if_<Object, Expr, State, Data>::type result_type;
|
||
|
|
|
||
|
|
/// \return <tt>result_type()</tt>
|
||
|
|
BOOST_FORCEINLINE
|
||
|
|
result_type operator ()(
|
||
|
|
typename impl::expr_param
|
||
|
|
, typename impl::state_param
|
||
|
|
, typename impl::data_param
|
||
|
|
) const
|
||
|
|
{
|
||
|
|
return result_type();
|
||
|
|
}
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
/// INTERNAL ONLY
|
||
|
|
template<typename Fun>
|
||
|
|
struct make<detail::msvc_fun_workaround<Fun> >
|
||
|
|
: make<Fun>
|
||
|
|
{};
|
||
|
|
|
||
|
|
// Other specializations generated by the preprocessor.
|
||
|
|
#include <boost/proto/transform/detail/make.hpp>
|
||
|
|
#include <boost/proto/transform/detail/make_gcc_workaround.hpp>
|
||
|
|
|
||
|
|
/// INTERNAL ONLY
|
||
|
|
///
|
||
|
|
template<typename Object>
|
||
|
|
struct is_callable<make<Object> >
|
||
|
|
: mpl::true_
|
||
|
|
{};
|
||
|
|
|
||
|
|
/// INTERNAL ONLY
|
||
|
|
///
|
||
|
|
template<typename PrimitiveTransform>
|
||
|
|
struct is_callable<protect<PrimitiveTransform> >
|
||
|
|
: mpl::true_
|
||
|
|
{};
|
||
|
|
|
||
|
|
}}
|
||
|
|
|
||
|
|
#if defined(_MSC_VER)
|
||
|
|
# pragma warning(pop)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif
|