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Editing: lambda_functors.hpp
// Boost Lambda Library - lambda_functors.hpp ------------------------------- // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi) // // 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) // // For more information, see http://www.boost.org // ------------------------------------------------ #ifndef BOOST_LAMBDA_LAMBDA_FUNCTORS_HPP #define BOOST_LAMBDA_LAMBDA_FUNCTORS_HPP #include <boost/config.hpp> #include <boost/detail/workaround.hpp> #include <boost/utility/result_of.hpp> #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) #include <boost/mpl/or.hpp> #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_array.hpp> #define BOOST_LAMBDA_DISABLE_IF_ARRAY1(A1, R1)\ typename lazy_disable_if<is_array<A1>, typename R1 >::type #define BOOST_LAMBDA_DISABLE_IF_ARRAY2(A1, A2, R1, R2) \ typename lazy_disable_if<mpl::or_<is_array<A1>, is_array<A2> >, typename R1, R2 >::type #define BOOST_LAMBDA_DISABLE_IF_ARRAY3(A1, A2, A3, R1, R2, R3) \ typename lazy_disable_if<mpl::or_<is_array<A1>, is_array<A2>, is_array<A3> >, typename R1, R2, R3 >::type #else #define BOOST_LAMBDA_DISABLE_IF_ARRAY1(A1, R1) typename R1::type #define BOOST_LAMBDA_DISABLE_IF_ARRAY2(A1, A2, R1, R2) typename R1, R2::type #define BOOST_LAMBDA_DISABLE_IF_ARRAY3(A1, A2, A3, R1, R2, R3) typename R1, R2, R3::type #endif namespace boost { namespace lambda { // -- lambda_functor -------------------------------------------- // -------------------------------------------------------------- //inline const null_type const_null_type() { return null_type(); } namespace detail { namespace { static const null_type constant_null_type = null_type(); } // unnamed } // detail class unused {}; #define cnull_type() detail::constant_null_type // -- free variables types -------------------------------------------------- // helper to work around the case where the nullary return type deduction // is always performed, even though the functor is not nullary namespace detail { template<int N, class Tuple> struct get_element_or_null_type { typedef typename detail::tuple_element_as_reference<N, Tuple>::type type; }; template<int N> struct get_element_or_null_type<N, null_type> { typedef null_type type; }; } template <int I> struct placeholder; template<> struct placeholder<FIRST> { template<class SigArgs> struct sig { typedef typename detail::get_element_or_null_type<0, SigArgs>::type type; }; template<class RET, CALL_TEMPLATE_ARGS> RET call(CALL_FORMAL_ARGS) const { BOOST_STATIC_ASSERT(boost::is_reference<RET>::value); CALL_USE_ARGS; // does nothing, prevents warnings for unused args return a; } }; template<> struct placeholder<SECOND> { template<class SigArgs> struct sig { typedef typename detail::get_element_or_null_type<1, SigArgs>::type type; }; template<class RET, CALL_TEMPLATE_ARGS> RET call(CALL_FORMAL_ARGS) const { CALL_USE_ARGS; return b; } }; template<> struct placeholder<THIRD> { template<class SigArgs> struct sig { typedef typename detail::get_element_or_null_type<2, SigArgs>::type type; }; template<class RET, CALL_TEMPLATE_ARGS> RET call(CALL_FORMAL_ARGS) const { CALL_USE_ARGS; return c; } }; template<> struct placeholder<EXCEPTION> { template<class SigArgs> struct sig { typedef typename detail::get_element_or_null_type<3, SigArgs>::type type; }; template<class RET, CALL_TEMPLATE_ARGS> RET call(CALL_FORMAL_ARGS) const { CALL_USE_ARGS; return env; } }; typedef const lambda_functor<placeholder<FIRST> > placeholder1_type; typedef const lambda_functor<placeholder<SECOND> > placeholder2_type; typedef const lambda_functor<placeholder<THIRD> > placeholder3_type; /////////////////////////////////////////////////////////////////////////////// // free variables are lambda_functors. This is to allow uniform handling with // other lambda_functors. // ------------------------------------------------------------------- #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400) #pragma warning(push) #pragma warning(disable:4512) //assignment operator could not be generated #endif // -- lambda_functor NONE ------------------------------------------------ template <class T> class lambda_functor : public T { BOOST_STATIC_CONSTANT(int, arity_bits = get_arity<T>::value); public: typedef T inherited; lambda_functor() {} lambda_functor(const lambda_functor& l) : inherited(l) {} lambda_functor(const T& t) : inherited(t) {} template <class SigArgs> struct sig { typedef typename inherited::template sig<typename SigArgs::tail_type>::type type; }; // Note that this return type deduction template is instantiated, even // if the nullary // operator() is not called at all. One must make sure that it does not fail. typedef typename inherited::template sig<null_type>::type nullary_return_type; // Support for boost::result_of. template <class Sig> struct result; template <class F> struct result<F()> { typedef nullary_return_type type; }; template <class F, class A> struct result<F(A)> { typedef typename sig<tuple<F, A> >::type type; }; template <class F, class A, class B> struct result<F(A, B)> { typedef typename sig<tuple<F, A, B> >::type type; }; template <class F, class A, class B, class C> struct result<F(A, B, C)> { typedef typename sig<tuple<F, A, B, C> >::type type; }; nullary_return_type operator()() const { return inherited::template call<nullary_return_type> (cnull_type(), cnull_type(), cnull_type(), cnull_type()); } template<class A> typename inherited::template sig<tuple<A&> >::type operator()(A& a) const { return inherited::template call< typename inherited::template sig<tuple<A&> >::type >(a, cnull_type(), cnull_type(), cnull_type()); } template<class A> BOOST_LAMBDA_DISABLE_IF_ARRAY1(A, inherited::template sig<tuple<A const&> >) operator()(A const& a) const { return inherited::template call< typename inherited::template sig<tuple<A const&> >::type >(a, cnull_type(), cnull_type(), cnull_type()); } template<class A, class B> typename inherited::template sig<tuple<A&, B&> >::type operator()(A& a, B& b) const { return inherited::template call< typename inherited::template sig<tuple<A&, B&> >::type >(a, b, cnull_type(), cnull_type()); } template<class A, class B> BOOST_LAMBDA_DISABLE_IF_ARRAY2(A, B, inherited::template sig<tuple<A const&, B&> >) operator()(A const& a, B& b) const { return inherited::template call< typename inherited::template sig<tuple<A const&, B&> >::type >(a, b, cnull_type(), cnull_type()); } template<class A, class B> BOOST_LAMBDA_DISABLE_IF_ARRAY2(A, B, inherited::template sig<tuple<A&, B const&> >) operator()(A& a, B const& b) const { return inherited::template call< typename inherited::template sig<tuple<A&, B const&> >::type >(a, b, cnull_type(), cnull_type()); } template<class A, class B> BOOST_LAMBDA_DISABLE_IF_ARRAY2(A, B, inherited::template sig<tuple<A const&, B const&> >) operator()(A const& a, B const& b) const { return inherited::template call< typename inherited::template sig<tuple<A const&, B const&> >::type >(a, b, cnull_type(), cnull_type()); } template<class A, class B, class C> typename inherited::template sig<tuple<A&, B&, C&> >::type operator()(A& a, B& b, C& c) const { return inherited::template call< typename inherited::template sig<tuple<A&, B&, C&> >::type >(a, b, c, cnull_type()); } template<class A, class B, class C> BOOST_LAMBDA_DISABLE_IF_ARRAY3(A, B, C, inherited::template sig<tuple<A const&, B const&, C const&> >) operator()(A const& a, B const& b, C const& c) const { return inherited::template call< typename inherited::template sig<tuple<A const&, B const&, C const&> >::type >(a, b, c, cnull_type()); } // for internal calls with env template<CALL_TEMPLATE_ARGS> typename inherited::template sig<tuple<CALL_REFERENCE_TYPES> >::type internal_call(CALL_FORMAL_ARGS) const { return inherited::template call<typename inherited::template sig<tuple<CALL_REFERENCE_TYPES> >::type>(CALL_ACTUAL_ARGS); } template<class A> const lambda_functor<lambda_functor_base< other_action<assignment_action>, boost::tuple<lambda_functor, typename const_copy_argument <const A>::type> > > operator=(const A& a) const { return lambda_functor_base< other_action<assignment_action>, boost::tuple<lambda_functor, typename const_copy_argument <const A>::type> > ( boost::tuple<lambda_functor, typename const_copy_argument <const A>::type>(*this, a) ); } template<class A> const lambda_functor<lambda_functor_base< other_action<subscript_action>, boost::tuple<lambda_functor, typename const_copy_argument <const A>::type> > > operator[](const A& a) const { return lambda_functor_base< other_action<subscript_action>, boost::tuple<lambda_functor, typename const_copy_argument <const A>::type> > ( boost::tuple<lambda_functor, typename const_copy_argument <const A>::type>(*this, a ) ); } }; #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400) #pragma warning(pop) #endif } // namespace lambda } // namespace boost namespace boost { #if !defined(BOOST_RESULT_OF_USE_DECLTYPE) || defined(BOOST_NO_CXX11_DECLTYPE) template<class T> struct result_of<boost::lambda::lambda_functor<T>()> { typedef typename boost::lambda::lambda_functor<T>::nullary_return_type type; }; template<class T> struct result_of<const boost::lambda::lambda_functor<T>()> { typedef typename boost::lambda::lambda_functor<T>::nullary_return_type type; }; #endif template<class T> struct tr1_result_of<boost::lambda::lambda_functor<T>()> { typedef typename boost::lambda::lambda_functor<T>::nullary_return_type type; }; template<class T> struct tr1_result_of<const boost::lambda::lambda_functor<T>()> { typedef typename boost::lambda::lambda_functor<T>::nullary_return_type type; }; } // is_placeholder #include <boost/is_placeholder.hpp> namespace boost { template<> struct is_placeholder< lambda::lambda_functor< lambda::placeholder<lambda::FIRST> > > { enum _vt { value = 1 }; }; template<> struct is_placeholder< lambda::lambda_functor< lambda::placeholder<lambda::SECOND> > > { enum _vt { value = 2 }; }; template<> struct is_placeholder< lambda::lambda_functor< lambda::placeholder<lambda::THIRD> > > { enum _vt { value = 3 }; }; } // namespace boost #endif
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