Chris@16: // Boost Lambda Library -- switch.hpp -----------------------------------
Chris@16: //
Chris@16: // Copyright (C) 2000 Gary Powell (powellg@amazon.com)
Chris@16: // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // For more information, see www.boost.org
Chris@16: 
Chris@16: // --------------------------------------------------------------------------
Chris@16: 
Chris@16: #if !defined(BOOST_LAMBDA_SWITCH_HPP)
Chris@16: #define BOOST_LAMBDA_SWITCH_HPP
Chris@16: 
Chris@16: #include "boost/lambda/core.hpp"
Chris@16: #include "boost/lambda/detail/control_constructs_common.hpp"
Chris@16: 
Chris@16: #include "boost/preprocessor/enum_shifted_params.hpp"
Chris@16: #include "boost/preprocessor/repeat_2nd.hpp"
Chris@16: #include "boost/preprocessor/tuple.hpp"
Chris@16: 
Chris@16: namespace boost { 
Chris@16: namespace lambda {
Chris@16: 
Chris@16: // Switch actions
Chris@16: template <int N, class Switch1 = null_type, class Switch2 = null_type, 
Chris@16:           class Switch3 = null_type, class Switch4 = null_type,
Chris@16:           class Switch5 = null_type, class Switch6 = null_type, 
Chris@16:           class Switch7 = null_type, class Switch8 = null_type, 
Chris@16:           class Switch9 = null_type>
Chris@16: struct switch_action {};
Chris@16: 
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16:   // templates to represent special lambda functors for the cases in 
Chris@16:   // switch statements
Chris@16:   
Chris@16: template <int Value> struct case_label {};
Chris@16: struct default_label {};
Chris@16: 
Chris@16: template<class Type> struct switch_case_tag {};
Chris@16: 
Chris@16:   // a normal case is represented as:
Chris@16:   // tagged_lambda_functor<switch_case_tag<case_label<N> > >, LambdaFunctor>
Chris@16:   
Chris@16:   // the default case as:
Chris@16:   // tagged_lambda_functor<switch_case_tag<default_label> >, LambdaFunctor>
Chris@16: 
Chris@16: 
Chris@16: } // end detail
Chris@16: 
Chris@16: 
Chris@16: /// create switch_case_tag tagged_lambda_functors
Chris@16: template <int CaseValue, class Arg>
Chris@16: inline const 
Chris@16: tagged_lambda_functor<
Chris@16:   detail::switch_case_tag<detail::case_label<CaseValue> >, 
Chris@16:   lambda_functor<Arg> 
Chris@16: > 
Chris@16: case_statement(const lambda_functor<Arg>& a) { 
Chris@16:   return 
Chris@16:     tagged_lambda_functor<
Chris@16:       detail::switch_case_tag<detail::case_label<CaseValue> >, 
Chris@16:       lambda_functor<Arg> 
Chris@16:     >(a); 
Chris@16: }
Chris@16: 
Chris@16: // No case body case.
Chris@16: template <int CaseValue>
Chris@16: inline const 
Chris@16: tagged_lambda_functor<
Chris@16:   detail::switch_case_tag<detail::case_label<CaseValue> >,
Chris@16:   lambda_functor< 
Chris@16:     lambda_functor_base< 
Chris@16:       do_nothing_action, 
Chris@16:       null_type
Chris@16:     > 
Chris@16:   > 
Chris@16: > 
Chris@16: case_statement() { 
Chris@16: return 
Chris@16:   tagged_lambda_functor<
Chris@16:     detail::switch_case_tag<detail::case_label<CaseValue> >,
Chris@16:     lambda_functor< 
Chris@16:       lambda_functor_base< 
Chris@16:         do_nothing_action, 
Chris@16:         null_type
Chris@16:       > 
Chris@16:     > 
Chris@16:   > () ;
Chris@16: }
Chris@16: 
Chris@16: // default label
Chris@16: template <class Arg>
Chris@16: inline const 
Chris@16: tagged_lambda_functor<
Chris@16:   detail::switch_case_tag<detail::default_label>, 
Chris@16:   lambda_functor<Arg> 
Chris@16: > 
Chris@16: default_statement(const lambda_functor<Arg>& a) { 
Chris@16:   return 
Chris@16:     tagged_lambda_functor<
Chris@16:       detail::switch_case_tag<detail::default_label>, 
Chris@16:       lambda_functor<Arg> 
Chris@16:     >(a); 
Chris@16: }
Chris@16: 
Chris@16: // default lable, no case body case.
Chris@16: inline const 
Chris@16: tagged_lambda_functor<
Chris@16:   detail::switch_case_tag<detail::default_label>,
Chris@16:   lambda_functor< 
Chris@16:     lambda_functor_base< 
Chris@16:       do_nothing_action, 
Chris@16:       null_type
Chris@16:     > 
Chris@16:   > 
Chris@16: > 
Chris@16: default_statement() { 
Chris@16: return 
Chris@16:       lambda_functor_base< 
Chris@16:         do_nothing_action, 
Chris@16:         null_type 
Chris@16:       > () ;
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: // Specializations for lambda_functor_base of case_statement -----------------
Chris@16: 
Chris@16: // 0 case type:
Chris@16: // useless (just the condition part) but provided for completeness.
Chris@16: template<class Args>
Chris@16: class 
Chris@16: lambda_functor_base<
Chris@16:   switch_action<1>, 
Chris@16:   Args
Chris@16: > 
Chris@16: {
Chris@16: public:
Chris@16:   Args args;
Chris@16:   template <class SigArgs> struct sig { typedef void type; };
Chris@16: public:
Chris@16:   explicit lambda_functor_base(const Args& a) : args(a) {}
Chris@16: 
Chris@16:   template<class RET, CALL_TEMPLATE_ARGS>
Chris@16:   RET call(CALL_FORMAL_ARGS) const {
Chris@16:     detail::select(::boost::tuples::get<1>(args), CALL_ACTUAL_ARGS);  
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: // 1 case type:
Chris@16: // template<class Args, int Case1>
Chris@16: // class 
Chris@16: // lambda_functor_base<
Chris@16: //   action<
Chris@16: //     2, 
Chris@16: //     return_void_action<switch_action<detail::case_label<Case1> > > 
Chris@16: //   >, 
Chris@16: //   Args
Chris@16: // > 
Chris@16: // {
Chris@16: //   Args args;
Chris@16: // public:
Chris@16: //   explicit lambda_functor_base(const Args& a) : args(a) {}
Chris@16: 
Chris@16: //   template<class RET, class A, class B, class C>
Chris@16: //   RET call(A& a, B& b, C& c) const {
Chris@16: //     switch( detail::select(::boost::tuples::get<0>(args), a, b, c) )  
Chris@16: //     {
Chris@16: //       case Case1:                
Chris@16: //         detail::select(::boost::tuples::get<1>(args), a, b, c);
Chris@16: //         break;
Chris@16: //     }
Chris@16: //   }
Chris@16: // };
Chris@16: 
Chris@16: // switch with default being the sole label - doesn't make much sense but
Chris@16: // it is there for completeness
Chris@16: // template<class Args>
Chris@16: // class
Chris@16: // lambda_functor_base<
Chris@16: //   action<
Chris@16: //     2,
Chris@16: //     return_void_action<switch_action<detail::default_label> >
Chris@16: //   >,
Chris@16: //   Args
Chris@16: // >
Chris@16: // {
Chris@16: //   Args args;
Chris@16: // public:
Chris@16: //   explicit lambda_functor_base(const Args& a) : args(a) {}
Chris@16: // 
Chris@16: //   template<class RET, class A, class B, class C>
Chris@16: //   RET call(A& a, B& b, C& c) const {
Chris@16: //     switch( detail::select(::boost::tuples::get<0>(args), a, b, c) )
Chris@16: //     {
Chris@16: //       default:
Chris@16: //         detail::select(::boost::tuples::get<1>(args), a, b, c);
Chris@16: //         break;
Chris@16: //     }
Chris@16: //   }
Chris@16: // };
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: // // 2 case type:
Chris@16: // The different specializations are generated with Vesa Karvonen's 
Chris@16: // preprocessor library.
Chris@16: 
Chris@16: // This is just a comment to show what the generated classes look like
Chris@16: 
Chris@16: // template<class Args, int Case1, int Case2>
Chris@16: // class 
Chris@16: // lambda_functor_base<
Chris@16: //   action<3, 
Chris@16: //     return_void_action< 
Chris@16: //       switch_action< 
Chris@16: //         detail::case_label<Case1>,
Chris@16: //         detail::case_label<Case2>
Chris@16: //       > 
Chris@16: //     > 
Chris@16: //   >, 
Chris@16: //   Args
Chris@16: // > 
Chris@16: // {
Chris@16: //   Args args;
Chris@16: // public:
Chris@16: //   explicit lambda_functor_base(const Args& a) : args(a) {}
Chris@16: 
Chris@16: //   template<class RET, class A, class B, class C>
Chris@16: //   RET call(A& a, B& b, C& c) const {
Chris@16: //     switch( detail::select(::boost::tuples::get<0>(args), a, b, c) )  
Chris@16: //     {
Chris@16: //       case Case1:                
Chris@16: //         detail::select(::boost::tuples::get<1>(args), a, b, c);
Chris@16: //         break;
Chris@16: //       case Case2:                
Chris@16: //         detail::select(::boost::tuples::get<2>(args), a, b, c);
Chris@16: //         break;
Chris@16: //     }
Chris@16: //   }
Chris@16: // };
Chris@16: 
Chris@16: // template<class Args, int Case1>
Chris@16: // class 
Chris@16: // lambda_functor_base<
Chris@16: //   action<3, 
Chris@16: //     return_void_action< 
Chris@16: //       switch_action< 
Chris@16: //         detail::case_label<Case1>,
Chris@16: //         detail::default_label 
Chris@16: //       > 
Chris@16: //     > 
Chris@16: //   >, 
Chris@16: //   Args
Chris@16: // > 
Chris@16: // {
Chris@16: //   Args args;
Chris@16: // public:
Chris@16: //   explicit lambda_functor_base(const Args& a) : args(a) {}
Chris@16: 
Chris@16: //   template<class RET, class A, class B, class C>
Chris@16: //   RET call(A& a, B& b, C& c) const {
Chris@16: //     switch( detail::select(::boost::tuples::get<0>(args), a, b, c) )  
Chris@16: //     {
Chris@16: //       case Case1:                
Chris@16: //         detail::select(::boost::tuples::get<1>(args), a, b, c);
Chris@16: //         break;
Chris@16: //       default:                
Chris@16: //         detail::select(::boost::tuples::get<2>(args), a, b, c);
Chris@16: //         break;
Chris@16: //     }
Chris@16: //   }
Chris@16: // };
Chris@16: // -------------------------
Chris@16: 
Chris@16: // Some helper preprocessor macros ---------------------------------
Chris@16: 
Chris@16: // BOOST_LAMBDA_A_I_LIST(N, X) is a list of form X0, X1, ..., XN
Chris@16: // BOOST_LAMBDA_A_I_B_LIST(N, X, Y) is a list of form X0 Y, X1 Y, ..., XN Y
Chris@16: 
Chris@16: #define BOOST_LAMBDA_A_I(z, i, A) \
Chris@16: BOOST_PP_COMMA_IF(i) BOOST_PP_CAT(A,i)
Chris@16: 
Chris@16: #define BOOST_LAMBDA_A_I_B(z, i, T) \
Chris@16: BOOST_PP_COMMA_IF(i) BOOST_PP_CAT(BOOST_PP_TUPLE_ELEM(2,0,T),i) BOOST_PP_TUPLE_ELEM(2,1,T)
Chris@16: 
Chris@16: #define BOOST_LAMBDA_A_I_LIST(i, A) \
Chris@16: BOOST_PP_REPEAT(i,BOOST_LAMBDA_A_I, A) 
Chris@16: 
Chris@16: #define BOOST_LAMBDA_A_I_B_LIST(i, A, B) \
Chris@16: BOOST_PP_REPEAT(i,BOOST_LAMBDA_A_I_B, (A,B)) 
Chris@16: 
Chris@16: 
Chris@16: // Switch related macros -------------------------------------------
Chris@16: #define BOOST_LAMBDA_SWITCH_CASE_BLOCK(z, N, A) \
Chris@16:   case Case##N: \
Chris@16:   detail::select(::boost::tuples::get<BOOST_PP_INC(N)>(args), CALL_ACTUAL_ARGS); \
Chris@16:   break;
Chris@16: 
Chris@16: #define BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST(N) \
Chris@16: BOOST_PP_REPEAT(N, BOOST_LAMBDA_SWITCH_CASE_BLOCK, FOO)
Chris@16: // 2 case type:
Chris@16: 
Chris@16: #define BOOST_LAMBDA_SWITCH_NO_DEFAULT_CASE(N)                                \
Chris@16: template<class Args, BOOST_LAMBDA_A_I_LIST(N, int Case)>                      \
Chris@16: class                                                                         \
Chris@16: lambda_functor_base<                                                          \
Chris@16:       switch_action<BOOST_PP_INC(N),                                          \
Chris@16:         BOOST_LAMBDA_A_I_B_LIST(N, detail::case_label<Case,>)                 \
Chris@16:       >,                                                                      \
Chris@16:   Args                                                                        \
Chris@16: >                                                                             \
Chris@16: {                                                                             \
Chris@16: public:                                                                       \
Chris@16:   Args args;                                                                  \
Chris@16:   template <class SigArgs> struct sig { typedef void type; };                 \
Chris@16: public:                                                                       \
Chris@16:   explicit lambda_functor_base(const Args& a) : args(a) {}                    \
Chris@16:                                                                               \
Chris@16:   template<class RET, CALL_TEMPLATE_ARGS>                                     \
Chris@16:   RET call(CALL_FORMAL_ARGS) const {                                          \
Chris@16:     switch( detail::select(::boost::tuples::get<0>(args), CALL_ACTUAL_ARGS) ) \
Chris@16:     {                                                                         \
Chris@16:       BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST(N)                                  \
Chris@16:     }                                                                         \
Chris@16:   }                                                                           \
Chris@16: };
Chris@16: 
Chris@16:         
Chris@16: 
Chris@16: #define BOOST_LAMBDA_SWITCH_WITH_DEFAULT_CASE(N)                              \
Chris@16: template<                                                                     \
Chris@16:   class Args BOOST_PP_COMMA_IF(BOOST_PP_DEC(N))                               \
Chris@16:   BOOST_LAMBDA_A_I_LIST(BOOST_PP_DEC(N), int Case)                            \
Chris@16: >                                                                             \
Chris@16: class                                                                         \
Chris@16: lambda_functor_base<                                                          \
Chris@16:       switch_action<BOOST_PP_INC(N),                                          \
Chris@16:         BOOST_LAMBDA_A_I_B_LIST(BOOST_PP_DEC(N),                              \
Chris@16:                                 detail::case_label<Case, >)                   \
Chris@16:         BOOST_PP_COMMA_IF(BOOST_PP_DEC(N))                                    \
Chris@16:         detail::default_label                                                 \
Chris@16:       >,                                                                      \
Chris@16:   Args                                                                        \
Chris@16: >                                                                             \
Chris@16: {                                                                             \
Chris@16: public:                                                                       \
Chris@16:   Args args;                                                                  \
Chris@16:   template <class SigArgs> struct sig { typedef void type; };                 \
Chris@16: public:                                                                       \
Chris@16:   explicit lambda_functor_base(const Args& a) : args(a) {}                    \
Chris@16:                                                                               \
Chris@16:   template<class RET, CALL_TEMPLATE_ARGS>                                     \
Chris@16:   RET call(CALL_FORMAL_ARGS) const {                                          \
Chris@16:     switch( detail::select(::boost::tuples::get<0>(args), CALL_ACTUAL_ARGS) ) \
Chris@16:     {                                                                         \
Chris@16:         BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST(BOOST_PP_DEC(N))                  \
Chris@16:       default:                                                                \
Chris@16:         detail::select(::boost::tuples::get<N>(args), CALL_ACTUAL_ARGS);      \
Chris@16:         break;                                                                \
Chris@16:     }                                                                         \
Chris@16:   }                                                                           \
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: // switch_statement bind functions -------------------------------------
Chris@16: 
Chris@16: // The zero argument case, for completeness sake
Chris@16: inline const 
Chris@16: lambda_functor< 
Chris@16:   lambda_functor_base< 
Chris@16:     do_nothing_action, 
Chris@16:     null_type
Chris@16:   > 
Chris@16: >
Chris@16: switch_statement() { 
Chris@16:   return 
Chris@16:       lambda_functor_base< 
Chris@16:         do_nothing_action, 
Chris@16:         null_type
Chris@16:       > 
Chris@16:   ();
Chris@16: }
Chris@16: 
Chris@16: // 1 argument case, this is useless as well, just the condition part
Chris@16: template <class TestArg>
Chris@16: inline const 
Chris@16: lambda_functor< 
Chris@16:   lambda_functor_base< 
Chris@16:     switch_action<1>, 
Chris@16:     tuple<lambda_functor<TestArg> >
Chris@16:   > 
Chris@16: >
Chris@16: switch_statement(const lambda_functor<TestArg>& a1) { 
Chris@16:   return 
Chris@16:       lambda_functor_base< 
Chris@16:          switch_action<1>, 
Chris@16:          tuple< lambda_functor<TestArg> > 
Chris@16:       > 
Chris@16:     ( tuple<lambda_functor<TestArg> >(a1));
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: #define HELPER(z, N, FOO)                                      \
Chris@16: BOOST_PP_COMMA_IF(N)                                           \
Chris@16: BOOST_PP_CAT(                                                  \
Chris@16:   const tagged_lambda_functor<detail::switch_case_tag<TagData, \
Chris@16:   N>)                                                          \
Chris@16: BOOST_PP_COMMA() Arg##N>& a##N
Chris@16: 
Chris@16: #define HELPER_LIST(N) BOOST_PP_REPEAT(N, HELPER, FOO)
Chris@16: 
Chris@16: 
Chris@16: #define BOOST_LAMBDA_SWITCH_STATEMENT(N)                              \
Chris@16: template <class TestArg,                                              \
Chris@16:           BOOST_LAMBDA_A_I_LIST(N, class TagData),                    \
Chris@16:           BOOST_LAMBDA_A_I_LIST(N, class Arg)>                        \
Chris@16: inline const                                                          \
Chris@16: lambda_functor<                                                       \
Chris@16:   lambda_functor_base<                                                \
Chris@16:         switch_action<BOOST_PP_INC(N),                                \
Chris@16:           BOOST_LAMBDA_A_I_LIST(N, TagData)                           \
Chris@16:         >,                                                            \
Chris@16:     tuple<lambda_functor<TestArg>, BOOST_LAMBDA_A_I_LIST(N, Arg)>     \
Chris@16:   >                                                                   \
Chris@16: >                                                                     \
Chris@16: switch_statement(                                                     \
Chris@16:   const lambda_functor<TestArg>& ta,                                  \
Chris@16:   HELPER_LIST(N)                                                      \
Chris@16: )                                                                     \
Chris@16: {                                                                     \
Chris@16:   return                                                              \
Chris@16:       lambda_functor_base<                                            \
Chris@16:             switch_action<BOOST_PP_INC(N),                            \
Chris@16:               BOOST_LAMBDA_A_I_LIST(N, TagData)                       \
Chris@16:             >,                                                        \
Chris@16:         tuple<lambda_functor<TestArg>, BOOST_LAMBDA_A_I_LIST(N, Arg)> \
Chris@16:       >                                                               \
Chris@16:     ( tuple<lambda_functor<TestArg>, BOOST_LAMBDA_A_I_LIST(N, Arg)>   \
Chris@16:         (ta, BOOST_LAMBDA_A_I_LIST(N, a) ));                          \
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: // Here's the actual generation
Chris@16: 
Chris@16: #define BOOST_LAMBDA_SWITCH(N)           \
Chris@16: BOOST_LAMBDA_SWITCH_NO_DEFAULT_CASE(N)   \
Chris@16: BOOST_LAMBDA_SWITCH_WITH_DEFAULT_CASE(N)        
Chris@16: 
Chris@16: // Use this to avoid case 0, these macros work only from case 1 upwards
Chris@16: #define BOOST_LAMBDA_SWITCH_HELPER(z, N, A) \
Chris@16: BOOST_LAMBDA_SWITCH( BOOST_PP_INC(N) )
Chris@16: 
Chris@16: // Use this to avoid cases 0 and 1, these macros work only from case 2 upwards
Chris@16: #define BOOST_LAMBDA_SWITCH_STATEMENT_HELPER(z, N, A) \
Chris@16: BOOST_LAMBDA_SWITCH_STATEMENT(BOOST_PP_INC(N))
Chris@16: 
Chris@16: #ifdef BOOST_MSVC
Chris@16: #pragma warning(push)
Chris@16: #pragma warning(disable:4065)
Chris@16: #endif
Chris@16: 
Chris@16:   // up to 9 cases supported (counting default:)
Chris@16: BOOST_PP_REPEAT_2ND(9,BOOST_LAMBDA_SWITCH_HELPER,FOO)
Chris@16: BOOST_PP_REPEAT_2ND(9,BOOST_LAMBDA_SWITCH_STATEMENT_HELPER,FOO)
Chris@16: 
Chris@16: #ifdef BOOST_MSVC
Chris@16: #pragma warning(pop)
Chris@16: #endif
Chris@16: 
Chris@16: } // namespace lambda 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: 
Chris@16: #undef HELPER
Chris@16: #undef HELPER_LIST
Chris@16: 
Chris@16: #undef BOOST_LAMBDA_SWITCH_HELPER
Chris@16: #undef BOOST_LAMBDA_SWITCH
Chris@16: #undef BOOST_LAMBDA_SWITCH_NO_DEFAULT_CASE
Chris@16: #undef BOOST_LAMBDA_SWITCH_WITH_DEFAULT_CASE
Chris@16: 
Chris@16: #undef BOOST_LAMBDA_SWITCH_CASE_BLOCK
Chris@16: #undef BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST
Chris@16: 
Chris@16: #undef BOOST_LAMBDA_SWITCH_STATEMENT
Chris@16: #undef BOOST_LAMBDA_SWITCH_STATEMENT_HELPER
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: