311 lines
11 KiB
C++
311 lines
11 KiB
C++
|
|
// Copyright (C) 2009-2012 Lorenzo Caminiti
|
|
// Distributed under the Boost Software License, Version 1.0
|
|
// (see accompanying file LICENSE_1_0.txt or a copy at
|
|
// http://www.boost.org/LICENSE_1_0.txt)
|
|
// Home at http://www.boost.org/libs/functional/overloaded_function
|
|
|
|
#ifndef DOXYGEN // Doxygen documentation only.
|
|
|
|
#if !BOOST_PP_IS_ITERATING
|
|
# ifndef BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_HPP_
|
|
# define BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_HPP_
|
|
|
|
# include <boost/functional/overloaded_function/detail/base.hpp>
|
|
# include <boost/functional/overloaded_function/detail/function_type.hpp>
|
|
# include <boost/functional/overloaded_function/config.hpp>
|
|
# include <boost/typeof/typeof.hpp>
|
|
# include <boost/preprocessor/iteration/iterate.hpp>
|
|
# include <boost/preprocessor/repetition/enum.hpp>
|
|
# include <boost/preprocessor/repetition/repeat.hpp>
|
|
# include <boost/preprocessor/control/expr_iif.hpp>
|
|
# include <boost/preprocessor/control/expr_if.hpp>
|
|
# include <boost/preprocessor/comparison/greater.hpp>
|
|
# include <boost/preprocessor/comparison/less.hpp>
|
|
# include <boost/preprocessor/cat.hpp>
|
|
# include <boost/preprocessor/arithmetic/add.hpp>
|
|
# include <boost/preprocessor/arithmetic/sub.hpp>
|
|
# include <boost/preprocessor/tuple/eat.hpp>
|
|
# include <boost/preprocessor/logical/and.hpp>
|
|
# include <boost/preprocessor/logical/not.hpp>
|
|
# include <boost/preprocessor/facilities/expand.hpp>
|
|
|
|
#define BOOST_FUNCTIONAL_f_type(z, n, unused) \
|
|
BOOST_PP_CAT(F, n)
|
|
|
|
#define BOOST_FUNCTIONAL_f_arg(z, n, unused) \
|
|
BOOST_PP_CAT(f, n)
|
|
|
|
#define BOOST_FUNCTIONAL_f_tparam(z, n, unused) \
|
|
typename BOOST_FUNCTIONAL_f_type(z, n, ~) \
|
|
|
|
#define BOOST_FUNCTIONAL_f_tparam_dflt(z, n, is_tspec) \
|
|
BOOST_FUNCTIONAL_f_tparam(z, n, ~) \
|
|
/* overload requires at least 2 functors so F0 and F1 not optional */ \
|
|
BOOST_PP_EXPR_IIF(BOOST_PP_AND(BOOST_PP_NOT(is_tspec), \
|
|
BOOST_PP_GREATER(n, 1)), \
|
|
= void \
|
|
)
|
|
|
|
#define BOOST_FUNCTIONAL_f_arg_decl(z, n, unused) \
|
|
BOOST_FUNCTIONAL_f_type(z, n, ~) /* no qualifier to deduce tparam */ \
|
|
BOOST_FUNCTIONAL_f_arg(z, n, ~)
|
|
|
|
#define BOOST_FUNCTIONAL_g_type(z, n, unused) \
|
|
BOOST_PP_CAT(G, n)
|
|
|
|
#define BOOST_FUNCTIONAL_g_arg(z, n, unused) \
|
|
BOOST_PP_CAT(g, n)
|
|
|
|
#define BOOST_FUNCTIONAL_g_tparam(z, n, unused) \
|
|
typename BOOST_FUNCTIONAL_g_type(z, n, ~)
|
|
|
|
#define BOOST_FUNCTIONAL_g_arg_decl(z, n, unused) \
|
|
BOOST_FUNCTIONAL_g_type(z, n, ~) /* no qualifier to deduce tparam */ \
|
|
BOOST_FUNCTIONAL_g_arg(z, n, ~)
|
|
|
|
#define BOOST_FUNCTIONAL_base(z, n, unused) \
|
|
::boost::overloaded_function_detail::base< \
|
|
BOOST_FUNCTIONAL_f_type(z, n, ~) \
|
|
>
|
|
|
|
#define BOOST_FUNCTIONAL_inherit(z, n, unused) \
|
|
public BOOST_FUNCTIONAL_base(z, n, ~)
|
|
|
|
#define BOOST_FUNCTIONAL_base_init(z, n, unused) \
|
|
BOOST_FUNCTIONAL_base(z, n, ~)(BOOST_FUNCTIONAL_g_arg(z, n, ~))
|
|
|
|
#define BOOST_FUNCTIONAL_using_operator_call(z, n, unused) \
|
|
using BOOST_FUNCTIONAL_base(z, n, ~)::operator();
|
|
|
|
#define BOOST_FUNCTIONAL_function_type(z, n, unused) \
|
|
typename ::boost::overloaded_function_detail::function_type< \
|
|
BOOST_FUNCTIONAL_f_type(z, n, ~) \
|
|
>::type
|
|
|
|
# define BOOST_PP_ITERATION_PARAMS_1 \
|
|
/* at least 2 func to overload so start from 2 to MAX */ \
|
|
/* (cannot iterate [0, MAX-2) because error on Sun) */ \
|
|
(3, (2, BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX, \
|
|
"boost/functional/overloaded_function.hpp"))
|
|
# include BOOST_PP_ITERATE() // Iterate over function arity.
|
|
|
|
#undef BOOST_FUNCTIONAL_f_type
|
|
#undef BOOST_FUNCTIONAL_f_arg
|
|
#undef BOOST_FUNCTIONAL_f_tparam
|
|
#undef BOOST_FUNCTIONAL_f_arg_decl
|
|
#undef BOOST_FUNCTIONAL_f_tparam_dflt
|
|
#undef BOOST_FUNCTIONAL_g_type
|
|
#undef BOOST_FUNCTIONAL_g_arg
|
|
#undef BOOST_FUNCTIONAL_g_tparam
|
|
#undef BOOST_FUNCTIONAL_g_arg_decl
|
|
#undef BOOST_FUNCTIONAL_base
|
|
#undef BOOST_FUNCTIONAL_inherit
|
|
#undef BOOST_FUNCTIONAL_base_init
|
|
#undef BOOST_FUNCTIONAL_using_operator_call
|
|
#undef BOOST_FUNCTIONAL_function_type
|
|
|
|
# endif // #include guard
|
|
|
|
#elif BOOST_PP_ITERATION_DEPTH() == 1
|
|
# define BOOST_FUNCTIONAL_overloads \
|
|
/* iterate as OVERLOADS, OVERLOADS-1, OVERLOADS-2, ... */ \
|
|
/* (add 2 because iteration started from 2 to MAX) */ \
|
|
BOOST_PP_ADD(2, BOOST_PP_SUB( \
|
|
BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX, \
|
|
BOOST_PP_FRAME_ITERATION(1)))
|
|
# define BOOST_FUNCTIONAL_is_tspec \
|
|
/* if template specialization */ \
|
|
BOOST_PP_LESS(BOOST_FUNCTIONAL_overloads, \
|
|
BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX)
|
|
|
|
// For type-of emulation: This must be included at this pp iteration level.
|
|
# include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
|
|
|
|
namespace boost {
|
|
|
|
template<
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_f_tparam_dflt,
|
|
BOOST_FUNCTIONAL_is_tspec)
|
|
>
|
|
class overloaded_function
|
|
// Template specialization.
|
|
BOOST_PP_EXPR_IIF(BOOST_PP_EXPAND(BOOST_FUNCTIONAL_is_tspec), <)
|
|
BOOST_PP_IIF(BOOST_FUNCTIONAL_is_tspec,
|
|
BOOST_PP_ENUM
|
|
,
|
|
BOOST_PP_TUPLE_EAT(3)
|
|
)(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_f_type, ~)
|
|
BOOST_PP_EXPR_IIF(BOOST_PP_EXPAND(BOOST_FUNCTIONAL_is_tspec), >)
|
|
// Bases (overloads >= 2 so always at least 2 bases).
|
|
: BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads,
|
|
BOOST_FUNCTIONAL_inherit, ~)
|
|
{
|
|
public:
|
|
template<
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_g_tparam, ~)
|
|
> /* implicit */ inline overloaded_function(
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads,
|
|
BOOST_FUNCTIONAL_g_arg_decl, ~))
|
|
// Overloads >= 2 so always at least 2 bases to initialize.
|
|
: BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads,
|
|
BOOST_FUNCTIONAL_base_init, ~)
|
|
{}
|
|
|
|
BOOST_PP_REPEAT(BOOST_FUNCTIONAL_overloads,
|
|
BOOST_FUNCTIONAL_using_operator_call, ~)
|
|
};
|
|
|
|
template<
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_f_tparam, ~)
|
|
>
|
|
overloaded_function<
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_function_type, ~)
|
|
> make_overloaded_function(
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_f_arg_decl, ~)
|
|
) {
|
|
return overloaded_function<
|
|
BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads,
|
|
BOOST_FUNCTIONAL_function_type, ~)
|
|
>(BOOST_PP_ENUM(BOOST_FUNCTIONAL_overloads, BOOST_FUNCTIONAL_f_arg, ~));
|
|
}
|
|
|
|
} // namespace
|
|
|
|
// For type-of emulation: Register overloaded function type (for _AUTO, etc).
|
|
BOOST_TYPEOF_REGISTER_TEMPLATE(boost::overloaded_function,
|
|
BOOST_FUNCTIONAL_overloads)
|
|
|
|
# undef BOOST_FUNCTIONAL_overloads
|
|
# undef BOOST_FUNCTIONAL_is_tspec
|
|
#endif // iteration
|
|
|
|
// DOCUMENTATION //
|
|
|
|
#else // DOXYGEN
|
|
|
|
/** @file
|
|
@brief Overload distinct function pointers, function references, and
|
|
monomorphic function objects into a single function object.
|
|
*/
|
|
|
|
namespace boost {
|
|
|
|
/**
|
|
@brief Function object to overload functions with distinct signatures.
|
|
|
|
This function object aggregates together calls to functions of all the
|
|
specified function types <c>F1</c>, <c>F2</c>, etc which must have distinct
|
|
function signatures from one another.
|
|
|
|
@Params
|
|
@Param{F<em>i</em>,
|
|
Each function type must be specified using the following syntax (which is
|
|
Boost.Function's preferred syntax):
|
|
@code
|
|
result_type (argument1_type\, argumgnet2_type\, ...)
|
|
@endcode
|
|
}
|
|
@EndParams
|
|
|
|
In some cases, the @RefFunc{make_overloaded_function} function template can be
|
|
useful to construct an overloaded function object without explicitly
|
|
specifying the function types.
|
|
|
|
At least two distinct function types must be specified (because there is
|
|
nothing to overload between one or zero functions).
|
|
The maximum number of functions to overload is given by the
|
|
@RefMacro{BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX}
|
|
configuration macro.
|
|
The maximum number of function parameters for each of the specified function
|
|
types is given by the
|
|
@RefMacro{BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_ARITY_MAX}
|
|
configuration macro.
|
|
|
|
@See @RefSect{tutorial, Tutorial} section, @RefFunc{make_overloaded_function},
|
|
@RefMacro{BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX},
|
|
@RefMacro{BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_ARITY_MAX},
|
|
Boost.Function.
|
|
*/
|
|
template<typename F1, typename F2, ...>
|
|
class overloaded_function {
|
|
public:
|
|
/**
|
|
@brief Construct the overloaded function object.
|
|
|
|
Any function pointer, function reference, and monomorphic function object
|
|
that can be converted to a <c>boost::function</c> function object can be
|
|
specified as parameter.
|
|
|
|
@Note Unfortunately, it is not possible to support polymorphic function
|
|
objects (as explained <a
|
|
href="http://lists.boost.org/Archives/boost/2012/03/191744.php">here</a>).
|
|
*/
|
|
overloaded_function(const boost::function<F1>&,
|
|
const boost::function<F2>&, ...);
|
|
|
|
/**
|
|
@brief Call operator matching the signature of the function type specified
|
|
as 1st template parameter.
|
|
|
|
This will in turn invoke the call operator of the 1st function passed to
|
|
the constructor.
|
|
*/
|
|
typename boost::function_traits<F1>::result_type operator()(
|
|
typename boost::function_traits<F1>::arg1_type,
|
|
typename boost::function_traits<F1>::arg2_type,
|
|
...) const;
|
|
|
|
/**
|
|
@brief Call operator matching the signature of the function type specified
|
|
as 2nd template parameter.
|
|
|
|
This will in turn invoke the call operator of the 2nd function passed to
|
|
the constructor.
|
|
|
|
@Note Similar call operators are present for all specified function types
|
|
<c>F1</c>, <c>F2</c>, etc (even if not exhaustively listed by this
|
|
documentation).
|
|
*/
|
|
typename boost::function_traits<F2>::result_type operator()(
|
|
typename boost::function_traits<F2>::arg1_type,
|
|
typename boost::function_traits<F2>::arg2_type,
|
|
...) const;
|
|
};
|
|
|
|
/**
|
|
@brief Make an overloaded function object without explicitly specifying the
|
|
function types.
|
|
|
|
This function template creates and returns an @RefClass{overloaded_function}
|
|
object that overloads all the specified functions <c>f1</c>, <c>f2</c>, etc.
|
|
|
|
The function types are internally determined from the template parameter types
|
|
so they do not need to be explicitly specified.
|
|
Therefore, this function template usually has a more concise syntax when
|
|
compared with @RefClass{overloaded_function}.
|
|
This is especially useful when the explicit type of the returned
|
|
@RefClass{overloaded_function} object does not need to be known (e.g., when
|
|
used with Boost.Typeof's <c>BOOST_AUTO</c>, C++11 <c>auto</c>, or when the
|
|
overloaded function object is handled using a function template parameter, see
|
|
the @RefSect{tutorial, Tutorial} section).
|
|
|
|
The maximum number of functions to overload is given by the
|
|
@RefMacro{BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX}
|
|
configuration macro.
|
|
|
|
@Note In this documentation, <c>__function_type__</c> is a placeholder for a
|
|
symbol that is specific to the implementation of this library.
|
|
|
|
@See @RefSect{tutorial, Tutorial} section, @RefClass{overloaded_function},
|
|
@RefMacro{BOOST_FUNCTIONAL_OVERLOADED_FUNCTION_CONFIG_OVERLOAD_MAX}.
|
|
*/
|
|
template<typename F1, typename F2, ...>
|
|
overloaded_function<
|
|
__function_type__<F1>, __function_type__<F2>, ...
|
|
> make_overloaded_function(F1 f1, F2 f2, ...);
|
|
|
|
} // namespace
|
|
|
|
#endif // DOXYGEN
|
|
|