[ceph.git] / ceph / src / boost / boost / tti / has_enum.hpp


//  (C) Copyright Edward Diener 2019
//  Use, modification and distribution are subject to 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(BOOST_TTI_HAS_ENUM_HPP)
#define BOOST_TTI_HAS_ENUM_HPP

#include <boost/config.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/tti/gen/has_enum_gen.hpp>
#include <boost/tti/gen/namespace_gen.hpp>
#include <boost/tti/detail/denum.hpp>
#include <boost/tti/detail/ddeftype.hpp>

/*

  The succeeding comments in this file are in doxygen format.

*/

/** \file
*/

/// A macro which expands to a metafunction which tests whether an inner enum with a particular name exists.
/**

    BOOST_TTI_TRAIT_HAS_ENUM is a macro which expands to a metafunction.
    The metafunction tests whether an inner enum with a particular name exists
    and, optionally, whether an MPL lambda expression invoked with the inner enum
    is true or not. The macro takes the form of BOOST_TTI_TRAIT_HAS_ENUM(trait,name) where
    
    trait = the name of the metafunction <br/>
    name  = the name of the inner enum. The name can be that of an enum or, in C++11 on up, an enum class.

    BOOST_TTI_TRAIT_HAS_ENUM generates a metafunction called "trait" where 'trait' is the macro parameter.
    
  @code
  
              template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_U>
              struct trait
                {
                static const value = unspecified;
                typedef mpl::bool_<true-or-false> type;
                };

              The metafunction types and return:
    
                BOOST_TTI_TP_T = the enclosing type in which to look for our 'name'.
                                 The enclosing type can be a class, struct, or union.
                
                BOOST_TTI_TP_U = (optional) An optional template parameter, defaulting to a marker type.
                                   If specified it is an MPL lambda expression which is invoked 
                                   with the inner enum found and must return a constant boolean 
                                   value.
                                   
                returns = 'value' depends on whether or not the optional BOOST_TTI_TP_U is specified.
                
                          If BOOST_TTI_TP_U is not specified, then 'value' is true if the 'name' enum
                          exists within the enclosing type BOOST_TTI_TP_T; otherwise 'value' is false.
                          
                          If BOOST_TTI_TP_U is specified , then 'value' is true if the 'name' enum exists 
                          within the enclosing type BOOST_TTI_TP_T and the MPL lambda expression as specified 
                          by BOOST_TTI_TP_U, invoked by passing the actual inner enum of 'name', returns 
                          a 'value' of true; otherwise 'value' is false.
                             
                          The action taken with BOOST_TTI_TP_U occurs only when the 'name' enum exists 
                          within the enclosing type BOOST_TTI_TP_T.
                             
  @endcode
  
  Example usage:
  
  @code
  
  BOOST_TTI_TRAIT_HAS_ENUM(LookFor,MyType) generates the metafunction LookFor in the current scope
  to look for an inner enum called MyType.
  
  LookFor<EnclosingType>::value is true if MyType is an inner enum of EnclosingType, otherwise false.
  
  LookFor<EnclosingType,ALambdaExpression>::value is true if MyType is an inner enum of EnclosingType
    and invoking ALambdaExpression with the inner enum returns a value of true, otherwise false.
    
  A popular use of the optional MPL lambda expression is to check whether the enum found is the same  
  as another type, when the enum found is a typedef. In that case our example would be:
  
  LookFor<EnclosingType,boost::is_same<_,SomeOtherType> >::value is true if MyType is an inner enum
    of EnclosingType and is the same type as SomeOtherType.
  
  @endcode
  
*/
#define BOOST_TTI_TRAIT_HAS_ENUM(trait,name) \
  BOOST_TTI_DETAIL_TRAIT_HAS_ENUM(trait,name) \
  template \
    < \
    class BOOST_TTI_TP_T, \
    class BOOST_TTI_TP_U = BOOST_TTI_NAMESPACE::detail::deftype \
    > \
  struct trait \
    { \
    typedef typename \
    BOOST_PP_CAT(trait,_detail_enum)<BOOST_TTI_TP_T,BOOST_TTI_TP_U>::type type; \
    BOOST_STATIC_CONSTANT(bool,value=type::value); \
    }; \
/**/

/// A macro which expands to a metafunction which tests whether an inner enum with a particular name exists.
/**

    BOOST_TTI_HAS_ENUM is a macro which expands to a metafunction.
    The metafunction tests whether an inner enum with a particular name exists
    and, optionally, whether an MPL lambda expression invoked with the inner enum 
    is true or not. The macro takes the form of BOOST_TTI_HAS_ENUM(name) where
    
    name  = the name of the inner enum. The name can be that of an enum or, in C++11 on up, an enum class.

    BOOST_TTI_HAS_ENUM generates a metafunction called "has_enum_'name'" where 'name' is the macro parameter.
    
  @code
  
              template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_U>
              struct has_enum_'name'
                {
                static const value = unspecified;
                typedef mpl::bool_<true-or-false> type;
                };

              The metafunction types and return:
    
                BOOST_TTI_TP_T = the enclosing type in which to look for our 'name'.
                                 The enclosing type can be a class, struct, or union.
                
                BOOST_TTI_TP_U = (optional) An optional template parameter, defaulting to a marker type.
                                   If specified it is an MPL lambda expression which is invoked 
                                   with the inner enum found and must return a constant boolean 
                                   value.
                                   
                returns = 'value' depends on whether or not the optional BOOST_TTI_TP_U is specified.
                
                          If BOOST_TTI_TP_U is not specified, then 'value' is true if the 'name' enum 
                          exists within the enclosing type BOOST_TTI_TP_T; otherwise 'value' is false.
                          
                          If BOOST_TTI_TP_U is specified, then 'value' is true if the 'name' enum exists 
                          within the enclosing type BOOST_TTI_TP_T and the MPL lambda expression as specified 
                          by BOOST_TTI_TP_U, invoked by passing the actual inner enum of 'name', returns 
                          a 'value' of true; otherwise 'value' is false.
                             
                          The action taken with BOOST_TTI_TP_U occurs only when the 'name' enum exists 
                          within the enclosing type BOOST_TTI_TP_T.
                             
  @endcode
  
  Example usage:
  
  @code
  
  BOOST_TTI_HAS_ENUM(MyType) generates the metafunction has_enum_MyType in the current scope
  to look for an inner enum called MyType.
  
  has_enum_MyType<EnclosingType>::value is true if MyType is an inner enum of EnclosingType, otherwise false.
  
  has_class_MyType<EnclosingType,ALambdaExpression>::value is true if MyType is an inner enum of EnclosingType
    and invoking ALambdaExpression with the inner enum returns a value of true, otherwise false.
  
  A popular use of the optional MPL lambda expression is to check whether the enum found is the same  
  as another type, when the enum found is a typedef. In that case our example would be:
  
  has_enum_MyType<EnclosingType,boost::is_same<_,SomeOtherType> >::value is true if MyType is an inner enum
    of EnclosingType and is the same type as SomeOtherType.
  
  @endcode
  
*/
#define BOOST_TTI_HAS_ENUM(name) \
  BOOST_TTI_TRAIT_HAS_ENUM \
  ( \
  BOOST_TTI_HAS_ENUM_GEN(name), \
  name \
  ) \
/**/

#endif // BOOST_TTI_HAS_ENUM_HPP
Commit	Line	Data
f67539c2 TL	1
	2	// (C) Copyright Edward Diener 2019
	3	// Use, modification and distribution are subject to the Boost Software License,
	4	// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
	5	// http://www.boost.org/LICENSE_1_0.txt).
	6
	7	#if !defined(BOOST_TTI_HAS_ENUM_HPP)
	8	#define BOOST_TTI_HAS_ENUM_HPP
	9
	10	#include <boost/config.hpp>
	11	#include <boost/preprocessor/cat.hpp>
	12	#include <boost/tti/gen/has_enum_gen.hpp>
	13	#include <boost/tti/gen/namespace_gen.hpp>
	14	#include <boost/tti/detail/denum.hpp>
	15	#include <boost/tti/detail/ddeftype.hpp>
	16
	17	/*
	18
	19	The succeeding comments in this file are in doxygen format.
	20
	21	*/
	22
	23	/** \file
	24	*/
	25
	26	/// A macro which expands to a metafunction which tests whether an inner enum with a particular name exists.
	27	/**
	28
	29	BOOST_TTI_TRAIT_HAS_ENUM is a macro which expands to a metafunction.
	30	The metafunction tests whether an inner enum with a particular name exists
	31	and, optionally, whether an MPL lambda expression invoked with the inner enum
	32	is true or not. The macro takes the form of BOOST_TTI_TRAIT_HAS_ENUM(trait,name) where
	33
	34	trait = the name of the metafunction <br/>
	35	name = the name of the inner enum. The name can be that of an enum or, in C++11 on up, an enum class.
	36
	37	BOOST_TTI_TRAIT_HAS_ENUM generates a metafunction called "trait" where 'trait' is the macro parameter.
	38
	39	@code
	40
	41	template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_U>
	42	struct trait
	43	{
	44	static const value = unspecified;
	45	typedef mpl::bool_<true-or-false> type;
	46	};
	47
	48	The metafunction types and return:
	49
	50	BOOST_TTI_TP_T = the enclosing type in which to look for our 'name'.
	51	The enclosing type can be a class, struct, or union.
	52
	53	BOOST_TTI_TP_U = (optional) An optional template parameter, defaulting to a marker type.
	54	If specified it is an MPL lambda expression which is invoked
	55	with the inner enum found and must return a constant boolean
	56	value.
	57
	58	returns = 'value' depends on whether or not the optional BOOST_TTI_TP_U is specified.
	59
	60	If BOOST_TTI_TP_U is not specified, then 'value' is true if the 'name' enum
	61	exists within the enclosing type BOOST_TTI_TP_T; otherwise 'value' is false.
	62
	63	If BOOST_TTI_TP_U is specified , then 'value' is true if the 'name' enum exists
	64	within the enclosing type BOOST_TTI_TP_T and the MPL lambda expression as specified
65	by BOOST_TTI_TP_U, invoked by passing the actual inner enum of 'name', returns
66	a 'value' of true; otherwise 'value' is false.
67
68	The action taken with BOOST_TTI_TP_U occurs only when the 'name' enum exists
69	within the enclosing type BOOST_TTI_TP_T.
70
71	@endcode
72
73	Example usage:
74
75	@code
76
77	BOOST_TTI_TRAIT_HAS_ENUM(LookFor,MyType) generates the metafunction LookFor in the current scope
78	to look for an inner enum called MyType.
79
80	LookFor<EnclosingType>::value is true if MyType is an inner enum of EnclosingType, otherwise false.
81
82	LookFor<EnclosingType,ALambdaExpression>::value is true if MyType is an inner enum of EnclosingType
83	and invoking ALambdaExpression with the inner enum returns a value of true, otherwise false.
84
85	A popular use of the optional MPL lambda expression is to check whether the enum found is the same
86	as another type, when the enum found is a typedef. In that case our example would be:
87
88	LookFor<EnclosingType,boost::is_same<_,SomeOtherType> >::value is true if MyType is an inner enum
89	of EnclosingType and is the same type as SomeOtherType.
90
91	@endcode
92
93	*/
94	#define BOOST_TTI_TRAIT_HAS_ENUM(trait,name) \
95	BOOST_TTI_DETAIL_TRAIT_HAS_ENUM(trait,name) \
96	template \
97	< \
98	class BOOST_TTI_TP_T, \
99	class BOOST_TTI_TP_U = BOOST_TTI_NAMESPACE::detail::deftype \
100	> \
101	struct trait \
102	{ \
103	typedef typename \
104	BOOST_PP_CAT(trait,_detail_enum)<BOOST_TTI_TP_T,BOOST_TTI_TP_U>::type type; \
105	BOOST_STATIC_CONSTANT(bool,value=type::value); \
106	}; \
107	/**/
108
109	/// A macro which expands to a metafunction which tests whether an inner enum with a particular name exists.
110	/**
111
112	BOOST_TTI_HAS_ENUM is a macro which expands to a metafunction.
113	The metafunction tests whether an inner enum with a particular name exists
114	and, optionally, whether an MPL lambda expression invoked with the inner enum
115	is true or not. The macro takes the form of BOOST_TTI_HAS_ENUM(name) where
116
117	name = the name of the inner enum. The name can be that of an enum or, in C++11 on up, an enum class.
118
119	BOOST_TTI_HAS_ENUM generates a metafunction called "has_enum_'name'" where 'name' is the macro parameter.
120
121	@code
122
123	template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_U>
124	struct has_enum_'name'
125	{
126	static const value = unspecified;
127	typedef mpl::bool_<true-or-false> type;
128	};
129
130	The metafunction types and return:
131
132	BOOST_TTI_TP_T = the enclosing type in which to look for our 'name'.
133	The enclosing type can be a class, struct, or union.
134
135	BOOST_TTI_TP_U = (optional) An optional template parameter, defaulting to a marker type.
136	If specified it is an MPL lambda expression which is invoked
137	with the inner enum found and must return a constant boolean
138	value.
139
140	returns = 'value' depends on whether or not the optional BOOST_TTI_TP_U is specified.
141
142	If BOOST_TTI_TP_U is not specified, then 'value' is true if the 'name' enum
143	exists within the enclosing type BOOST_TTI_TP_T; otherwise 'value' is false.
144
145	If BOOST_TTI_TP_U is specified, then 'value' is true if the 'name' enum exists
146	within the enclosing type BOOST_TTI_TP_T and the MPL lambda expression as specified
147	by BOOST_TTI_TP_U, invoked by passing the actual inner enum of 'name', returns
148	a 'value' of true; otherwise 'value' is false.
149
150	The action taken with BOOST_TTI_TP_U occurs only when the 'name' enum exists
151	within the enclosing type BOOST_TTI_TP_T.
152
153	@endcode
154
155	Example usage:
156
157	@code
158
159	BOOST_TTI_HAS_ENUM(MyType) generates the metafunction has_enum_MyType in the current scope
160	to look for an inner enum called MyType.
161
162	has_enum_MyType<EnclosingType>::value is true if MyType is an inner enum of EnclosingType, otherwise false.
163
164	has_class_MyType<EnclosingType,ALambdaExpression>::value is true if MyType is an inner enum of EnclosingType
165	and invoking ALambdaExpression with the inner enum returns a value of true, otherwise false.
166
167	A popular use of the optional MPL lambda expression is to check whether the enum found is the same
168	as another type, when the enum found is a typedef. In that case our example would be:
169
170	has_enum_MyType<EnclosingType,boost::is_same<_,SomeOtherType> >::value is true if MyType is an inner enum
171	of EnclosingType and is the same type as SomeOtherType.
172
173	@endcode
174
175	*/
176	#define BOOST_TTI_HAS_ENUM(name) \
177	BOOST_TTI_TRAIT_HAS_ENUM \
178	( \
179	BOOST_TTI_HAS_ENUM_GEN(name), \
180	name \
181	) \
182	/**/
183
184	#endif // BOOST_TTI_HAS_ENUM_HPP