Subject: [Boost-commit] svn:boost r78434 - trunk/boost/detail
From: vicente.botet_at_[hidden]
Date: 2012-05-12 07:07:59
Author: viboes
Date: 2012-05-12 07:07:58 EDT (Sat, 12 May 2012)
New Revision: 78434
URL: http://svn.boost.org/trac/boost/changeset/78434
Log:
ScopedEnum: Rollback last change as there are regressions on Spirit
Text files modified:
trunk/boost/detail/scoped_enum_emulation.hpp | 271 +++++++++++++++++++++++++++++++++------
1 files changed, 227 insertions(+), 44 deletions(-)
Modified: trunk/boost/detail/scoped_enum_emulation.hpp
==============================================================================
--- trunk/boost/detail/scoped_enum_emulation.hpp (original)
+++ trunk/boost/detail/scoped_enum_emulation.hpp 2012-05-12 07:07:58 EDT (Sat, 12 May 2012)
@@ -1,40 +1,125 @@
// scoped_enum_emulation.hpp ---------------------------------------------------------//
// Copyright Beman Dawes, 2009
-// Copyright (C) 2012 Vicente J. Botet Escriba
+// Copyright (C) 2011-2012 Vicente J. Botet Escriba
// Copyright (C) 2012 Anthony Williams
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
-// Generates C++0x scoped enums if the feature is present, otherwise emulates C++0x
-// scoped enums with C++03 namespaces and enums. The Boost.Config BOOST_NO_SCOPED_ENUMS
-// macro is used to detect feature support.
-//
-// See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2347.pdf for a
-// description of the scoped enum feature. Note that the committee changed the name
-// from strongly typed enum to scoped enum.
-//
-// Caution: only the syntax is emulated; the semantics are not emulated and
-// the syntax emulation doesn't include being able to specify the underlying
-// representation type.
-//
-// The emulation is via struct rather than namespace to allow use within classes.
-// Thanks to Andrey Semashev for pointing that out.
-//
-// Helpful comments and suggestions were also made by Kjell Elster, Phil Endecott,
-// Joel Falcou, Mathias Gaunard, Felipe Magno de Almeida, Matt Calabrese, Vincente
-// Botet, and Daniel James.
-//
-// Sample usage:
-//
-// BOOST_SCOPED_ENUM_START(algae) { green, red, cyan }; BOOST_SCOPED_ENUM_END
-// ...
-// BOOST_SCOPED_ENUM(algae) sample( algae::red );
-// void foo( BOOST_SCOPED_ENUM(algae) color );
-// ...
-// sample = algae::green;
-// foo( algae::cyan );
+/*
+[section:scoped_enums Scoped Enums]
+
+Generates C++0x scoped enums if the feature is present, otherwise emulates C++0x
+scoped enums with C++03 namespaces and enums. The Boost.Config BOOST_NO_SCOPED_ENUMS
+macro is used to detect feature support.
+
+See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2347.pdf for a
+description of the scoped enum feature. Note that the committee changed the name
+from strongly typed enum to scoped enum.
+
+Some of the enumerations defined in the standard library are scoped enums.
+
+ enum class future_errc
+ {
+ broken_promise,
+ future_already_retrieved,
+ promise_already_satisfied,
+ no_state
+ };
+
+On compilers that don't support them, the library two emulations:
+
+[heading Strict]
+
+* Able to specify the underlying type.
+* explicit conversion to/from underlying type.
+* The wrapper is not a C++03 enum type.
+
+The user can declare declare these types as
+
+ BOOST_SCOPED_ENUM_DECLARE_BEGIN(future_errc)
+ {
+ broken_promise,
+ future_already_retrieved,
+ promise_already_satisfied,
+ no_state
+ }
+ BOOST_SCOPED_ENUM_DECLARE_END(future_errc)
+
+These macros allows to use 'future_errc' in almost all the cases as an scoped enum.
+
+ future_errc err = future_errc::no_state;
+
+There are however some limitations:
+
+* The type is not a C++ enum, so 'is_enum<future_errc>' will be false_type.
+* The emulated scoped enum can not be used in switch nor in template arguments. For these cases the user needs to use some macros.
+
+Instead of
+
+ switch (ev)
+ {
+ case future_errc::broken_promise:
+ // ...
+
+use
+
+ switch (boost::native_value(ev))
+ {
+ case future_errc::broken_promise:
+
+And instead of
+
+ #ifdef BOOST_NO_SCOPED_ENUMS
+ template <>
+ struct BOOST_SYMBOL_VISIBLE is_error_code_enum<future_errc> : public true_type { };
+ #endif
+
+use
+
+ #ifdef BOOST_NO_SCOPED_ENUMS
+ template <>
+ struct BOOST_SYMBOL_VISIBLE is_error_code_enum<future_errc::enum_type > : public true_type { };
+ #endif
+
+
+Sample usage:
+
+ BOOST_SCOPED_ENUM_UT_DECLARE_BEGIN(algae, char) { green, red, cyan }; BOOST_SCOPED_ENUM_DECLARE_END(algae)
+ ...
+ algae sample( algae::red );
+ void foo( algae color );
+ ...
+ sample = algae::green;
+ foo( algae::cyan );
+
+ Light
+ Caution: only the syntax is emulated; the semantics are not emulated and
+ the syntax emulation doesn't include being able to specify the underlying
+ representation type.
+
+ The literal scoped emulation is via struct rather than namespace to allow use within classes.
+ Thanks to Andrey Semashev for pointing that out.
+ However the type is an real C++03 enum and so convertible implicitly to an int.
+
+ Sample usage:
+
+ BOOST_SCOPED_ENUM_START(algae) { green, red, cyan }; BOOST_SCOPED_ENUM_END
+ ...
+ BOOST_SCOPED_ENUM(algae) sample( algae::red );
+ void foo( BOOST_SCOPED_ENUM(algae) color );
+ ...
+ sample = algae::green;
+ foo( algae::cyan );
+
+ Helpful comments and suggestions were also made by Kjell Elster, Phil Endecott,
+ Joel Falcou, Mathias Gaunard, Felipe Magno de Almeida, Matt Calabrese, Vicente
+ Botet, and Daniel James.
+
+[endsect]
+*/
+
#ifndef BOOST_SCOPED_ENUM_EMULATION_HPP
#define BOOST_SCOPED_ENUM_EMULATION_HPP
@@ -46,18 +131,61 @@
{
#ifdef BOOST_NO_SCOPED_ENUMS
+ /**
+ * Meta-function to get the underlying type of a scoped enum.
+ *
+ * Requires EnumType must be an enum type or the emulation of a scoped enum
+ */
template <typename EnumType>
struct underlying_type
{
+ /**
+ * The member typedef type names the underlying type of EnumType. It is EnumType::underlying_type when the EnumType is an emulated scoped enum,
+ * std::underlying_type<EnumType>::type when the standard library std::underlying_type is provided.
+ *
+ * The user will need to specialize it when the compiler supports scoped enums but don't provides std::underlying_type.
+ */
typedef typename EnumType::underlying_type type;
};
+ /**
+ * Meta-function to get the native enum type associated to an enum class or its emulation.
+ */
+ template <typename EnumType>
+ struct native_type
+ {
+ /**
+ * The member typedef type names the native enum type associated to the scoped enum,
+ * which is it self if the compiler supports scoped enums or EnumType::enum_type if it is an emulated scoped enum.
+ */
+ typedef typename EnumType::enum_type type;
+ };
+
+ /**
+ * Casts a scoped enum to its underlying type.
+ *
+ * This function is useful to when working with scoped enum classes which doens't implicitly convert to the underlying type.
+ * @param v A scoped enum.
+ * @returns The underlying type.
+ * @throws No-throws.
+ */
template <typename UnderlyingType, typename EnumType>
UnderlyingType underlying_cast(EnumType v)
{
return v.underlying();
}
+ /**
+ * Casts a scoped enum to its native enum type.
+ *
+ * This function is useful to make programs portable when the scoped enum emulation can not be use where native enums can.
+ *
+ * EC the scoped enum type
+ *
+ * @param v A scoped enum.
+ * @returns The native enum value.
+ * @throws No-throws.
+ */
template <typename EC>
inline
typename EC::enum_type native_value(EC e)
@@ -73,6 +201,12 @@
//typedef typename std::underlying_type<EnumType>::type type;
};
+ template <typename EnumType>
+ struct native_type
+ {
+ typedef EnumType type;
+ };
+
template <typename UnderlyingType, typename EnumType>
UnderlyingType underlying_cast(EnumType v)
{
@@ -103,43 +237,79 @@
#endif
+/**
+ * Start a declaration of a scoped enum.
+ *
+ * @param EnumType The new scoped enum.
+ * @param UnderlyingType The underlying type.
+ */
#define BOOST_SCOPED_ENUM_UT_DECLARE_BEGIN(EnumType, UnderlyingType) \
struct EnumType { \
- typedef UnderlyingType underlying_type; \
- EnumType() {} \
+ typedef UnderlyingType underlying_type; \
+ EnumType() BOOST_NOEXCEPT {} \
explicit EnumType(underlying_type v) : v_(v) {} \
underlying_type underlying() const { return v_; } \
BOOST_SCOPED_ENUM_UT_DECLARE_CONVERSION_OPERATOR \
- private: \
- underlying_type v_; \
+ private: \
+ underlying_type v_; \
typedef EnumType self_type; \
- public: \
+ public: \
enum enum_type
#define BOOST_SCOPED_ENUM_DECLARE_END2() \
- enum_type native() const { return enum_type(v_); } \
- friend bool operator ==(self_type lhs, enum_type rhs) { return enum_type(lhs.v_)==rhs; } \
- friend bool operator ==(enum_type lhs, self_type rhs) { return lhs==enum_type(rhs.v_); } \
- friend bool operator !=(self_type lhs, enum_type rhs) { return enum_type(lhs.v_)!=rhs; } \
- friend bool operator !=(enum_type lhs, self_type rhs) { return lhs!=enum_type(rhs.v_); } \
+ enum_type native() const BOOST_NOEXCEPT { return enum_type(v_); } \
+ operator enum_type() const BOOST_NOEXCEPT { return native(); } \
+ friend bool operator ==(self_type lhs, self_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)==enum_type(rhs.v_); } \
+ friend bool operator ==(self_type lhs, enum_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)==rhs; } \
+ friend bool operator ==(enum_type lhs, self_type rhs) BOOST_NOEXCEPT { return lhs==enum_type(rhs.v_); } \
+ friend bool operator !=(self_type lhs, self_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)!=enum_type(rhs.v_); } \
+ friend bool operator !=(self_type lhs, enum_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)!=rhs; } \
+ friend bool operator !=(enum_type lhs, self_type rhs) BOOST_NOEXCEPT { return lhs!=enum_type(rhs.v_); } \
+ friend bool operator <(self_type lhs, self_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)<enum_type(rhs.v_); } \
+ friend bool operator <(self_type lhs, enum_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)<rhs; } \
+ friend bool operator <(enum_type lhs, self_type rhs) BOOST_NOEXCEPT { return lhs<enum_type(rhs.v_); } \
+ friend bool operator <=(self_type lhs, self_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)<=enum_type(rhs.v_); } \
+ friend bool operator <=(self_type lhs, enum_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)<=rhs; } \
+ friend bool operator <=(enum_type lhs, self_type rhs) BOOST_NOEXCEPT { return lhs<=enum_type(rhs.v_); } \
+ friend bool operator >(self_type lhs, self_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)>enum_type(rhs.v_); } \
+ friend bool operator >(self_type lhs, enum_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)>rhs; } \
+ friend bool operator >(enum_type lhs, self_type rhs) BOOST_NOEXCEPT { return lhs>enum_type(rhs.v_); } \
+ friend bool operator >=(self_type lhs, self_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)>=enum_type(rhs.v_); } \
+ friend bool operator >=(self_type lhs, enum_type rhs) BOOST_NOEXCEPT { return enum_type(lhs.v_)>=rhs; } \
+ friend bool operator >=(enum_type lhs, self_type rhs) BOOST_NOEXCEPT { return lhs>=enum_type(rhs.v_); } \
};
#define BOOST_SCOPED_ENUM_DECLARE_END(EnumType) \
; \
- EnumType(enum_type v) : v_(v) {} \
+ EnumType(enum_type v) BOOST_NOEXCEPT : v_(v) {} \
BOOST_SCOPED_ENUM_DECLARE_END2()
+/**
+ * Starts a declaration of a scoped enum with the default int underlying type.
+ *
+ * @param EnumType The new scoped enum.
+ */
#define BOOST_SCOPED_ENUM_DECLARE_BEGIN(EnumType) \
BOOST_SCOPED_ENUM_UT_DECLARE_BEGIN(EnumType,int)
+/**
+ * Name of the native enum type.
+ *
+ * @param NT The new scoped enum.
+ */
#define BOOST_SCOPED_ENUM_NATIVE(EnumType) EnumType::enum_type
+/**
+ * Forward declares an scoped enum.
+ *
+ * @param NT The scoped enum.
+ */
#define BOOST_SCOPED_ENUM_FORWARD_DECLARE(EnumType) struct EnumType
#else // BOOST_NO_SCOPED_ENUMS
#define BOOST_SCOPED_ENUM_UT_DECLARE_BEGIN(EnumType,UnderlyingType) enum class EnumType:UnderlyingType
#define BOOST_SCOPED_ENUM_DECLARE_BEGIN(EnumType) enum class EnumType
-#define BOOST_SCOPED_ENUM_DECLARE_END2()
+#define BOOST_SCOPED_ENUM_DECLARE_END2()
#define BOOST_SCOPED_ENUM_DECLARE_END(EnumType) ;
#define BOOST_SCOPED_ENUM_NATIVE(EnumType) EnumType
@@ -147,8 +317,21 @@
#endif // BOOST_NO_SCOPED_ENUMS
-#define BOOST_SCOPED_ENUM_START(name) BOOST_SCOPED_ENUM_DECLARE_BEGIN(name)
-#define BOOST_SCOPED_ENUM_END BOOST_SCOPED_ENUM_DECLARE_END2()
-#define BOOST_SCOPED_ENUM(name) BOOST_SCOPED_ENUM_NATIVE(name)
+//#define BOOST_SCOPED_ENUM_START(name) BOOST_SCOPED_ENUM_DECLARE_BEGIN(name)
+//#define BOOST_SCOPED_ENUM_END BOOST_SCOPED_ENUM_DECLARE_END2()
+//#define BOOST_SCOPED_ENUM(name) BOOST_SCOPED_ENUM_NATIVE(name)
+
+#ifdef BOOST_NO_SCOPED_ENUMS
+
+# define BOOST_SCOPED_ENUM_START(name) struct name { enum enum_type
+# define BOOST_SCOPED_ENUM_END };
+# define BOOST_SCOPED_ENUM(name) name::enum_type
+
+#else
+
+# define BOOST_SCOPED_ENUM_START(name) enum class name
+# define BOOST_SCOPED_ENUM_END
+# define BOOST_SCOPED_ENUM(name) name
+#endif
#endif // BOOST_SCOPED_ENUM_EMULATION_HPP