[Boost-commit] svn:boost r78434 - trunk/boost/detail

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