diff --git a/doc/optional.html b/doc/optional.html index 895312d..61a29c5 100644 --- a/doc/optional.html +++ b/doc/optional.html @@ -3,7 +3,6 @@ - @@ -324,6 +323,8 @@ class optional optional ( T const& v ) ; + optional ( bool condition, T const& v ) ; [new in 1.34] + optional ( optional const& rhs ) ; template<class U> explicit optional ( optional<U> const& rhs ) ; @@ -347,6 +348,8 @@ class optional T const& get() const ; T& get() ; + T const& get_value_or( T const& default ) const ; [new in 1.34] + T const* operator ->() const ; T* operator ->() ; @@ -380,6 +383,12 @@ template<class T> inline bool operator <= ( optional<T> const& x, op template<class T> inline bool operator >= ( optional<T> const& x, optional<T> const& y ) ; +template<class T> inline optional<T> make_optional ( T const& v ) ; [new in 1.34] + +template<class T> inline optional<T> make_optional ( bool condition, T const& v ) ; [new in 1.34] + +template<class T> inline T const& get_optional_value_or ( optional<T> const& opt, T const& default ) ; [new in 1.34] + template<class T> inline T const& get ( optional<T> const& opt ) ; template<class T> inline T& get ( optional<T> & opt ) ; @@ -436,7 +445,7 @@ assert ( !def ) ; 
optional<T>::optional( none_t );
-

Effect: Constructs an optional uninitialized.

+

Effect: Constructs an optional uninitialized.

Postconditions: *this is uninitialized.

Throws: Nothing.

Notes:

@@ -459,7 +468,6 @@ assert ( !n ) ; 
optional<T (not a ref)>::optional( T const& v )

Effect: Directly-Constructs an optional.

-

Postconditions: *this is initialized and its value is a copy of 'v'.

Throws: Whatever T::T( T const& ) throws.

Notes: T::T( T const& ) is called.

@@ -495,6 +503,23 @@ assert (*opt == v);
+
optional<T (not a ref)>::optional( bool condition, T const& v ) ;
+optional<T&>           ::optional( bool condition, T&       v ) ;
+
+ +
+

If condition is true, same as:

+
optional<T (not a ref)>::optional( T const& v )
+optional<T&>           ::optional( T&       v )
+
+

otherwise, same as:

+
optional<T (not a ref)>::optional()
+optional<T&>           ::optional()
+
+
+ +
+ 
optional<T (not a ref)>::optional( optional const& rhs );

Effect: Copy-Constructs an optional.

@@ -797,7 +822,6 @@ assert ( *opt1 == static_cast<U>(v) ) ;
- 
T const& optional<T (not a ref)>::operator*() const ;
 T&       optional<T (not a ref)>::operator*();
@@ -828,6 +852,32 @@ assert ( *opt == w ) ;
+
T const& optional<T (not a ref)>::get_value_or( T const& default) const ;
+T&       optional<T (not a ref)>::get_value_or( T&       default ) ;
+
+inline T const& get_optional_value_or ( optional<T (not a ref)> const& o, T const& default ) ;
+inline T&       get_optional_value_or ( optional<T (not a ref)>&       o, T&       default ) ;
+
+
+

Returns: A reference to the contained value, if any, or default

+

Throws: Nothing.

+

Example:

+
+ 
T v, z ;
+optional<T> def;
+T const& y = def.get_value_or(z);
+assert ( y == z ) ;
+
+optional<T> opt ( v );
+T const& u = get_optional_value_or(opt,z);
+assert ( u == v ) ;
+assert ( u != z ) ;
+
+
+ 

+

+

+
 
 
T const& optional<T&>::operator*() const ;
 T      & optional<T&>::operator*();

@@ -965,18 +1015,47 @@ assert ( opt.is_initialized() );
 
 

 
+
optional<T (not a ref)> make_optional( T const& v )

+

+
Returns: optional<T>(v) for the deduced type T of v.

+
Example:

+

+
template<class T> void foo ( optional<T> const& opt ) ;
+
+foo ( make_optional(1+1) ) ; // Creates an optional<int>
+

+

+

+
+
optional<T (not a ref)> make_optional( bool condition, T const& v )

+

+
Returns: optional<T>(condition,v) for the deduced type T of v.

+
Example:

+

+
optional<double> calculate_foo()
+{
+  double val = compute_foo();
+  return make_optional(is_not_nan_and_finite(val),val);
+}
+
+optional<double> v = calculate_foo();
+if ( !v )
+  error("foo wasn't computed");
+

+

+
+

+
 
 
bool operator == ( optional<T> const& x, optional<T> const& y );

 

 
Returns: If both x and y are initialied, (*x == *y).
-If only x or y is initialized, false. If both are uninitialized, true.
-

+If only x or y is initialized, false. If both are uninitialized, true. 

 
Throws: Nothing.

 
Notes: Pointers have shallow relational operators while optional has
 deep relational operators. Do not use operator == directly in generic code
 which expect to be given either an optional<T> or a pointer;
-use equal_pointees() instead
-

+use equal_pointees() instead 

 
Example:

 

     
T x(12);
@@ -1012,14 +1091,12 @@ assert ( optX != optZ ) ;
 

 
Returns: If y is not initialized, false.
 If y is initialized and x is not initialized, true.
-If both x and y are initialized, (*x < *y).
-

+If both x and y are initialized, (*x < *y). 

 
Throws: Nothing.

 
Notes: Pointers have shallow relational operators while optional has
 deep relational operators. Do not use operator < directly in generic code
 which expect to be given either an optional<T> or a pointer;
-use less_pointees() instead
-

+use less_pointees() instead 

 
Example:

 

     
T x(12);
@@ -1082,23 +1159,17 @@ assert ( optX != optZ ) ;
 
void swap ( optional<T>& x, optional<T>& y );

 
 

-
Effect: If both x and y are initialized, calls swap(*x,*y)
-using std::swap.

+
Effect: If both x and y are initialized, calls swap(*x,*y) using std::swap.

 If only one is initialized, say x, calls: y.reset(*x); x.reset();

-If none is initialized, does nothing.
-

+If none is initialized, does nothing. 

 
Postconditions: The states of x and y interchanged.

 
Throws: If both are initialized, whatever swap(T&,T&) throws.
-If only one is initialized, whatever T::T ( T const& ) throws.
-

-
Notes: If both are initialized, swap(T&,T&) is used unqualified
-but with std::swap introduced in scope.

-If only one is initialized, T::~T() and T::T( T const& ) is called.
-

+If only one is initialized, whatever T::T ( T const& ) throws. 

+
Notes: If both are initialized, swap(T&,T&) is used unqualified but with std::swap introduced in scope.

+If only one is initialized, T::~T() and T::T( T const& ) is called. 

 
Exception Safety: If both are initialized, this operation has the exception
 safety guarantees of swap(T&,T&).

-If only one is initialized, it has the same basic guarantee as optional<T>::reset( T const& ).
-

+If only one is initialized, it has the same basic guarantee as optional<T>::reset( T const& ). 

 
Example:

 

       
T x(12);
@@ -1254,8 +1325,7 @@ assert(a==b);
 b = 3 ;
 assert(ra!=b); // 'ra' is not rebound to 'b'
 

-
Now, if you assign to an initialized optional<T&>, the effect is to 
-rebind to the new object instead of assigning the referee. This is unlike 
+
Now, if you assign to an initialized optional<T&>, the effect is to rebind to the new object instead of assigning the referee. This is unlike 
 bare C++ references.

 
int a = 1 ;
 int b = 2 ;
@@ -1358,8 +1428,7 @@ public:
 

 
A limitation of this method is that it doesn't scale well to wrapped objects with multiple
 constructors nor to generic code were the constructor overloads are unknown.

-
The solution presented in this library is the family of InPlaceFactories and
-TypedInPlaceFactories.

+
The solution presented in this library is the family of InPlaceFactories and TypedInPlaceFactories.

 These factories are a family of classes which encapsulate an increasing number of arbitrary
 constructor parameters and supply a method to construct an object of a given type using those
 parameters at an address specified by the user via placement new.

@@ -1427,10 +1496,7 @@ public:
   W ( in_place(123,"hello") ) ;
 }
 

-
The factories are implemented in the headers:
-in_place_factory.hpp and
-typed_in_place_factory.hpp
-

+
The factories are implemented in the headers: in_place_factory.hpp and typed_in_place_factory.hpp 

 
 

 
@@ -1473,8 +1539,7 @@ of the assignment methods:

   TypedInPlaceFactory const& ) 
   
  •  optional<T>:::reset ( T const&)
    • 
 
-
    Can only guarantee the basic exception safety: The lvalue optional is left uninitialized
-if an exception is thrown (any previous value is first destroyed using T::~T())
    
+
    Can only guarantee the basic exception safety: The lvalue optional is left uninitialized if an exception is thrown (any previous value is first destroyed using T::~T())
    
 
    On the other hand, the uninitializing methods:
    
 
    
 
\ No newline at end of file
diff --git a/include/boost/optional/optional.hpp b/include/boost/optional/optional.hpp
index 4421f4a..8a78a40 100644
--- a/include/boost/optional/optional.hpp
+++ b/include/boost/optional/optional.hpp
@@ -185,6 +185,16 @@ class optional_base : public optional_tag
     {
       construct(val);
     }
+    
+    // Creates an optional initialized with 'val' IFF cond is true, otherwise creates an uninitialzed optional.
+    // Can throw if T::T(T const&) does
+    optional_base ( bool cond, argument_type val )
+      :
+      m_initialized(false)
+    {
+      if ( cond )
+        construct(val);
+    }
 
     // Creates a deep copy of another optional
     // Can throw if T::T(T const&) does
@@ -455,6 +465,9 @@ class optional : public optional_detail::optional_base
     // Can throw if T::T(T const&) does
     optional ( argument_type val ) : base(val) {}
 
+    // Creates an optional initialized with 'val' IFF cond is true, otherwise creates an uninitialized optional.
+    // Can throw if T::T(T const&) does
+    optional ( bool cond, argument_type val ) : base(cond,val) {}
 
 #ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR
     // NOTE: MSVC needs templated versions first
@@ -549,6 +562,10 @@ class optional : public optional_detail::optional_base
     reference_const_type get() const { BOOST_ASSERT(this->is_initialized()) ; return this->get_impl(); }
     reference_type       get()       { BOOST_ASSERT(this->is_initialized()) ; return this->get_impl(); }
 
+    // Returns a copy of the value if this is initialized, 'v' otherwise
+    reference_const_type get_value_or ( reference_const_type v ) const { return this->is_initialized() ? get() : v ; }
+    reference_type       get_value_or ( reference_type       v )       { return this->is_initialized() ? get() : v ; }
+    
     // Returns a pointer to the value if this is initialized, otherwise,
     // the behaviour is UNDEFINED
     // No-throw
@@ -570,6 +587,22 @@ class optional : public optional_detail::optional_base
        bool operator!() const { return !this->is_initialized() ; }
 } ;
 
+// Returns optional(v)
+template 
+inline 
+optional make_optional ( T const& v  )
+{
+  return optional(v);
+}
+
+// Returns optional(cond,v)
+template 
+inline 
+optional make_optional ( bool cond, T const& v )
+{
+  return optional(cond,v);
+}
+
 // Returns a reference to the value if this is initialized, otherwise, the behaviour is UNDEFINED.
 // No-throw
 template
@@ -606,6 +639,24 @@ get ( optional* opt )
   return opt->get_ptr() ;
 }
 
+// Returns a reference to the value if this is initialized, otherwise, the behaviour is UNDEFINED.
+// No-throw
+template
+inline
+BOOST_DEDUCED_TYPENAME optional::reference_const_type
+get_optional_value_or ( optional const& opt, BOOST_DEDUCED_TYPENAME optional::reference_const_type v )
+{
+  return opt.get_value_or(v) ;
+}
+
+template
+inline
+BOOST_DEDUCED_TYPENAME optional::reference_type
+get_optional_value_or ( optional& opt, BOOST_DEDUCED_TYPENAME optional::reference_type v )
+{
+  return opt.get_value_or(v) ;
+}
+
 // Returns a pointer to the value if this is initialized, otherwise, returns NULL.
 // No-throw
 template
@@ -767,10 +818,6 @@ template inline void swap ( optional& x, optional& y )
   optional_detail::optional_swap(x,y);
 }
 
-template inline optional make_optional ( T const& v )
-{
-  return optional(v);
-}
 
 } // namespace boost
 
diff --git a/test/optional_test.cpp b/test/optional_test.cpp
index 12dda2a..5c10eed 100644
--- a/test/optional_test.cpp
+++ b/test/optional_test.cpp
@@ -15,7 +15,9 @@
 
 #define BOOST_ENABLE_ASSERT_HANDLER
 
-#include "boost/optional.hpp"
+#include "boost/bind/apply.hpp" // Included just to test proper interaction with boost::apply<> as reported by Daniel Wallin
+
+#include "boost/optional/optional.hpp"
 
 #ifdef __BORLANDC__
 #pragma hdrstop
@@ -151,6 +153,95 @@ void test_basics( T const* )
   ob.reset();
   check_is_pending_dtor( ARG(T) ) ;
   check_uninitialized(ob);
+  
+}
+
+template
+void test_conditional_ctor_and_get_valur_or ( T const* )
+{
+  TRACE( std::endl << BOOST_CURRENT_FUNCTION  );
+  
+  T a(321);
+  
+  T z(123);
+  
+  optional const cdef0(false,a);
+  
+  optional def0(false,a);
+  optional def1 = boost::make_optional(false,a); //  T is not within boost so ADL won't find make_optional unqualified
+  check_uninitialized(def0);
+  check_uninitialized(def1);
+
+  optional const co0(true,a);
+  
+  optional o0(true,a);
+  optional o1 = boost::make_optional(true,a); //  T is not within boost so ADL won't find make_optional unqualified
+
+  check_initialized(o0);
+  check_initialized(o1);
+  check_value(o0,a,z);
+  check_value(o1,a,z);
+  
+  T b = def0.get_value_or(z);
+  BOOST_CHECK( b == z ) ;
+  
+  b = get_optional_value_or(def0,z);
+  BOOST_CHECK( b == z ) ;
+  
+  b = o0.get_value_or(z);
+  BOOST_CHECK( b == a ) ;
+
+  b = get_optional_value_or(o0,z);
+  BOOST_CHECK( b == a ) ;
+  
+  
+  T const& crz = z ;
+  T&        rz = z ;
+  
+  T const& crzz = def0.get_value_or(crz);
+  BOOST_CHECK( crzz == crz ) ;
+  
+  T& rzz = def0.get_value_or(rz);
+  BOOST_CHECK( rzz == rz ) ;
+  
+  T const& crzzz = get_optional_value_or(cdef0,crz);
+  BOOST_CHECK( crzzz == crz ) ;
+  
+  T& rzzz = get_optional_value_or(def0,rz);
+  BOOST_CHECK( rzzz == rz ) ;
+  
+  T const& crb = o0.get_value_or(crz);
+  BOOST_CHECK( crb == a ) ;
+  
+  T& rb = o0.get_value_or(rz);
+  BOOST_CHECK( rb == b ) ;
+  
+  T const& crbb = get_optional_value_or(co0,crz);
+  BOOST_CHECK( crbb == b ) ;
+  
+  T const& crbbb = get_optional_value_or(o0,crz);
+  BOOST_CHECK( crbbb == b ) ;
+  
+  T& rbb = get_optional_value_or(o0,rz);
+  BOOST_CHECK( rbb == b ) ;
+  
+  T& ra = a ;
+  
+  optional defref(false,ra);
+  BOOST_CHECK(!defref);
+  
+  optional ref(true,ra);
+  BOOST_CHECK(!!ref);
+  
+  a = T(432);
+  
+  BOOST_CHECK( *ref == a ) ;
+  
+  T& r1 = defref.get_value_or(z);
+  BOOST_CHECK( r1 == z ) ;
+  
+  T& r2 = ref.get_value_or(z);
+  BOOST_CHECK( r2 == a ) ;
 }
 
 //
@@ -688,6 +779,7 @@ void test_with_builtin_types()
   TRACE( std::endl << BOOST_CURRENT_FUNCTION   );
 
   test_basics( ARG(double) );
+  test_conditional_ctor_and_get_valur_or( ARG(double) );
   test_uninitialized_access( ARG(double) );
   test_no_throwing_swap( ARG(double) );
   test_relops( ARG(double) ) ;
@@ -699,6 +791,7 @@ void test_with_class_type()
   TRACE( std::endl << BOOST_CURRENT_FUNCTION   );
 
   test_basics( ARG(X) );
+  test_conditional_ctor_and_get_valur_or( ARG(X) );
   test_direct_value_manip( ARG(X) );
   test_uninitialized_access( ARG(X) );
   test_throwing_direct_init( ARG(X) );