// { dg-options "-std=gnu++0x" }
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// { dg-options "-std=gnu++0x" }
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// { dg-do "run" }
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// { dg-do "run" }
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// A basic implementation of TR1's bind using variadic teplates
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// A basic implementation of TR1's bind using variadic teplates
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// Contributed by Douglas Gregor
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// Contributed by Douglas Gregor
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#include
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#include
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|
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// Trivial reference_wrapper
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// Trivial reference_wrapper
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template
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template
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struct reference_wrapper
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struct reference_wrapper
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{
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{
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reference_wrapper(T& x) : ptr(&x) { }
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reference_wrapper(T& x) : ptr(&x) { }
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|
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operator T&() const { return *ptr; }
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operator T&() const { return *ptr; }
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|
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T& get() const { return *ptr; }
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T& get() const { return *ptr; }
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|
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T* ptr;
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T* ptr;
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};
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};
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|
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template reference_wrapper ref(T& x) { return x; }
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template reference_wrapper ref(T& x) { return x; }
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template reference_wrapper cref(const T& x) { return x; }
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template reference_wrapper cref(const T& x) { return x; }
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|
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// Simple type-traits we'll need
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// Simple type-traits we'll need
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template
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template
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struct add_reference
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struct add_reference
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{
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{
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typedef T& type;
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typedef T& type;
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};
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};
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|
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template
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template
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struct add_reference
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struct add_reference
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{
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{
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typedef T& type;
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typedef T& type;
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};
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};
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|
|
template
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template
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struct is_same
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struct is_same
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{
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{
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static const bool value = false;
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static const bool value = false;
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};
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};
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|
|
template
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template
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struct is_same
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struct is_same
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{
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{
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static const bool value = true;
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static const bool value = true;
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};
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};
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|
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// For creating the constructor parameters of tuple<>
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// For creating the constructor parameters of tuple<>
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template
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template
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struct add_const_reference
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struct add_const_reference
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{
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{
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typedef const T& type;
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typedef const T& type;
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};
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};
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|
|
template
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template
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struct add_const_reference
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struct add_const_reference
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{
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{
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typedef T& type;
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typedef T& type;
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};
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};
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|
|
// 6.1.3 Class template tuple: Needed for bind() implementation
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// 6.1.3 Class template tuple: Needed for bind() implementation
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template
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template
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class tuple;
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class tuple;
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template<> class tuple<> { };
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template<> class tuple<> { };
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|
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template
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template
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class tuple
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class tuple
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: private tuple
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: private tuple
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{
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{
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typedef tuple inherited;
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typedef tuple inherited;
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|
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public:
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public:
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tuple() { }
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tuple() { }
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|
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// implicit copy-constructor is okay
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// implicit copy-constructor is okay
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|
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tuple(typename add_const_reference::type v,
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tuple(typename add_const_reference::type v,
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typename add_const_reference::type... vtail)
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typename add_const_reference::type... vtail)
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: m_head(v), inherited(vtail...) { }
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: m_head(v), inherited(vtail...) { }
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|
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template
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template
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tuple(const tuple& other)
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tuple(const tuple& other)
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: m_head(other.head()), inherited(other.tail()) { }
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: m_head(other.head()), inherited(other.tail()) { }
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|
|
template
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template
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tuple& operator=(const tuple& other)
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tuple& operator=(const tuple& other)
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{
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{
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m_head = other.head();
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m_head = other.head();
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tail() = other.tail();
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tail() = other.tail();
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return *this;
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return *this;
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}
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}
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|
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typename add_reference::type head() { return m_head; }
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typename add_reference::type head() { return m_head; }
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typename add_reference::type head() const { return m_head; }
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typename add_reference::type head() const { return m_head; }
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inherited& tail() { return *this; }
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inherited& tail() { return *this; }
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const inherited& tail() const { return *this; }
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const inherited& tail() const { return *this; }
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|
|
protected:
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protected:
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Head m_head;
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Head m_head;
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};
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};
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|
|
template
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template
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struct make_tuple_result
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struct make_tuple_result
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{
|
{
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typedef T type;
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typedef T type;
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};
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};
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|
|
template
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template
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struct make_tuple_result >
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struct make_tuple_result >
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{
|
{
|
typedef T& type;
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typedef T& type;
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};
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};
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|
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// 6.1.3.2 Tuple creation functions
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// 6.1.3.2 Tuple creation functions
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struct ignore_t {
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struct ignore_t {
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template ignore_t& operator=(const T&) { return *this; }
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template ignore_t& operator=(const T&) { return *this; }
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} ignore;
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} ignore;
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|
|
template
|
template
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tuple::type...>
|
tuple::type...>
|
make_tuple(const Values&... values)
|
make_tuple(const Values&... values)
|
{
|
{
|
return tuple::type...>(values...);
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return tuple::type...>(values...);
|
}
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}
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|
|
template
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template
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tuple tie(Values&... values)
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tuple tie(Values&... values)
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{
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{
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return tuple(values...);
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return tuple(values...);
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}
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}
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|
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// 6.1.3.3 Tuple helper classes
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// 6.1.3.3 Tuple helper classes
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template
|
template
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struct tuple_size;
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struct tuple_size;
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|
|
template<>
|
template<>
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struct tuple_size >
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struct tuple_size >
|
{
|
{
|
static const __SIZE_TYPE__ value = 0;
|
static const __SIZE_TYPE__ value = 0;
|
};
|
};
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|
|
template
|
template
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struct tuple_size >
|
struct tuple_size >
|
{
|
{
|
static const __SIZE_TYPE__ value = 1 + tuple_size >::value;
|
static const __SIZE_TYPE__ value = 1 + tuple_size >::value;
|
};
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};
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|
|
template
|
template
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struct tuple_element;
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struct tuple_element;
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|
|
template
|
template
|
struct tuple_element >
|
struct tuple_element >
|
{
|
{
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typedef typename tuple_element >::type type;
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typedef typename tuple_element >::type type;
|
};
|
};
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|
|
template
|
template
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struct tuple_element<0, tuple >
|
struct tuple_element<0, tuple >
|
{
|
{
|
typedef Head type;
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typedef Head type;
|
};
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};
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|
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// 6.1.3.4 Element access
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// 6.1.3.4 Element access
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template
|
template
|
class get_impl;
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class get_impl;
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|
|
template
|
template
|
class get_impl >
|
class get_impl >
|
{
|
{
|
typedef typename tuple_element >::type Element;
|
typedef typename tuple_element >::type Element;
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typedef typename add_reference::type RJ;
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typedef typename add_reference::type RJ;
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typedef typename add_const_reference::type PJ;
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typedef typename add_const_reference::type PJ;
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typedef get_impl > Next;
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typedef get_impl > Next;
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|
|
public:
|
public:
|
static RJ get(tuple& t)
|
static RJ get(tuple& t)
|
{ return Next::get(t.tail()); }
|
{ return Next::get(t.tail()); }
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|
|
static PJ get(const tuple& t)
|
static PJ get(const tuple& t)
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{ return Next::get(t.tail()); }
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{ return Next::get(t.tail()); }
|
};
|
};
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|
|
template
|
template
|
class get_impl<0, tuple >
|
class get_impl<0, tuple >
|
{
|
{
|
typedef typename add_reference::type RJ;
|
typedef typename add_reference::type RJ;
|
typedef typename add_const_reference::type PJ;
|
typedef typename add_const_reference::type PJ;
|
|
|
public:
|
public:
|
static RJ get(tuple& t) { return t.head(); }
|
static RJ get(tuple& t) { return t.head(); }
|
static PJ get(const tuple& t) { return t.head(); }
|
static PJ get(const tuple& t) { return t.head(); }
|
};
|
};
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|
|
template
|
template
|
typename add_reference<
|
typename add_reference<
|
typename tuple_element >::type
|
typename tuple_element >::type
|
>::type
|
>::type
|
get(tuple& t)
|
get(tuple& t)
|
{
|
{
|
return get_impl >::get(t);
|
return get_impl >::get(t);
|
}
|
}
|
|
|
template
|
template
|
typename add_const_reference<
|
typename add_const_reference<
|
typename tuple_element >::type
|
typename tuple_element >::type
|
>::type
|
>::type
|
get(const tuple& t)
|
get(const tuple& t)
|
{
|
{
|
return get_impl >::get(t);
|
return get_impl >::get(t);
|
}
|
}
|
|
|
// 6.1.3.5 Relational operators
|
// 6.1.3.5 Relational operators
|
inline bool operator==(const tuple<>&, const tuple<>&) { return true; }
|
inline bool operator==(const tuple<>&, const tuple<>&) { return true; }
|
|
|
template
|
template
|
bool operator==(const tuple& t, const tuple& u)
|
bool operator==(const tuple& t, const tuple& u)
|
{
|
{
|
return t.head() == u.head() && t.tail() == u.tail();
|
return t.head() == u.head() && t.tail() == u.tail();
|
}
|
}
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|
|
template
|
template
|
bool operator!=(const tuple& t, const tuple& u)
|
bool operator!=(const tuple& t, const tuple& u)
|
{
|
{
|
return !(t == u);
|
return !(t == u);
|
}
|
}
|
|
|
inline bool operator<(const tuple<>&, const tuple<>&) { return false; }
|
inline bool operator<(const tuple<>&, const tuple<>&) { return false; }
|
|
|
template
|
template
|
bool operator<(const tuple& t, const tuple& u)
|
bool operator<(const tuple& t, const tuple& u)
|
{
|
{
|
return (t.head() < u.head() ||
|
return (t.head() < u.head() ||
|
(!(t.head() < u.head()) && t.tail() < u.tail()));
|
(!(t.head() < u.head()) && t.tail() < u.tail()));
|
}
|
}
|
|
|
template
|
template
|
bool operator>(const tuple& t, const tuple& u)
|
bool operator>(const tuple& t, const tuple& u)
|
{
|
{
|
return u < t;
|
return u < t;
|
}
|
}
|
|
|
template
|
template
|
bool operator<=(const tuple& t, const tuple& u)
|
bool operator<=(const tuple& t, const tuple& u)
|
{
|
{
|
return !(u < t);
|
return !(u < t);
|
}
|
}
|
|
|
template
|
template
|
bool operator>=(const tuple& t, const tuple& u)
|
bool operator>=(const tuple& t, const tuple& u)
|
{
|
{
|
return !(t < u);
|
return !(t < u);
|
}
|
}
|
|
|
// enable_if, the breakfast of champions
|
// enable_if, the breakfast of champions
|
template
|
template
|
struct enable_if {
|
struct enable_if {
|
typedef Type type;
|
typedef Type type;
|
};
|
};
|
|
|
template
|
template
|
struct enable_if { };
|
struct enable_if { };
|
|
|
// 3.6 Function object binders
|
// 3.6 Function object binders
|
|
|
// 3.6.1 Class template is_bind_expression
|
// 3.6.1 Class template is_bind_expression
|
template
|
template
|
struct is_bind_expression {
|
struct is_bind_expression {
|
static const bool value = false;
|
static const bool value = false;
|
};
|
};
|
|
|
// 3.6.2 Class template is_placeholder
|
// 3.6.2 Class template is_placeholder
|
template
|
template
|
struct is_placeholder {
|
struct is_placeholder {
|
static const int value = 0;
|
static const int value = 0;
|
};
|
};
|
|
|
// 3.6.3 Function template bind
|
// 3.6.3 Function template bind
|
template struct placeholder {} ;
|
template struct placeholder {} ;
|
|
|
template struct int_c { };
|
template struct int_c { };
|
|
|
// A tuple of integer values
|
// A tuple of integer values
|
template struct int_tuple {};
|
template struct int_tuple {};
|
|
|
// make_indexes_impl is a helper for make_indexes
|
// make_indexes_impl is a helper for make_indexes
|
template
|
template
|
struct make_indexes_impl;
|
struct make_indexes_impl;
|
|
|
|
|
template
|
template
|
struct make_indexes_impl, T, Types...>
|
struct make_indexes_impl, T, Types...>
|
{
|
{
|
typedef typename make_indexes_impl
|
typedef typename make_indexes_impl
|
int_tuple,
|
int_tuple,
|
Types...>::type type;
|
Types...>::type type;
|
};
|
};
|
|
|
template
|
template
|
struct make_indexes_impl > {
|
struct make_indexes_impl > {
|
typedef int_tuple type;
|
typedef int_tuple type;
|
};
|
};
|
|
|
// make_indexes takes a variable-length number of N types and
|
// make_indexes takes a variable-length number of N types and
|
// generates an int_tuple that contains <0, 1, 2, ..., N-1>. These can
|
// generates an int_tuple that contains <0, 1, 2, ..., N-1>. These can
|
// be used as indexes for tuple's get or tuple_element operation.
|
// be used as indexes for tuple's get or tuple_element operation.
|
template
|
template
|
struct make_indexes : make_indexes_impl<0, int_tuple<>, Types...> { };
|
struct make_indexes : make_indexes_impl<0, int_tuple<>, Types...> { };
|
|
|
// Get the Ith tuple element, but only if I is in bounds.
|
// Get the Ith tuple element, but only if I is in bounds.
|
template
|
template
|
struct safe_tuple_element{ };
|
struct safe_tuple_element{ };
|
|
|
template
|
template
|
struct safe_tuple_element,
|
struct safe_tuple_element,
|
typename enable_if<(I >= 0 &&
|
typename enable_if<(I >= 0 &&
|
I < tuple_size >::value)
|
I < tuple_size >::value)
|
>::type>
|
>::type>
|
{
|
{
|
typedef typename tuple_element >::type type;
|
typedef typename tuple_element >::type type;
|
};
|
};
|
|
|
// mu maps a bound argument to an actual argument, given a tuple of
|
// mu maps a bound argument to an actual argument, given a tuple of
|
// the arguments passed to the function object returned by bind().
|
// the arguments passed to the function object returned by bind().
|
|
|
// Return the stored reference from reference_wrapper
|
// Return the stored reference from reference_wrapper
|
template
|
template
|
inline T& mu(reference_wrapper& bound_arg, const tuple&)
|
inline T& mu(reference_wrapper& bound_arg, const tuple&)
|
{
|
{
|
return bound_arg.get();
|
return bound_arg.get();
|
}
|
}
|
|
|
// Unwrap a tuple into separate arguments and forward to the function
|
// Unwrap a tuple into separate arguments and forward to the function
|
// object f.
|
// object f.
|
template
|
template
|
inline typename F::result_type
|
inline typename F::result_type
|
unwrap_and_forward(F& f, int_tuple, const tuple& args)
|
unwrap_and_forward(F& f, int_tuple, const tuple& args)
|
{
|
{
|
return f(get(args)...);
|
return f(get(args)...);
|
}
|
}
|
|
|
// Evaluate the inner bind expression
|
// Evaluate the inner bind expression
|
template
|
template
|
inline typename enable_if::value,
|
inline typename enable_if::value,
|
typename Bound::result_type>::type
|
typename Bound::result_type>::type
|
mu(Bound& bound_arg, const tuple& args)
|
mu(Bound& bound_arg, const tuple& args)
|
{
|
{
|
typedef typename make_indexes::type Indexes;
|
typedef typename make_indexes::type Indexes;
|
return unwrap_and_forward(bound_arg, Indexes(), args);
|
return unwrap_and_forward(bound_arg, Indexes(), args);
|
}
|
}
|
|
|
// Retrieve the Ith argument from args
|
// Retrieve the Ith argument from args
|
template
|
template
|
inline typename safe_tuple_element::value - 1,
|
inline typename safe_tuple_element::value - 1,
|
tuple >::type
|
tuple >::type
|
mu(Bound& bound_arg, const tuple& args)
|
mu(Bound& bound_arg, const tuple& args)
|
{
|
{
|
return get::value-1>(args);
|
return get::value-1>(args);
|
}
|
}
|
|
|
// Return the stored value.
|
// Return the stored value.
|
template
|
template
|
struct is_reference_wrapper {
|
struct is_reference_wrapper {
|
static const bool value = false;
|
static const bool value = false;
|
};
|
};
|
|
|
template
|
template
|
struct is_reference_wrapper > {
|
struct is_reference_wrapper > {
|
static const bool value = true;
|
static const bool value = true;
|
};
|
};
|
|
|
template
|
template
|
inline typename enable_if<(!is_bind_expression::value
|
inline typename enable_if<(!is_bind_expression::value
|
&& !is_placeholder::value
|
&& !is_placeholder::value
|
&& !is_reference_wrapper::value),
|
&& !is_reference_wrapper::value),
|
Bound&>::type
|
Bound&>::type
|
mu(Bound& bound_arg, const tuple&)
|
mu(Bound& bound_arg, const tuple&)
|
{
|
{
|
return bound_arg;
|
return bound_arg;
|
}
|
}
|
|
|
//
|
//
|
template
|
template
|
typename F::result_type
|
typename F::result_type
|
apply_functor(F& f, tuple& bound_args, int_tuple,
|
apply_functor(F& f, tuple& bound_args, int_tuple,
|
const tuple& args)
|
const tuple& args)
|
{
|
{
|
return f(mu(get(bound_args), args)...);
|
return f(mu(get(bound_args), args)...);
|
}
|
}
|
|
|
template
|
template
|
class bound_functor
|
class bound_functor
|
{
|
{
|
typedef typename make_indexes::type indexes;
|
typedef typename make_indexes::type indexes;
|
|
|
public:
|
public:
|
typedef typename F::result_type result_type;
|
typedef typename F::result_type result_type;
|
|
|
explicit bound_functor(const F& f, const BoundArgs&... bound_args)
|
explicit bound_functor(const F& f, const BoundArgs&... bound_args)
|
: f(f), bound_args(bound_args...) { }
|
: f(f), bound_args(bound_args...) { }
|
|
|
template
|
template
|
typename F::result_type operator()(Args&... args) {
|
typename F::result_type operator()(Args&... args) {
|
return apply_functor(f, bound_args, indexes(), tie(args...));
|
return apply_functor(f, bound_args, indexes(), tie(args...));
|
}
|
}
|
|
|
private:
|
private:
|
F f;
|
F f;
|
tuple bound_args;
|
tuple bound_args;
|
};
|
};
|
|
|
template
|
template
|
struct is_bind_expression > {
|
struct is_bind_expression > {
|
static const bool value = true;
|
static const bool value = true;
|
};
|
};
|
|
|
template
|
template
|
inline bound_functor
|
inline bound_functor
|
bind(const F& f, const BoundArgs&... bound_args)
|
bind(const F& f, const BoundArgs&... bound_args)
|
{
|
{
|
return bound_functor(f, bound_args...);
|
return bound_functor(f, bound_args...);
|
}
|
}
|
|
|
|
|
// 3.6.4 Placeholders
|
// 3.6.4 Placeholders
|
template
|
template
|
struct is_placeholder > {
|
struct is_placeholder > {
|
static const int value = I;
|
static const int value = I;
|
};
|
};
|
|
|
placeholder<1> _1;
|
placeholder<1> _1;
|
placeholder<2> _2;
|
placeholder<2> _2;
|
placeholder<3> _3;
|
placeholder<3> _3;
|
placeholder<4> _4;
|
placeholder<4> _4;
|
placeholder<5> _5;
|
placeholder<5> _5;
|
placeholder<6> _6;
|
placeholder<6> _6;
|
placeholder<7> _7;
|
placeholder<7> _7;
|
placeholder<8> _8;
|
placeholder<8> _8;
|
placeholder<9> _9;
|
placeholder<9> _9;
|
|
|
// Test code
|
// Test code
|
template
|
template
|
struct plus {
|
struct plus {
|
typedef T result_type;
|
typedef T result_type;
|
|
|
T operator()(T x, T y) { return x + y; }
|
T operator()(T x, T y) { return x + y; }
|
};
|
};
|
|
|
template
|
template
|
struct multiplies {
|
struct multiplies {
|
typedef T result_type;
|
typedef T result_type;
|
|
|
T operator()(T x, T y) { return x * y; }
|
T operator()(T x, T y) { return x * y; }
|
};
|
};
|
|
|
template
|
template
|
struct negate {
|
struct negate {
|
typedef T result_type;
|
typedef T result_type;
|
|
|
T operator()(T x) { return -x; }
|
T operator()(T x) { return -x; }
|
};
|
};
|
|
|
int main()
|
int main()
|
{
|
{
|
int seventeen = 17;
|
int seventeen = 17;
|
int forty_two = 42;
|
int forty_two = 42;
|
|
|
assert(bind(plus(), _1, _2)(seventeen, forty_two) == 59);
|
assert(bind(plus(), _1, _2)(seventeen, forty_two) == 59);
|
assert(bind(plus(), _1, _1)(seventeen, forty_two) == 34);
|
assert(bind(plus(), _1, _1)(seventeen, forty_two) == 34);
|
assert(bind(plus(), _2, _1)(seventeen, forty_two) == 59);
|
assert(bind(plus(), _2, _1)(seventeen, forty_two) == 59);
|
assert(bind(plus(), 5, _1)(seventeen, forty_two) == 22);
|
assert(bind(plus(), 5, _1)(seventeen, forty_two) == 22);
|
assert(bind(plus(), ref(seventeen), _2)(seventeen, forty_two) == 59);
|
assert(bind(plus(), ref(seventeen), _2)(seventeen, forty_two) == 59);
|
assert(bind(plus(), bind(multiplies(), 3, _1), _2)(seventeen, forty_two)
|
assert(bind(plus(), bind(multiplies(), 3, _1), _2)(seventeen, forty_two)
|
== 93);
|
== 93);
|
return 0;
|
return 0;
|
}
|
}
|
|
|
