mirror of
https://github.com/boostorg/iterator.git
synced 2025-07-29 04:17:32 +02:00
simplified named parameters mechanism
[SVN r10455]
This commit is contained in:
Jeremy Siek
@ -11,7 +11,9 @@
|
||||
// to its suitability for any purpose.
|
||||
//
|
||||
// Revision History:
|
||||
|
||||
//
|
||||
// 27 June 2001 Jeremy Siek
|
||||
// Simplified named template parameters.
|
||||
// 08 Mar 2001 Jeremy Siek
|
||||
// Added support for optional named template parameters.
|
||||
// 19 Feb 2001 David Abrahams
|
||||
@ -440,105 +442,155 @@ namespace detail {
|
||||
// Specify the defaults for iterator_adaptor's template parameters
|
||||
|
||||
struct default_value_type {
|
||||
template <class Base, class Traits>
|
||||
struct bind {
|
||||
template <class Info>
|
||||
class bind {
|
||||
typedef typename Info::base_type Base;
|
||||
public:
|
||||
typedef typename boost::detail::iterator_traits<Base>::value_type type;
|
||||
};
|
||||
};
|
||||
struct default_difference_type {
|
||||
template <class Base, class Traits>
|
||||
struct bind {
|
||||
template <class Info>
|
||||
class bind {
|
||||
typedef typename Info::base_type Base;
|
||||
public:
|
||||
typedef typename boost::detail::iterator_traits<Base>::difference_type type;
|
||||
};
|
||||
};
|
||||
struct default_iterator_category {
|
||||
template <class Base, class Traits>
|
||||
struct bind {
|
||||
template <class Info>
|
||||
class bind {
|
||||
typedef typename Info::base_type Base;
|
||||
public:
|
||||
typedef typename boost::detail::iterator_traits<Base>::iterator_category type;
|
||||
};
|
||||
};
|
||||
struct default_pointer {
|
||||
template <class Base, class Traits>
|
||||
struct bind {
|
||||
template <class Info>
|
||||
class bind {
|
||||
typedef typename Info::base_type Base;
|
||||
typedef typename Info::traits_type Traits;
|
||||
public:
|
||||
typedef typename Traits::value_type Value;
|
||||
typedef typename boost::detail::iterator_defaults<Base,Value>::pointer
|
||||
type;
|
||||
};
|
||||
};
|
||||
struct default_reference {
|
||||
template <class Base, class Traits>
|
||||
struct bind {
|
||||
template <class Info>
|
||||
class bind {
|
||||
typedef typename Info::base_type Base;
|
||||
typedef typename Info::traits_type Traits;
|
||||
public:
|
||||
typedef typename Traits::value_type Value;
|
||||
typedef typename boost::detail::iterator_defaults<Base,Value>::reference
|
||||
type;
|
||||
};
|
||||
};
|
||||
|
||||
#ifdef BOOST_MSVC
|
||||
// Using the default generator such as default_value_type
|
||||
// directly inside of resolve_default causes problems, but
|
||||
// going through this default_generator solves the problem
|
||||
// on MSVC.
|
||||
template <> struct default_generator<default_value_type> {
|
||||
typedef default_value_type type; };
|
||||
template <> struct default_generator<default_difference_type> {
|
||||
typedef default_difference_type type; };
|
||||
template <> struct default_generator<default_pointer> {
|
||||
typedef default_pointer type; };
|
||||
template <> struct default_generator<default_reference> {
|
||||
typedef default_reference type; };
|
||||
template <> struct default_generator<default_iterator_category> {
|
||||
typedef default_iterator_category type; };
|
||||
#endif
|
||||
|
||||
//===========================================================================
|
||||
// Support for named template parameters
|
||||
|
||||
#if !defined(__BORLANDC__)
|
||||
// Borland C++ thinks the nested recursive inheritance here is illegal.
|
||||
struct value_type_tag { };
|
||||
struct reference_tag { };
|
||||
struct pointer_tag { };
|
||||
struct iterator_category_tag { };
|
||||
struct difference_type_tag { };
|
||||
|
||||
template <class V = default_argument,
|
||||
class R = default_argument,
|
||||
class P = default_argument,
|
||||
class C = default_argument,
|
||||
class D = default_argument>
|
||||
struct iter_traits_gen : public named_template_param_base {
|
||||
template <class T>
|
||||
struct value_type : public iter_traits_gen<T,R,P,C,D> { };
|
||||
template <class T>
|
||||
struct reference : public iter_traits_gen<V,T,P,C,D> { };
|
||||
template <class T>
|
||||
struct pointer : public iter_traits_gen<V,R,T,C,D> { };
|
||||
template <class T>
|
||||
struct iterator_category : public iter_traits_gen<V,R,P,T,D>{};
|
||||
template <class T>
|
||||
struct difference_type : public iter_traits_gen<V,R,P,C,T> { };
|
||||
|
||||
typedef boost::iterator<C, V, D, P, R> traits;
|
||||
};
|
||||
#endif
|
||||
|
||||
BOOST_NAMED_TEMPLATE_PARAM(value_type);
|
||||
BOOST_NAMED_TEMPLATE_PARAM(reference);
|
||||
BOOST_NAMED_TEMPLATE_PARAM(pointer);
|
||||
BOOST_NAMED_TEMPLATE_PARAM(iterator_category);
|
||||
BOOST_NAMED_TEMPLATE_PARAM(difference_type);
|
||||
|
||||
template <class Base, class Value, class Reference, class Pointer,
|
||||
class Category, class Distance>
|
||||
class iterator_adaptor_traits_gen
|
||||
template <class Base, class Value, class Reference, class Pointer, class Category, class Distance>
|
||||
class iter_adaptor_traits_gen
|
||||
{
|
||||
typedef boost::iterator<Category, Value, Distance, Pointer, Reference>
|
||||
Traits0;
|
||||
typedef std::pair<typename wrap_param<Value, value_type_tag>::type,
|
||||
std::pair<typename wrap_param<Reference, reference_tag>::type,
|
||||
std::pair<typename wrap_param<Pointer, pointer_tag>::type,
|
||||
std::pair<typename wrap_param<Category, iterator_category_tag>::type,
|
||||
std::pair<typename wrap_param<Distance, difference_type_tag>::type,
|
||||
list_end_type> > > > > NamedParamList;
|
||||
|
||||
typedef typename get_value_type<Base,
|
||||
typename boost::remove_const<Value>::type, Traits0
|
||||
>::type value_type;
|
||||
typedef typename get_difference_type<Base, Distance, Traits0>::type
|
||||
difference_type;
|
||||
typedef typename get_iterator_category<Base, Category, Traits0>::type
|
||||
iterator_category;
|
||||
// Figure out the value_type
|
||||
typedef typename find_param<NamedParamList, value_type_tag>::type Val;
|
||||
struct default_info {
|
||||
typedef Base base_type;
|
||||
typedef void traits_type;
|
||||
};
|
||||
typedef typename resolve_default<Val, default_value_type, default_info>::type value_type;
|
||||
|
||||
typedef boost::iterator<iterator_category, value_type, difference_type,
|
||||
Pointer, Reference> Traits1;
|
||||
|
||||
typedef typename get_pointer<Base, Pointer, Traits1>::type pointer;
|
||||
typedef typename get_reference<Base, Reference, Traits1>::type reference;
|
||||
// Compute the difference_type
|
||||
typedef typename find_param<NamedParamList, difference_type_tag>::type
|
||||
Diff;
|
||||
typedef typename resolve_default<Diff, default_difference_type,
|
||||
default_info>::type difference_type;
|
||||
|
||||
// Determine the iterator_category
|
||||
typedef typename find_param<NamedParamList, iterator_category_tag>::type
|
||||
Cat;
|
||||
typedef typename resolve_default<Cat, default_iterator_category,
|
||||
default_info>::type iterator_category;
|
||||
|
||||
typedef boost::iterator<iterator_category, value_type, difference_type>
|
||||
Traits;
|
||||
struct default_info2 {
|
||||
typedef Base base_type;
|
||||
typedef Traits traits_type;
|
||||
};
|
||||
|
||||
// Extract the pointer type
|
||||
typedef typename find_param<NamedParamList, pointer_tag>::type Ptr;
|
||||
typedef typename resolve_default<Ptr, default_pointer, default_info2>::type
|
||||
pointer;
|
||||
|
||||
// Calculate the reference type
|
||||
typedef typename find_param<NamedParamList, reference_tag>::type Ref;
|
||||
typedef typename resolve_default<Ref, default_reference,
|
||||
default_info2>::type reference;
|
||||
public:
|
||||
typedef boost::iterator<iterator_category, value_type, difference_type,
|
||||
pointer, reference> type;
|
||||
};
|
||||
|
||||
} // namespace detail
|
||||
|
||||
|
||||
#if !defined(__BORLANDC__)
|
||||
struct iterator_traits_generator
|
||||
: public detail::iter_traits_gen<> { };
|
||||
#endif
|
||||
struct default_argument : public named_template_param_base {
|
||||
typedef void type;
|
||||
typedef void tag;
|
||||
};
|
||||
template <class T> struct value_type_is : public named_template_param_base {
|
||||
typedef T type;
|
||||
typedef detail::value_type_tag tag;
|
||||
};
|
||||
template <class T> struct reference_is : public named_template_param_base {
|
||||
typedef T type;
|
||||
typedef detail::reference_tag tag;
|
||||
};
|
||||
template <class T> struct pointer_is : public named_template_param_base {
|
||||
typedef T type;
|
||||
typedef detail::pointer_tag tag;
|
||||
};
|
||||
template <class T> struct iterator_category_is : public named_template_param_base {
|
||||
typedef T type;
|
||||
typedef detail::iterator_category_tag tag;
|
||||
};
|
||||
template <class T> struct difference_type_is : public named_template_param_base
|
||||
{
|
||||
typedef T type;
|
||||
typedef detail::difference_type_tag tag;
|
||||
};
|
||||
|
||||
// This macro definition is only temporary in this file
|
||||
# if !defined(BOOST_MSVC)
|
||||
@ -578,26 +630,25 @@ template <class T> struct undefined;
|
||||
// Distance - the difference_type of the resulting iterator. If not
|
||||
// supplied, iterator_traits<Base>::difference_type is used.
|
||||
template <class Base, class Policies,
|
||||
class Value = detail::default_argument,
|
||||
class Reference = BOOST_ARG_DEPENDENT_TYPENAME detail::choose_default_argument<Value>::type,
|
||||
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME detail::choose_default_argument<Reference>::type,
|
||||
class Category = BOOST_ARG_DEPENDENT_TYPENAME detail::choose_default_argument<Pointer>::type,
|
||||
class Distance = BOOST_ARG_DEPENDENT_TYPENAME detail::choose_default_argument<Category>::type
|
||||
class Value = default_argument,
|
||||
class Reference = default_argument,
|
||||
class Pointer = default_argument,
|
||||
class Category = default_argument,
|
||||
class Distance = default_argument
|
||||
>
|
||||
struct iterator_adaptor :
|
||||
#ifdef BOOST_RELOPS_AMBIGUITY_BUG
|
||||
iterator_comparisons<
|
||||
iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance>,
|
||||
typename detail::iterator_adaptor_traits_gen<Base,Value,Reference,Pointer,Category, Distance>::type
|
||||
typename detail::iter_adaptor_traits_gen<Base,Value,Reference,Pointer,Category, Distance>::type
|
||||
>
|
||||
#else
|
||||
detail::iterator_adaptor_traits_gen<Base,Value,Reference,Pointer,Category,Distance>::type
|
||||
detail::iter_adaptor_traits_gen<Base,Value,Reference,Pointer,Category, Distance>::type
|
||||
#endif
|
||||
{
|
||||
typedef iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance> self;
|
||||
typedef typename detail::iter_adaptor_traits_gen<Base,Value,Reference,Pointer,Category, Distance>::type Traits;
|
||||
public:
|
||||
typedef typename detail::iterator_adaptor_traits_gen<Base,Value,Reference,Pointer,Category,Distance>::type Traits;
|
||||
|
||||
typedef typename Traits::difference_type difference_type;
|
||||
typedef typename Traits::value_type value_type;
|
||||
typedef typename Traits::pointer pointer;
|
||||
@ -1139,7 +1190,7 @@ namespace detail {
|
||||
>::type type;
|
||||
# endif
|
||||
};
|
||||
}
|
||||
} // namespace detail
|
||||
|
||||
template <class Predicate, class Iterator,
|
||||
class Value = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::value_type,
|
||||
|
||||
Reference in New Issue
Block a user