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[section boost/python/stl_iterator.hpp]
[section Introduction]
<boost/python/stl_iterator.hpp> provides types for creating C++ Iterators from [@http://www.python.org/doc/current/lib/typeiter.html Python iterables].
[endsect]
[section Class template `stl_input_iterator`]
Instances of `stl_input_iterator<T>` hold a Python iterator and adapt it for use with STL algorithms. `stl_input_iterator<T>` satisfies the requirements for an Input Iterator.
[table
[[Template Parameter][Requirements][Semantics][Default]]
[[ValueType][ValueType must be CopyConstructible.][Dereferencing an instance of `stl_input_iterator<ValueType>` will return an rvalue of type ValueType.][None]]
]
``
namespace boost { namespace python
{
template <class ValueType>
struct stl_input_iterator
{
typedef std::ptrdiff_t difference_type;
typedef ValueType value_type;
typedef ValueType* pointer;
typedef ValueType reference;
typedef std::input_iterator_tag iterator_category;
stl_input_iterator();
stl_input_iterator(object const& ob);
stl_input_iterator& operator++();
stl_input_iterator operator++(int);
ValueType operator*() const;
friend bool operator==(stl_input_iterator const& lhs, stl_input_iterator const& rhs);
friend bool operator!=(stl_input_iterator const& lhs, stl_input_iterator const& rhs);
private:
object it; // For exposition only
object ob; // For exposition only
};
}}
``
[endsect]
[section Class template `stl_input_iterator` constructors]
``
stl_input_iterator()
``
[variablelist
[[Effects][Creates a past-the-end input iterator, useful for signifying the end of a sequence. ]]
[[Postconditions][`this` is past-the-end]]
[[Throws][Nothing.]]
]
``stl_input_iterator(object const& ob)``
[variablelist
[[Effects][Calls ob.attr("__iter__")() and stores the resulting Python iterator object in this->it. Then, calls this->it.attr("next")() and stores the result in this->ob. If the sequence is exhausted, sets this->ob to object(). ]]
[[Postconditions][this is a dereferenceable or past-the-end.]]
]
[endsect]
[section Class template `stl_input_iterator` modifiers]
``
stl_input_iterator &operator++()
``
[variablelist
[[Effects][Calls this->it.attr("next")() and stores the result in this->ob. If the sequence is exhausted, sets this->ob to object(). ]]
[[Postconditions][this is a dereferenceable or past-the-end.]]
[[Returns][`*this`]]
]
``stl_input_iterator &operator++(int)``
[variablelist
[[Effects][`stl_input_iterator tmp = *this; ++*this; return tmp;`]]
[[Postconditions][this is a dereferenceable or past-the-end.]]
]
[endsect]
[section Class template `stl_input_iterator` observers]
``
ValueType operator*() const
``
[variablelist
[[Effects][Returns the current element in the sequence. ]]
[[Returns][`extract<ValueType>(this->ob);`]]
]
``
friend bool operator==(stl_input_iterator const& lhs, stl_input_iterator const& rhs)
``
[variablelist
[[Effects][Returns true if both iterators are dereferenceable or if both iterators are past-the-end, false otherwise. ]]
[[Returns][`(lhs.ob == object()) == (rhs.ob == object())`]]
]
``
friend bool operator!=(stl_input_iterator const& lhs, stl_input_iterator const& rhs)
``
[variablelist
[[Effects][Returns false if both iterators are dereferenceable or if both iterators are past-the-end, true otherwise. ]]
[[Returns][`!(lhs == rhs)`]]
]
[endsect]
[section Example]
``
#include <boost/python/object.hpp>
#include <boost/python/stl_iterator.hpp>
#include <list>
using namespace boost::python;
std::list<int> sequence_to_int_list(object const& ob)
{
stl_input_iterator<int> begin(ob), end;
return std::list<int>(begin, end);
}
``
[endsect]
[endsect]
|
