[section boost/python/enum.hpp]

[section Introduction]

<boost/python/enum.hpp> defines the interface through which users expose their C++ enumeration types to Python. It declares the `enum_` class template, which is parameterized on the enumeration type being exposed.

[endsect]

[section Class template `enum_`]

Creates a Python class derived from Python's `int` type which is associated with the C++ type passed as its first parameter.

``

namespace boost { namespace python

{

template <class T>

class enum_ : public object

{

enum_(char const* name, char const* doc = 0);

enum_<T>& value(char const* name, T);

enum_<T>& export_values();

};

}}

``

[endsect]

[section Class template `enum_` constructors]

``enum_(char const* name, char const* doc=0);``

[variablelist

[[Requires][name is an [link ntbs] which conforms to Python's [@http://www.python.org/doc/current/ref/identifiers.html identifier naming rules].]]

[[Effects][Constructs an `enum_` object holding a Python extension type derived from `int` which is named `name`. The named attribute of the [link high_level_components.boost_python_scope_hpp current scope] is bound to the new extension type.]]

]

[endsect]

[section Class template `enum_` modifier functions]

``enum_<T>& value(char const* name, T x);``

[variablelist

[[Requires][name is an [link ntbs] which conforms to Python's [@http://www.python.org/doc/current/ref/identifiers.html identifier naming rules].]]

[[Effects][adds an instance of the wrapped enumeration type with value x to the type's dictionary as the named attribute.]]

[[Returns][`*this`]]

]

``enum_<T>& export_values();``

[variablelist

[[Effects][sets attributes in the [link high_level_components.boost_python_scope_hpp current scope] with the same names and values as all enumeration values exposed so far by calling value().]]

[[Returns][`*this`]]

]

[endsect]

[section Example]

C++ module definition

``

#include <boost/python/enum.hpp>

#include <boost/python/def.hpp>

#include <boost/python/module.hpp>

using namespace boost::python;

enum color { red = 1, green = 2, blue = 4 };

color identity_(color x) { return x; }

BOOST_PYTHON_MODULE(enums)

{

enum_<color>("color")

.value("red", red)

.value("green", green)

.export_values()

.value("blue", blue)

;

def("identity", identity_);

}

``

Interactive Python:

``

>>> from enums import *

>>> identity(red)

enums.color.red

>>> identity(color.red)

enums.color.red

>>> identity(green)

enums.color.green

>>> identity(color.green)

enums.color.green

>>> identity(blue)

Traceback (most recent call last):

File "<stdin>", line 1, in ?

NameError: name 'blue' is not defined

>>> identity(color.blue)

enums.color.blue

>>> identity(color(1))

enums.color.red

>>> identity(color(2))

enums.color.green

>>> identity(color(3))

enums.color(3)

>>> identity(color(4))

enums.color.blue

>>> identity(1)

Traceback (most recent call last):

File "<stdin>", line 1, in ?

TypeError: bad argument type for built-in operation

``

[endsect]

[endsect]