108 lines
2.9 KiB
Plaintext
108 lines
2.9 KiB
Plaintext
[section boost/python/enum.hpp]
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[section Introduction]
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<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.
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[endsect]
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[section Class template `enum_`]
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Creates a Python class derived from Python's `int` type which is associated with the C++ type passed as its first parameter.
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``
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namespace boost { namespace python
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{
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template <class T>
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class enum_ : public object
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{
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enum_(char const* name, char const* doc = 0);
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enum_<T>& value(char const* name, T);
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enum_<T>& export_values();
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};
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}}
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``
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[endsect]
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[section Class template `enum_` constructors]
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``enum_(char const* name, char const* doc=0);``
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[variablelist
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[[Requires][name is an [link ntbs] which conforms to Python's [@http://www.python.org/doc/current/ref/identifiers.html identifier naming rules].]]
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[[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.]]
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]
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[endsect]
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[section Class template `enum_` modifier functions]
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``enum_<T>& value(char const* name, T x);``
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[variablelist
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[[Requires][name is an [link ntbs] which conforms to Python's [@http://www.python.org/doc/current/ref/identifiers.html identifier naming rules].]]
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[[Effects][adds an instance of the wrapped enumeration type with value x to the type's dictionary as the named attribute.]]
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[[Returns][`*this`]]
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]
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``enum_<T>& export_values();``
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[variablelist
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[[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().]]
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[[Returns][`*this`]]
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]
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[endsect]
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[section Example]
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C++ module definition
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``
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#include <boost/python/enum.hpp>
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#include <boost/python/def.hpp>
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#include <boost/python/module.hpp>
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using namespace boost::python;
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enum color { red = 1, green = 2, blue = 4 };
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color identity_(color x) { return x; }
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BOOST_PYTHON_MODULE(enums)
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{
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enum_<color>("color")
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.value("red", red)
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.value("green", green)
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.export_values()
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.value("blue", blue)
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;
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def("identity", identity_);
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}
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``
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Interactive Python:
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``
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>>> from enums import *
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>>> identity(red)
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enums.color.red
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>>> identity(color.red)
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enums.color.red
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>>> identity(green)
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enums.color.green
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>>> identity(color.green)
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enums.color.green
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>>> identity(blue)
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Traceback (most recent call last):
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File "<stdin>", line 1, in ?
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NameError: name 'blue' is not defined
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>>> identity(color.blue)
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enums.color.blue
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>>> identity(color(1))
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enums.color.red
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>>> identity(color(2))
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enums.color.green
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>>> identity(color(3))
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enums.color(3)
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>>> identity(color(4))
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enums.color.blue
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>>> identity(1)
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Traceback (most recent call last):
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File "<stdin>", line 1, in ?
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TypeError: bad argument type for built-in operation
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``
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[endsect]
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[endsect]
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