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<h1 align="center"><a href="../index.html">Boost.Python</a></h1>
<h2 align="center">Header <boost/python/enum.hpp></h2>
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<h2>Contents</h2>
<dl class="page-index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href="#classes">Classes</a></dt>
<dd>
<dl class="page-index">
<dt><a href="#enum_-spec">Class template
<code>enum_</code></a></dt>
<dd>
<dl class="page-index">
<dt><a href="#enum_-spec-synopsis">Class template <code>enum_</code>
synopsis</a></dt>
<dt><a href="#enum_-spec-ctors">Class template <code>enum_</code>
constructors</a></dt>
<dt><a href="#enum_-spec-modifiers">Class template <code>enum_</code>
modifier functions</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt><a href="#examples">Example(s)</a></dt>
</dl>
<hr>
<h2><a name="introduction"></a>Introduction</h2>
<p><code><boost/python/enum.hpp></code> defines the
interface through which users expose their C++ enumeration types
to Python. It declares the
<code>enum_</code> class template, which is parameterized on the
enumeration type being exposed. </p>
<h2><a name="classes"></a>Classes</h2>
<h3><a name="enum_-spec"></a>Class template
<code>enum_<T></code></h3>
<p>Creates a Python class derived from Python's <code>int</code>
type which is associated with the C++ type passed as its first
parameter.
<h4><a name="enum_-spec-synopsis"></a>Class template <code>enum_</code>
synopsis</h4>
<pre>
namespace boost { namespace python
{
template <class T>
class enum_ : public <a href="object.html#object-spec">object</a>
{
enum_(char const* name, char const* doc = 0);
enum_<T>& value(char const* name, T);
enum_<T>& export_values();
};
}}
</pre>
<h4><a name="enum_-spec-ctors"></a>Class template <code>enum_</code>
constructors</h4>
<pre>
enum_(char const* name, char const* doc=0);
</pre>
<dl class="function-semantics">
<dt><b>Requires:</b> <code>name</code> is an <a href=
"definitions.html#ntbs">ntbs</a> which conforms to Python's <a href=
"http://www.python.org/doc/current/ref/identifiers.html">identifier
naming rules</a>.
<dt><b>Effects:</b> Constructs an <code>enum_</code> object
holding a Python extension type derived from <code>int</code>
which is named <code>name</code>. The
<code>name</code>d attribute of the <a href=
"scope.html#introduction">current scope</a> is bound to the new
extension type.</dt>
</dl>
<h4><a name="enum_-spec-modifiers"></a>Class template
<code>enum_</code> modifier functions</h4>
<pre>
inline enum_<T>& value(char const* name, T x);
</pre>
<dl class="function-semantics">
<dt><b>Requires:</b> <code>name</code> is an <a href=
"definitions.html#ntbs">ntbs</a> which conforms to Python's <a
href=
"http://www.python.org/doc/current/ref/identifiers.html">identifier
naming rules</a>.
<dt><b>Effects:</b> adds an instance of the wrapped enumeration
type with value <code>x</code> to the type's dictionary as the
<code>name</code>d attribute.</dt>
<dt><b>Returns:</b> <code>*this</code></dt>
</dl>
<pre>
inline enum_<T>& export_values();
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> sets attributes in the current <a
href="scope.html#scope-spec"><code>scope</code></a> with the
same names and values as all enumeration values exposed so far
by calling <code>value()</code>.</dt>
<dt><b>Returns:</b> <code>*this</code></dt>
</dl>
<h2><a name="examples"></a>Example(s)</h2>
<p>C++ module definition
<pre>
#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_);
}
</pre>
<p>Interactive Python:
<pre>
>>> 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
</pre>
<hr>
Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
13 December, 2002
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
<p><i>© Copyright <a href=
"http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p>
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