<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
<!-- Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
<html>
<head>
<meta name="generator" content=
"HTML Tidy for Windows (vers 1st August 2002), see www.w3.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel="stylesheet" type="text/css" href="../boost.css">
<title>Boost.Python - <boost/python/operators.hpp></title>
</head>
<body>
<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
"header">
<tr>
<td valign="top" width="300">
<h3><a href="../../../../index.htm"><img height="86" width="277"
alt="C++ Boost" src="../../../../boost.png" border="0"></a></h3>
</td>
<td valign="top">
<h1 align="center"><a href="../index.html">Boost.Python</a></h1>
<h2 align="center">Header <boost/python/operators.hpp></h2>
</td>
</tr>
</table>
<hr>
<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="#self_t-spec">Class
<code>self_ns::self_t</code></a></dt>
<dd>
<dl class="page-index">
<dt><a href="#self_t-spec-synopsis">Class <code>self_t</code>
synopsis</a></dt>
<dt><a href="#self_t-spec-inplace">Class <code>self_t</code>
inplace operators</a></dt>
<dt><a href="#self_t-spec-comparisons">Class
<code>self_t</code> comparison functions</a></dt>
<dt><a href="#self_t-spec-ops">Class <code>self_t</code>
non-member operations</a></dt>
<dt><a href="#self_t-spec-value-unary-ops">Class
<code>self_t</code> unary operations</a></dt>
<dt><a href="#self_t-spec-value-ops">Class
<code>self_t</code> value operations</a></dt>
</dl>
</dd>
<dt><a href="#other-spec">Class template
<code>other</code></a></dt>
<dd>
<dl class="page-index">
<dt><a href="#other-spec-synopsis">Class <code>other</code>
synopsis</a></dt>
</dl>
</dd>
<dt><a href="#operator_-spec">Class template
<code>operator_</code></a></dt>
<dd>
<dl class="page-index">
<dt><a href="#operator_-spec-synopsis">Class
<code>operator_</code> synopsis</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt><a href="#objects">Objects</a></dt>
<dd>
<dl class="page-index">
<dt><a href="#self-spec">self</a></dt>
</dl>
</dd>
<dt><a href="#examples">Examples</a></dt>
</dl>
<hr>
<h2><a name="introduction"></a>Introduction</h2>
<p><code><boost/python/operators.hpp></code> provides types and
functions for automatically generating Python <a href=
"http://www.python.org/doc/ref/specialnames.html">special methods</a>
from the corresponding C++ constructs. Most of these constructs are
operator expressions, hence the name. To use the facility, substitute the
<code><a href="#self-spec">self</a></code> object for an object of the
class type being wrapped in the expression to be exposed, and pass the
result to <a href=
"class.html#class_-spec-modifiers">class_<>::def()</a>. Much of
what is exposed in this header should be considered part of the
implementation, so is not documented in detail here.</p>
<h2><a name="classes"></a>Classes</h2>
<h3><a name="self_t-spec"></a>Class <code>self_ns::self_t</code></h3>
<p><code>self_ns::self_t</code> is the actual type of the <a href=
"#self-spec"><code>self</code></a> object. The library isolates
<code>self_t</code> in its own namespace, <code>self_ns</code>, in order
to prevent the generalized operator templates which operate on it from
being found by argument-dependent lookup in other contexts. This should
be considered an implementation detail, since users should never have to
mention <code>self_t</code> directly.</p>
<h4><a name="self_t-spec-synopsis"></a>Class <code>self_ns::self_t</code>
synopsis</h4>
<pre>
namespace boost { namespace python { namespace self_ns {
{
<i>unspecified-type-declaration</i> self_t;
// inplace operators
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator+=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator-=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator*=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator/=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator%=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator>>=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator<<=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator&=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator^=(self_t, T);
template <class T> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator|=(self_t, T);
// comparisons
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator==(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator!=(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator<(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator>(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator<=(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator>=(L const&, R const&);
// non-member operations
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator+(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator-(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator*(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator/(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator%(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator>>(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator<<(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator&(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator^(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator|(L const&, R const&);
template <class L, class R> <a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> pow(L const&, R const&);
// unary operations
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator-(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator+(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator~(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> operator!(self_t);
// value operations
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> int_(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> long_(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> float_(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> complex_(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> str(self_t);
<a href=
"#operator_-spec">operator_</a><<i>unspecified</i>> repr(self_t);
}}};
</pre>
The tables below describe the methods generated when the results of the
expressions described are passed as arguments to <a href=
"class.html#class_-spec-modifiers">class_<>::def()</a>.
<code><b>x</b></code> is an object of the class type being wrapped.
<h4><a name="self_t-spec-inplace"></a>Class <code>self_t</code> inplace
operators</h4>
In the table below, If <code><b>r</b></code> is an object of type
<code><a href="#other-spec">other</a><T></code>,
<code><b>y</b></code> is an object of type <code>T</code>; otherwise,
<code><b>y</b></code> is an object of the same type as
<code><b>r</b></code>.
<table border="1" summary="self_t inplace operators">
<tr>
<th>C++ Expression</th>
<th>Python Method Name</th>
<th>C++ Implementation</th>
</tr>
<tr>
<td><code>self += r</code></td>
<td><code>__iadd__</code></td>
<td><code>x += y</code></td>
</tr>
<tr>
<td><code>self -= r</code></td>
<td><code>__isub__</code></td>
<td><code>x -= y</code></td>
</tr>
<tr>
<td><code>self *= r</code></td>
<td><code>__imul__</code></td>
<td><code>x *= y</code></td>
</tr>
<tr>
<td><code>self /= r</code></td>
<td><code>__idiv__</code></td>
<td><code>x /= y</code></td>
</tr>
<tr>
<td><code>self %= r</code></td>
<td><code>__imod__</code></td>
<td><code>x %= y</code></td>
</tr>
<tr>
<td><code>self >>= r</code></td>
<td><code>__irshift__</code></td>
<td><code>x >>= y</code></td>
</tr>
<tr>
<td><code>self <<= r</code></td>
<td><code>__ilshift__</code></td>
<td><code>x <<= y</code></td>
</tr>
<tr>
<td><code>self &= r</code></td>
<td><code>__iand__</code></td>
<td><code>x &= y</code></td>
</tr>
<tr>
<td><code>self ^= r</code></td>
<td><code>__ixor__</code></td>
<td><code>x ^= y</code></td>
</tr>
<tr>
<td><code>self |= r</code></td>
<td><code>__ior__</code></td>
<td><code>x |= y</code></td>
</tr>
</table>
<h4><a name="self_t-spec-comparisons"></a>Class <code>self_t</code>
comparison functions</h4>
In the tables below, if <code><b>r</b></code> is of type <code><a href=
"#self_t-spec">self_t</a></code>, <code><b>y</b></code> is an object of
the same type as <code>x</code>; <br>
if <code><b>l</b></code> or <code><b>r</b></code> is an object of type
<code><a href="#other-spec">other</a><T></code>,
<code><b>y</b></code> is an object of type <code>T</code>; <br>
otherwise, <code><b>y</b></code> is an object of the same type as
<code><b>l</b></code> or <code><b>r</b></code>.<br>
<code><b>l</b></code> is never of type <code><a href=
"#self_t-spec">self_t</a></code>.
<p>The column of <b>Python Expressions</b> illustrates the expressions
that will be supported in Python for objects convertible to the types of
<code>x</code> and <code>y</code>. The secondary operation arises due to
Python's <a href=
"http://www.python.org/doc/ref/customization.html#l2h-89">reflection
rules</a> for rich comparison operators, and are only used when the
corresponding operation is not defined as a method of the <code>y</code>
object.</p>
<table border="1" summary="self_t comparison functions">
<tr>
<th>C++ Expression</th>
<th>Python Method Name</th>
<th>C++ Implementation</th>
<th>Python Expressions<br>
(primary, secondary)</th>
</tr>
<tr>
<td><code>self == r</code></td>
<td><code>__eq__</code></td>
<td><code>x == y</code></td>
<td><code>x == y, y == x</code></td>
</tr>
<tr>
<td><code>l == self</code></td>
<td><code>__eq__</code></td>
<td><code>y == x</code></td>
<td><code>y == x, x == y</code></td>
</tr>
<tr>
<td><code>self != r</code></td>
<td><code>__ne__</code></td>
<td><code>x != y</code></td>
<td><code>x != y, y != x</code></td>
</tr>
<tr>
<td><code>l != self</code></td>
<td><code>__ne__</code></td>
<td><code>y != x</code></td>
<td><code>y != x, x != y</code></td>
</tr>
<tr>
<td><code>self < r</code></td>
<td><code>__lt__</code></td>
<td><code>x < y</code></td>
<td><code>x < y, y > x</code></td>
</tr>
<tr>
<td><code>l < self</code></td>
<td><code>__gt__</code></td>
<td><code>y < x</code></td>
<td><code>y > x, x < y</code></td>
</tr>
<tr>
<td><code>self > r</code></td>
<td><code>__gt__</code></td>
<td><code>x > y</code></td>
<td><code>x > y, y < x</code></td>
</tr>
<tr>
<td><code>l > self</code></td>
<td><code>__lt__</code></td>
<td><code>y > x</code></td>
<td><code>y < x, x > y</code></td>
</tr>
<tr>
<td><code>self <= r</code></td>
<td><code>__le__</code></td>
<td><code>x <= y</code></td>
<td><code>x <= y, y >= x</code></td>
</tr>
<tr>
<td><code>l <= self</code></td>
<td><code>__ge__</code></td>
<td><code>y <= x</code></td>
<td><code>y >= x, x <= y</code></td>
</tr>
<tr>
<td><code>self >= r</code></td>
<td><code>__ge__</code></td>
<td><code>x >= y</code></td>
<td><code>x >= y, y <= x</code></td>
</tr>
<tr>
<td><code>l >= self</code></td>
<td><code>__le__</code></td>
<td><code>y >= x</code></td>
<td><code>y <= x, x >= y</code></td>
</tr>
</table>
<h4><a name="self_t-spec-ops"></a>Class <code>self_t</code> non-member
operations</h4>
The operations whose names begin with "<code>__r</code>" below will only
be called if the left-hand operand does not already support the given
operation, as described <a href=
"http://www.python.org/doc/current/ref/numeric-types.html#l2h-152">here</a>.
<table border="1" summary="self_t non-member operations">
<tr>
<th>C++ Expression</th>
<th>Python Method Name</th>
<th>C++ Implementation</th>
</tr>
<tr>
<td><code>self + r</code></td>
<td><code>__add__</code></td>
<td><code>x + y</code></td>
</tr>
<tr>
<td><code>l + self</code></td>
<td><code>__radd__</code></td>
<td><code>y + x</code></td>
</tr>
<tr>
<td><code>self - r</code></td>
<td><code>__sub__</code></td>
<td><code>x - y</code></td>
</tr>
<tr>
<td><code>l - self</code></td>
<td><code>__rsub__</code></td>
<td><code>y - x</code></td>
</tr>
<tr>
<td><code>self * r</code></td>
<td><code>__mul__</code></td>
<td><code>x * y</code></td>
</tr>
<tr>
<td><code>l * self</code></td>
<td><code>__rmul__</code></td>
<td><code>y * x</code></td>
</tr>
<tr>
<td><code>self / r</code></td>
<td><code>__div__</code></td>
<td><code>x / y</code></td>
</tr>
<tr>
<td><code>l / self</code></td>
<td><code>__rdiv__</code></td>
<td><code>y / x</code></td>
</tr>
<tr>
<td><code>self % r</code></td>
<td><code>__mod__</code></td>
<td><code>x % y</code></td>
</tr>
<tr>
<td><code>l % self</code></td>
<td><code>__rmod__</code></td>
<td><code>y % x</code></td>
</tr>
<tr>
<td><code>self >> r</code></td>
<td><code>__rshift__</code></td>
<td><code>x >> y</code></td>
</tr>
<tr>
<td><code>l >> self</code></td>
<td><code>__rrshift__</code></td>
<td><code>y >> x</code></td>
</tr>
<tr>
<td><code>self << r</code></td>
<td><code>__lshift__</code></td>
<td><code>x << y</code></td>
</tr>
<tr>
<td><code>l << self</code></td>
<td><code>__rlshift__</code></td>
<td><code>y << x</code></td>
</tr>
<tr>
<td><code>self & r</code></td>
<td><code>__and__</code></td>
<td><code>x & y</code></td>
</tr>
<tr>
<td><code>l & self</code></td>
<td><code>__rand__</code></td>
<td><code>y & x</code></td>
</tr>
<tr>
<td><code>self ^ r</code></td>
<td><code>__xor__</code></td>
<td><code>x ^ y</code></td>
</tr>
<tr>
<td><code>l ^ self</code></td>
<td><code>__rxor__</code></td>
<td><code>y ^ x</code></td>
</tr>
<tr>
<td><code>self | r</code></td>
<td><code>__or__</code></td>
<td><code>x | y</code></td>
</tr>
<tr>
<td><code>l | self</code></td>
<td><code>__ror__</code></td>
<td><code>y | x</code></td>
</tr>
<tr>
<td><code>pow(self, r)</code></td>
<td><code>__pow__</code></td>
<td><code>pow(x, y)</code></td>
</tr>
<tr>
<td><code>pow(l, self)</code></td>
<td><code>__rpow__</code></td>
<td><code>pow(y, x)</code></td>
</tr>
</table>
<h4><a name="self_t-spec-value-unary-ops"></a>Class <code>self_t</code> unary
operations</h4>
<table border="1" summary="self_t unary operations">
<tr>
<th>C++ Expression</th>
<th>Python Method Name</th>
<th>C++ Implementation</th>
</tr>
<tr>
<td><code>-self</code></td>
<td><code>__neg__</code></td>
<td><code>-x</code></td>
</tr>
<tr>
<td><code>+self</code></td>
<td><code>__pos__</code></td>
<td><code>+x</code></td>
</tr>
<tr>
<td><code>~self</code></td>
<td><code>__invert__</code></td>
<td><code>~x</code></td>
</tr>
<tr>
<td><code>not self</code><br><i>or</i><br><code>!self</code></td>
<td><code>__nonzero__</code></td>
<td><code>!!x</code></td>
</tr>
</table>
<h4><a name="self_t-spec-value-ops"></a>Class <code>self_t</code> value
operations</h4>
<table border="1" summary="self_t value operations">
<tr>
<th>C++ Expression</th>
<th>Python Method Name</th>
<th>C++ Implementation</th>
</tr>
<tr>
<td><code>int_(self)</code></td>
<td><code>__int__</code></td>
<td><code>long(x)</code></td>
</tr>
<tr>
<td><code>long_</code></td>
<td><code>__long__</code></td>
<td><code>PyLong_FromLong(x)</code></td>
</tr>
<tr>
<td><code>float_</code></td>
<td><code>__float__</code></td>
<td><code>double(x)</code></td>
</tr>
<tr>
<td><code>complex_</code></td>
<td><code>__complex__</code></td>
<td><code>std::complex<double>(x)</code></td>
</tr>
<tr>
<td><code>str</code></td>
<td><code>__str__</code></td>
<td><code><a href=
"../../../conversion/lexical_cast.htm#lexical_cast">lexical_cast</a><std::string>(x)</code></td>
</tr>
<tr>
<td><code>repr</code></td>
<td><code>__repr__</code></td>
<td><code><a href=
"../../../conversion/lexical_cast.htm#lexical_cast">lexical_cast</a><std::string>(x)</code></td>
</tr>
</table>
<h3><a name="other-spec"></a>Class Template <code>other</code></h3>
<p>Instances of <code>other<T></code> can be used in operator
expressions with <a href="#self-spec">self</a>; the result is equivalent
to the same expression with a <code>T</code> object in place of
<code>other<T></code>. Use <code>other<T></code> to prevent
construction of a <code>T</code> object in case it is heavyweight, when
no constructor is available, or simply for clarity.</p>
<h4><a name="other-spec-synopsis"></a>Class Template other synopsis</h4>
<pre>
namespace boost { namespace python
{
template <class T>
struct other
{
};
}}
</pre>
<!-- -->
<h3><a name="operator_-spec"></a>Class Template
<code>detail::operator_</code></h3>
<p>Instantiations of <code>detail::operator_<></code> are used as
the return type of operator expressions involving <code><a href=
"#self-spec">self</a></code>. This should be considered an implementation
detail and is only documented here as a way of showing how the result of
<code>self</code>-expressions match calls to <a href=
"class.html#class_-spec-modifiers">class_<>::def()</a>.</p>
<h4><a name="operator_-spec-synopsis"></a>Class Template
<code>detail::operator_</code> synopsis</h4>
<pre>
namespace boost { namespace python { namespace detail
{
template <<i>unspecified</i>>
struct operator_
{
};
}}}
</pre>
<h2><a name="objects"></a>Objects</h2>
<p><a name="self-spec"><code>self</code></a></p>
<pre>
namespace boost { namespace python
{
using self_ns::self;
}}
</pre>
<h2><a name="examples"></a>Example</h2>
<pre>
#include <boost/python/module.hpp>
#include <boost/python/class.hpp>
#include <boost/python/operators.hpp>
#include <boost/operators.hpp>
struct number
: boost::<a href=
"../../../utility/operators.htm#grpd_oprs">integer_arithmetic</a><number>
{
explicit number(long x_) : x(x_) {}
operator long() const { return x; }
template <class T>
number& operator+=(T const& rhs)
{ x += rhs; return *this; }
template <class T>
number& operator-=(T const& rhs)
{ x -= rhs; return *this; }
template <class T>
number& operator*=(T const& rhs)
{ x *= rhs; return *this; }
template <class T>
number& operator/=(T const& rhs)
{ x /= rhs; return *this; }
template <class T>
number& operator%=(T const& rhs)
{ x %= rhs; return *this; }
long x;
};
using namespace boost::python;
BOOST_PYTHON_MODULE(demo)
{
class_<number>("number", init<long>())
// interoperate with self
.def(self += self)
.def(self + self)
.def(self -= self)
.def(self - self)
.def(self *= self)
.def(self * self)
.def(self /= self)
.def(self / self)
.def(self %= self)
.def(self % self)
// Convert to Python int
.def(int_(self))
// interoperate with long
.def(self += long())
.def(self + long())
.def(long() + self)
.def(self -= long())
.def(self - long())
.def(long() - self)
.def(self *= long())
.def(self * long())
.def(long() * self)
.def(self /= long())
.def(self / long())
.def(long() / self)
.def(self %= long())
.def(self % long())
.def(long() % self)
;
}
</pre>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
5 October, 2004
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>© Copyright <a href=
"http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p>
</body>
</html>
