...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
self_ns::self_t
self_t
synopsisself_t
inplace operatorsself_t
comparison functionsself_t
non-member operationsself_t
unary operationsself_t
value operationsother
other
synopsisoperator_
operator_
synopsis<boost/python/operators.hpp>
provides types and
functions for automatically generating Python special methods
from the corresponding C++ constructs. Most of these constructs are
operator expressions, hence the name. To use the facility, substitute the
self
object for an object of the
class type being wrapped in the expression to be exposed, and pass the
result to class_<>::def(). Much of
what is exposed in this header should be considered part of the
implementation, so is not documented in detail here.
self_ns::self_t
self_ns::self_t
is the actual type of the self
object. The library isolates
self_t
in its own namespace, self_ns
, 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 self_t
directly.
self_ns::self_t
synopsisnamespace boost { namespace python { namespace self_ns { { unspecified-type-declaration self_t; // inplace operators template <class T> operator_<unspecified> operator+=(self_t, T); template <class T> operator_<unspecified> operator-=(self_t, T); template <class T> operator_<unspecified> operator*=(self_t, T); template <class T> operator_<unspecified> operator/=(self_t, T); template <class T> operator_<unspecified> operator%=(self_t, T); template <class T> operator_<unspecified> operator>>=(self_t, T); template <class T> operator_<unspecified> operator<<=(self_t, T); template <class T> operator_<unspecified> operator&=(self_t, T); template <class T> operator_<unspecified> operator^=(self_t, T); template <class T> operator_<unspecified> operator|=(self_t, T); // comparisons template <class L, class R> operator_<unspecified> operator==(L const&, R const&); template <class L, class R> operator_<unspecified> operator!=(L const&, R const&); template <class L, class R> operator_<unspecified> operator<(L const&, R const&); template <class L, class R> operator_<unspecified> operator>(L const&, R const&); template <class L, class R> operator_<unspecified> operator<=(L const&, R const&); template <class L, class R> operator_<unspecified> operator>=(L const&, R const&); // non-member operations template <class L, class R> operator_<unspecified> operator+(L const&, R const&); template <class L, class R> operator_<unspecified> operator-(L const&, R const&); template <class L, class R> operator_<unspecified> operator*(L const&, R const&); template <class L, class R> operator_<unspecified> operator/(L const&, R const&); template <class L, class R> operator_<unspecified> operator%(L const&, R const&); template <class L, class R> operator_<unspecified> operator>>(L const&, R const&); template <class L, class R> operator_<unspecified> operator<<(L const&, R const&); template <class L, class R> operator_<unspecified> operator&(L const&, R const&); template <class L, class R> operator_<unspecified> operator^(L const&, R const&); template <class L, class R> operator_<unspecified> operator|(L const&, R const&); template <class L, class R> operator_<unspecified> pow(L const&, R const&); // unary operations operator_<unspecified> operator-(self_t); operator_<unspecified> operator+(self_t); operator_<unspecified> operator~(self_t); operator_<unspecified> operator!(self_t); // value operations operator_<unspecified> int_(self_t); operator_<unspecified> long_(self_t); operator_<unspecified> float_(self_t); operator_<unspecified> complex_(self_t); operator_<unspecified> str(self_t); operator_<unspecified> repr(self_t); }}};The tables below describe the methods generated when the results of the expressions described are passed as arguments to class_<>::def().
x
is an object of the class type being wrapped.
self_t
inplace
operatorsr
is an object of type
other<T>
,
y
is an object of type T
; otherwise,
y
is an object of the same type as
r
.
C++ Expression | Python Method Name | C++ Implementation |
---|---|---|
self += r |
__iadd__ |
x += y |
self -= r |
__isub__ |
x -= y |
self *= r |
__imul__ |
x *= y |
self /= r |
__idiv__ |
x /= y |
self %= r |
__imod__ |
x %= y |
self >>= r |
__irshift__ |
x >>= y |
self <<= r |
__ilshift__ |
x <<= y |
self &= r |
__iand__ |
x &= y |
self ^= r |
__ixor__ |
x ^= y |
self |= r |
__ior__ |
x |= y |
self_t
comparison functionsr
is of type self_t
, y
is an object of
the same type as x
; l
or r
is an object of type
other<T>
,
y
is an object of type T
; y
is an object of the same type as
l
or r
.l
is never of type self_t
.
The column of Python Expressions illustrates the expressions
that will be supported in Python for objects convertible to the types of
x
and y
. The secondary operation arises due to
Python's reflection
rules for rich comparison operators, and are only used when the
corresponding operation is not defined as a method of the y
object.
C++ Expression | Python Method Name | C++ Implementation | Python Expressions (primary, secondary) |
---|---|---|---|
self == r |
__eq__ |
x == y |
x == y, y == x |
l == self |
__eq__ |
y == x |
y == x, x == y |
self != r |
__ne__ |
x != y |
x != y, y != x |
l != self |
__ne__ |
y != x |
y != x, x != y |
self < r |
__lt__ |
x < y |
x < y, y > x |
l < self |
__gt__ |
y < x |
y > x, x < y |
self > r |
__gt__ |
x > y |
x > y, y < x |
l > self |
__lt__ |
y > x |
y < x, x > y |
self <= r |
__le__ |
x <= y |
x <= y, y >= x |
l <= self |
__ge__ |
y <= x |
y >= x, x <= y |
self >= r |
__ge__ |
x >= y |
x >= y, y <= x |
l >= self |
__le__ |
y >= x |
y <= x, x >= y |
self_t
non-member
operations__r
" below will only
be called if the left-hand operand does not already support the given
operation, as described here.
C++ Expression | Python Method Name | C++ Implementation |
---|---|---|
self + r |
__add__ |
x + y |
l + self |
__radd__ |
y + x |
self - r |
__sub__ |
x - y |
l - self |
__rsub__ |
y - x |
self * r |
__mul__ |
x * y |
l * self |
__rmul__ |
y * x |
self / r |
__div__ |
x / y |
l / self |
__rdiv__ |
y / x |
self % r |
__mod__ |
x % y |
l % self |
__rmod__ |
y % x |
self >> r |
__rshift__ |
x >> y |
l >> self |
__rrshift__ |
y >> x |
self << r |
__lshift__ |
x << y |
l << self |
__rlshift__ |
y << x |
self & r |
__and__ |
x & y |
l & self |
__rand__ |
y & x |
self ^ r |
__xor__ |
x ^ y |
l ^ self |
__rxor__ |
y ^ x |
self | r |
__or__ |
x | y |
l | self |
__ror__ |
y | x |
pow(self, r) |
__pow__ |
pow(x, y) |
pow(l, self) |
__rpow__ |
pow(y, x) |
self_t
unary
operationsC++ Expression | Python Method Name | C++ Implementation |
---|---|---|
-self |
__neg__ |
-x |
+self |
__pos__ |
+x |
~self |
__invert__ |
~x |
not self or !self |
__nonzero__ |
!!x |
self_t
value
operationsC++ Expression | Python Method Name | C++ Implementation |
---|---|---|
int_(self) |
__int__ |
long(x) |
long_ |
__long__ |
PyLong_FromLong(x) |
float_ |
__float__ |
double(x) |
complex_ |
__complex__ |
std::complex<double>(x) |
str |
__str__ |
lexical_cast<std::string>(x) |
repr |
__repr__ |
lexical_cast<std::string>(x) |
other
Instances of other<T>
can be used in operator
expressions with self; the result is equivalent
to the same expression with a T
object in place of
other<T>
. Use other<T>
to prevent
construction of a T
object in case it is heavyweight, when
no constructor is available, or simply for clarity.
namespace boost { namespace python { template <class T> struct other { }; }}
detail::operator_
Instantiations of detail::operator_<>
are used as
the return type of operator expressions involving self
. This should be considered an implementation
detail and is only documented here as a way of showing how the result of
self
-expressions match calls to class_<>::def().
detail::operator_
synopsisnamespace boost { namespace python { namespace detail { template <unspecified> struct operator_ { }; }}}
namespace boost { namespace python { using self_ns::self; }}
#include <boost/python/module.hpp> #include <boost/python/class.hpp> #include <boost/python/operators.hpp> #include <boost/operators.hpp> struct number : boost::integer_arithmetic<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) ; }
Revised 5 October, 2004
© Copyright Dave Abrahams 2002.