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[section boost/python/overloads.hpp]
[section Introduction]
Defines facilities for generating families of overloaded Python functions and extension class methods from C++ functions and member functions with default arguments, or from similar families of C++ overloads
[section overload-dispatch-expressions]
An overload-dispatch-expression is used to describe a family of overloaded methods to be generated for an extension class. It has the following properties:
[variablelist
[[docstring][An [link ntbs] whose value will bound to the methods' `__doc__` attribute]]
[[keywords][A [link function_invocation_and_creation.boost_python_args_hpp.introduction.keyword_expressions keyword-expression] which will be used to name (a trailing subsequence of) the arguments to the generated methods.]]
[[call policies][An instance of some type which models CallPolicies.]]
[[minimum arity][The minimum number of arguments to be accepted by a generated method overload.]]
[[maximum arity][The maximum number of arguments to be accepted by a generated method overload.]]
]
[endsect]
[endsect]
[section OverloadDispatcher Concept]
An OverloadDispatcher X is a class which has a minimum arity and a maximum arity, and for which the following following are valid overload-dispatch-expressions, with the same minimum and maximum arity as the OverloadDispatcher.
``
X()
X(docstring)
X(docstring, keywords)
X(keywords, docstring)
X()[policies]
X(docstring)[policies]
X(docstring, keywords)[policies]
X(keywords, docstring)[policies]
``
* If policies are supplied, it must be an instance of a type which models [link concepts.callpolicies CallPolicies], and will be used as the result's call policies. Otherwise the result's call policies will be an instance of [link function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici `default_call_policies`].
* If docstring is supplied it must be an [link ntbs], and will be used as the result's docstring. Otherwise the result has an empty docstring.
* If keywords is supplied it must be the result of a [link function_invocation_and_creation.boost_python_args_hpp.introduction.keyword_expressions keyword-expression] whose length is no greater than X's maximum arity, and will be used as the result's keywords. Otherwise the result's keywords will be empty.
[endsect]
[section Macros]
``
BOOST_PYTHON_FUNCTION_OVERLOADS(name, func_id, min_args, max_args)
``
Expands to the definition of an OverloadDispatcher called name in the current scope which can be used to generate the following function invocation:
``func_id(a1, a2,...ai);``
for all `min_args <= i <= max_args`.
``
BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(name, member_name, min_args, max_args)
``
Expands to the definition of an OverloadDispatcher called name in the current scope which can be used to generate the following function invocation:
``x.member_name(a1, a2,...ai);``
for all min_args <= i <= max_args, where x is a reference to an object of class type.
[endsect]
[section Example]
``
#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <boost/python/args.hpp>
#include <boost/python/tuple.hpp>
#include <boost/python/class.hpp>
#include <boost/python/overloads.hpp>
#include <boost/python/return_internal_reference.hpp>
using namespace boost::python;
tuple f(int x = 1, double y = 4.25, char const* z = "wow")
{
return make_tuple(x, y, z);
}
BOOST_PYTHON_FUNCTION_OVERLOADS(f_overloads, f, 0, 3)
struct Y {};
struct X
{
Y& f(int x, double y = 4.25, char const* z = "wow")
{
return inner;
}
Y inner;
};
BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(f_member_overloads, f, 1, 3)
BOOST_PYTHON_MODULE(args_ext)
{
def("f", f,
f_overloads(
args("x", "y", "z"), "This is f's docstring"
));
class_<Y>("Y")
;
class_<X>("X", "This is X's docstring")
.def("f1", &X::f,
f_member_overloads(
args("x", "y", "z"), "f's docstring"
)[return_internal_reference<>()]
)
;
}
``
[endsect]
[endsect]
|
