On Fri, Mar 23, 2012 at 4:44 AM, csd <charan...@gmail.com> wrote:
> I wanted to wrap some C++ code using Cython (to be callable in Python)
> and wondered if one could specify the template type in Python itself
> somehow. To illustrate the problem, consider the code which wraps the C
> ++ vector class in Cython (taken from http://docs.cython.org/src/userguide/wrapping_CPlusPlus.html
> )

> from cython.operator cimport dereference as deref, preincrement as inc
> #dereference and increment operators

> cdef extern from "<vector>" namespace "std":
>    cdef cppclass vector[T]:
>        cppclass iterator:
>            T operator*()
>            iterator operator++()
>            bint operator==(iterator)
>            bint operator!=(iterator)
>        vector()
>        void push_back(T&)
>        T& operator[](int)
>        T& at(int)
>        iterator begin()
>        iterator end()

> Ideally I would like to make this code callable from Python using
> something like:

> a = PyVector(int)

> where int becomes the template type.

> My incorrect attempt so far looks like this:

> cdef class PyVector:
>    cdef vector[T] *thisptr      # hold a C++ instance which we're
> wrapping
>    def __cinit__(self, tempType):
>        self.thisptr = new vector[tempType]()

> but I need to specify the template type of the instance variable
> before the constructor. One way to get around it is to hard-code
> several types in different classes, and then choose one in the
> constructor of PyVector, but this isn't ideal. Any ideas?