[C++-sig] Re: Some questions ...

[Mike Thompson]

"David Abrahams" wrote:
> "Mike Thompson" writes:
>
> > Q2.  The following function works, but I'm left wondering if there's not a
> >          better way.  It takes a list of ints and returns the equivalent
> > vector<int>.
> >
> >          vector<int>  makeVectorFromList(list l)
> >          {
> >              boost::python::object olen = l.attr("__len__")();
> >              int len = extract<int>(olen)();
> >
> >              vector<int> ret(len);
> >
> >              for (int i = 0; i < len; ++i) {
> >                  extract<int>  get_int(l[i]);
> >                  if (!get_int.check()) {
> >                      PyErr_SetString(PyExc_TypeError, "makeVectorFromList()
> > expects a list of ints");
> >                      throw error_already_set();
> >                  }
> >                  ret[i] = get_int();
> >              }
> >             return ret;
> >          }
>
> What about that approach would you like to see improved?  In other
> words, why are you left wondering if there's a "better way"?
>

I was wondering if I was missing a bit of existing magic like, say, this:

    vector<int> v = extract<vector<int> > (l)();

Except, of course, I tried that and it didn't work.

But I kept wondering if, by writing this function, I was reinventing a wheel
already built, probably more elegantly.

So I asked.

--
Mike