supporting python functions returning tuples would be _very_ useful about ocaml_python_bindgen

[UnixJunkie]

Supporting all the ocaml types (and their python equivalent) would be nice: int, char, float, bool, string.

[UnixJunkie]

I hereby confirm that a hacker (@mooreryan) killed this feature request.

[mooreryan]

Hey so what kind of function are you wrapping...could you put a little example?

And assuming that the python function returns an actual python tuple...how you would like to use it from the OCaml side? Converting tuples into something usable from the OCaml side is flexible in pyml...you can treat them as OCaml tuples, or lists, or arrays, or even as an abstract type, so I'm curious how you would like to use it.

Also, would it be mainly returning tuples, or letting tuples be parameters for functions as well?

Currently I deal with tuples like this or sometimes like this if you need functors. But I could see how a more "natural" support for tuples would be helpful...it's just a matter of finding a pleasant way to deal with them.

[UnixJunkie]

The functions were like these:

# assert(get_distances(m) == [(0, 1, 1),
#                             (0, 2, 2),
#                             (0, 3, 3),
#                             (0, 4, 2),
#                             (0, 5, 1),
#                             (1, 2, 1),
#                             (1, 3, 2),
#                             (1, 4, 3),
#                             (1, 5, 2),
#                             (2, 3, 1),
#                             (2, 4, 2),
#                             (2, 5, 3),
#                             (3, 4, 1),
#                             (3, 5, 2),
#                             (4, 5, 1)])
# assert(type_atoms(m) == [(6, 2, 1, 3, 0),
#                          (6, 2, 1, 3, 0),
#                          (6, 2, 1, 3, 0),
#                          (6, 2, 1, 3, 0),
#                          (6, 2, 1, 3, 0),
#                          (6, 2, 1, 3, 0)])

I was just looking for returning tuples, and the tuple values were all of the same type (int, in this example).
I think python tuples should be mapped to ocaml tuples by default (maybe some users will want
to translate them to list/array, but I feel this should not be the default).

[mooreryan]

Okay, I see now...yeah I've hacked together some basic tuple support, but not yet tuples within lists/arrays/seqs. I will play around with it some more and see if there is any weirdness when dealing with them in general.

[UnixJunkie]

I would really love to have tuples being supported, at least as return type of python functions.
They should be mapped to an ocaml tuple (type: 'a * 'b * 'c).
Of course, in the interface, we would fix those type variables to some concrete type (possibly any basic OCaml type: int, float, char, string, whatever).

[UnixJunkie]

As a kind of sponsorship, I can send you my copy of the book moneyball, if that interests you. :)

[mooreryan]

Haha, I do love moneyball. Anyway, tuple support is finally here, and in version 0.3.0! You can see some examples of usage here.

(Currently not on opam yet, but you could pin it.)

Let me know if this works for you!

[UnixJunkie]

Ok, I will test and let you know.