clean up some unnecessary C-API usages and fix integer sizes

[scoder]

note: integer size fixes which require corresponding changes in itertoolz.pxd

[eriknw]

Awesome, everything in here looks great. I am a little abashed at writing such dirty code in the first place, so thanks for cleaning it up! I'd like to look at this a little more closely, but I think we can get this merged very soon.

By the way, @scoder, I think you've done a fantastic job with lupa. Merging Lua and Python is one of my guilty pleasures. When writing complicated functionality for Lua, I find I prefer to first write it in Python along with a test suite, and then it's trivial to port it to Lua and test it from within Python. Thanks!

[eriknw]

Additional bindings go in "cytoolz/cpython.pxd".

I would actually like to use different names for the C API functions defined in that file. For example, perhaps function names should use PyPointer_ prefix if the new binding returns a pointer, such as:

cdef extern from "Python.h":
    PyObject* PyPointer_GetItem "PyObject_GetItem" (object o, object key)

Is this common practice, and what naming conventions make sense?

[scoder]

Additional bindings go in "cytoolz/cpython.pxd".

I'm aware of that, just thought you might want to have some fun cleaning more things up, too. :)

Note that there are lots of similar cases in the other modules where writing explicit C-API calls can be avoided. As a rule of thumb, I'd always write things down in Python syntax first, and then look at the C code ("cython -a module.pyx" will give you an HTML view on it, especially nice with the latest Cython master branch and Pygments installed). Only if Cython happens to generate suboptimal code, I'd consider working around that. In many cases, adding a hint like "this isn't None" or an explicit assignment will already help enough.

PyPointer_GetItem

Something like PyObject_GetItemPointer() or ...Ptr() sounds better to me. I don't think there is a convention. I agree that it's better to distinguish the names. Looking through the code, I often went "why is the author calling that function here instead of just using normal Python syntax?" and in some cases, it was because the code was actually lying to me and doing something different from what it said.

[eriknw]

I'm aware of that, just thought you might want to have some fun cleaning more things up, too. :)

I plan to, and thanks for getting this started :) . I agree with your rules of thumbs (and all of your changes), and I know I didn't look at the annotated output ("cython -a") nearly often enough.

A brief history: this project began as a way for me to get my hands dirty with Cython, and I became curious how much toolz could be improved. I didn't know cytoolz was going to be the result! @mrocklin just gave a talk at PyData yesterday that included CyToolz, and I did well to match Toolz' API and to make it pip-installable in a limited amount of time. So, yes, I expect that a little cleaning and revision may be needed, and I greatly appreciate the feedback and contributions that have already been given.

Something like PyObject_GetItemPointer() or ...Ptr() sounds better to me. I don't think there is a convention. I agree that it's better to distinguish the names. Looking through the code, I often went "why is the author calling that function here instead of just using normal Python syntax?" and in some cases, it was because the code was actually lying to me and doing something different from what it said.

Yeah, we should definitely use different and more descriptive names. There aren't many additional C bindings, so I guess it's too soon to come up with conventions as long as the name of each individual binding makes sense.

[eriknw]

Merging.

[mrocklin]

Thanks @scoder !