commit 2686da8350812e35784a3600d45b3e7f91a2af0e
author Jason Rhinelander <jason@imaginary.ca> Sat Jan 21 23:42:14 2017 -0500
committer Wenzel Jakob <wenzel.jakob@epfl.ch> Tue Jan 31 17:24:41 2017 +0100
tree b07e0f0f9818618eff1144a2d3fe7f4ef82b3082
parent 102c94fc38369e6addf65078bd0f4346c07459d1

Add support for positional args with args/kwargs

This commit rewrites the function dispatcher code to support mixing
regular arguments with py::args/py::kwargs arguments.  It also
simplifies the argument loader noticeably as it no longer has to worry
about args/kwargs: all of that is now sorted out in the dispatcher,
which now simply appends a tuple/dict if the function takes
py::args/py::kwargs, then passes all the arguments in a vector.

When the argument loader hit a py::args or py::kwargs, it doesn't do
anything special: it just calls the appropriate type_caster just like it
does for any other argument (thus removing the previous special cases
for args/kwargs).

Switching to passing arguments in a single std::vector instead of a pair
of tuples also makes things simpler, both in the dispatch and the
argument_loader: since this argument list is strictly pybind-internal
(i.e. it never goes to Python) we have no particular reason to use a
Python tuple here.

Some (intentional) restrictions:
- you may not bind a function that has args/kwargs somewhere other than
  the end (this somewhat matches Python, and keeps the dispatch code a
  little cleaner by being able to not worry about where to inject the
  args/kwargs in the argument list).
- If you specify an argument both positionally and via a keyword
  argument, you get a TypeError alerting you to this (as you do in
  Python).