Support keyword-only arguments

[pekkaklarck]

RF 3.1 got support for keyword-only arguments (robotframework/robotframework#2555) and also the dynamic API supports them (robotframework/robotframework#2897). PythonLibCore should support them as well.

[aaltat]

There is something that I do not see but for me it looks like kwargs are supported. I added tests in #32 and all works. Should this be closed?

[pekkaklarck]

This isn't about keyword arguments only, this is about keyword-only arguments. 😄

**kwargs works just fine with Python 2 and with RF 2.9+. I would expect there to be tests for it with PythonLibCore as well but I may be wrong.

[aaltat]

Ah that we support def method (*varargs, something=False) in PythonLibCore. Yes that is not supported.

[aaltat]

So how should the get_keyword_argumentsreturn if keyword method looks like: def method (*varargs, something=False)? Something like this with RF 3.2 syntax: ["*varargs", ("something", bool)]

[pekkaklarck]

That looks right to me. But to be honest, I think I forgot to tests this default syntax with kwonly args. I expect/hope the code to work but need to add those tests anyway. Hopefully you can also add some acceptance tests to PyLibCo that test this end-to-end.

[aaltat]

And if I have this:

def foo(self, *varargs, other)
    pass

I should return ["*varargs", "other"]. Need to think how handle all this.

[pekkaklarck]

Yes, kwonly args without default values should to be handled like that. Need to handle this case as well:

def bar(*, kwo):
    pass

As I recommended elsewhere, it probably would be a good idea to have an ArgumentSpec objcet that contains all this information and can then turned to a list of arguments. Assuming the spec object had same attributes as similar object on Robot side, something like this could work:

def __iter__(self):
    for arg in self.positional:
        yield self._arg_with_possible_default(arg)
    if self.varargs:
        yield '*' + self.varargs
    elif self.kwonlyargs:
        yield '*'
    for arg in self.kwonlyargs:
        yield self._arg_with_possible_default(arg)
    if self.kwargs:
        yield '**' + self.kwargs

def _arg_with_possible_default(self, arg):
    if arg not in self.defaults:
        return arg
    arg_and_default = (arg, self.defaults[arg])
    if RF31:
        return '%s=%s' % arg_and_default
    return arg_and_default

[aaltat]

What, def bar(*, other): is valid syntax. Did not know that one -> more tests required. Any other strange things that would be good to know?