Rubymotion support for ruby 2.0 keyword arguments - rubymotion

Question

Does Rubymotion support ruby 2.0 keyword arguments? I have this method and it throws this error: syntax error, unexpected tSTRING_BEG, expecting tIDENTIFIER
def foo(message, offset: 20)
# Do something
end
I am using the following version of Ruby, but it doesnt seem to be working?
$ ruby -v
vruby 2.0.0p353 (2013-11-22 revision 43784) [x86_64-darwin13.0.2]

Answer 1

No.
RubyMotion was released before Ruby 2.0.0, but it needed keyword arguments to interoperate with Objective-C, for example to define callback/delegate methods. So it introduced keyword arguments based on one of existing keyword arguments proposals at the time:
def tableView(view, numberOfRowsInSection: section)
# ...
end
So in RubyMotion the argument keyword name (numberOfRowsInSection) is separate from the argument name (section), and if keyword is present in a signature, then it is required.
However, Ruby 2.0.0 decided to stick to a different design:
def foo(message, offset: 0)
# ...
end
Argument keyword name is the same as the argument name (offset), they always have a default value (0 here), and they are optional (you can call foo(message) without offset here).
This is a bit unfortunate. But I'm interested to see how will RubyMotion evolve to support Ruby 2.0.0 keyword arguments in future.

Answer 2

Yes.
Using the Ruby Motion developer center docs as a reference, here's an example that looks a lot like what you're trying to do.
class DrawingProxy
def drawAtPoint(point, withFont:font)
#str.drawAtPoint(point, withFont:font)
end
end
That link explains how Objective-C messages with selectors map to and from RubyMotion, which takes things in a slightly non-Ruby direction in that you can effectively have Ruby methods with identical names "overloaded" as long as they have unique selectors (arguments).
A more RubyMotion way to express your example is:
def foo(message, withOffset = 20)
# Do something
end
You were using ":" (call value) rather than "=" (declare default) syntax.