From: Charles Oliver Nutter <headius@...>
Date: 2011-10-27T02:51:51+09:00
Subject: [ruby-core:40414] Re: [ruby-trunk - Feature #5474][Assigned] keyword argument

More refinement below. I think we're on a good path here.

On Sun, Oct 23, 2011 at 7:53 AM, Yusuke Endoh <mame@tsg.ne.jp> wrote:
> �� ��def create_point(x, y, color: "white", size: 1)
> �� �� ��# keyword arguments ��^^^^^^^^^^^^^^^^^^^^^^^ here!
>
> �� �� ��p [x, y, color, size]
> �� ��end

Evan and I would like to see support for non-default keyword args. So
the following form would require that "size" be provided as a keyword
arg, and otherwise raise an ArgumentError:

def create_point(x, y, color: "white", size:)
...

The trailing ":" on an argument would then indicate that it's a
keyword arg, and the default value would not be necessary. I don't
think this would be any harder to parse, either, since there's no
valid production where "," follows ":".

Also, after talking with Evan, I think we're both optimistic that
Yusuke's proposal can be implemented with good performance...certainly
much better performance than constructing a full-on Hash object as is
the case today.

- Charlie