I look at those commas and wonder why? Is there a reason other than "must keep separators from normal function call"?

Labeled parameters are optional. In fact they're so optional, that you don't even have to label all of the parameters at a call site (just the ones that appear after the first labeled parameter).

So with that (mis)feature, eliding commas would make a lot of code harder to reader.

> So with that (mis)feature, eliding commas would make a lot of code harder to reader.

Not really. Lisps get by without them and it doesn't have formal keyword parameters.

True, but that's an advantage of Lisp's uniformity. Imagine passing a query comprehension (or two) as arguments.

    Foo(from n in range select n * n into: from n in range where n % 2 == 0 select n)

it kind of helps me visually dissect the parameters better - I'm sure if I got used to omitted commas it wouldn't be that big of a deal. When I would run into ruby code that omitted the parenthesis on a function call, it was considerably tougher to read for me.

Or, for that matter, Javascript, if you write it like this:

  aRect.Draw({x:50, y:50, width:10, height:21})