From: Trans <transfire@...>
Date: 2005-11-18T13:27:18+09:00
Subject: Re: Keyword arguments like grandma makes 'em


rcoder wrote:
> > I'm not sure that's neccessarily true. Yes it is true for 'and' and
> > 'or' and a few others, but 'alias', 'begin' and other aren't really
> > useful in the context of arguments, so they could still be used.
>
> And how, exactly, would you decide which keywords were and weren't
> useful in method argument context, given that just about everything
> aside from basic assignment in Ruby is based on method calls? Something
> about that smells awfully Pythonic to me...

Well, 'alias' isn't a method. In fact I think it should be gotten rid
of. #alias_method is a method and thus is preferable.

begin...end clauses aren't methods either and I don't see any good
reason to ever make them so. Yet I point out #begin and #end are
methods of MatchData. So I think these can be resused for keywords
arugments witouht issue.

if, case, until, loop, while, for: Except perhaps for 'for' I don't see
these as much of a loss if they couldn't be used for keywords args. In
fact 'if' and 'case' and 'while' I think make esspecially poor keywords
anyway. OTOH, they are rarely used for return values anyway, and
exponetially less so as direct method arguments. In fact I can't think
of a single time I ever used a condition or loop construct as an
argument.  Sso that's the other possibility, and again not much a loss
(if any) here either.

> One of my favorite aspects of Ruby's syntax is that *every* syntactic
> structure is an expression which returns a useful value. While you
> might not want to have a full 'case' switch tree inside the arglist,
> the syntax does not prohibit it.

Well. That's not completely true. But it'ss certainly close. I think
the not wanting a 'case' switch as an argument is pretty much
universally desired. No one wants to read code like that --actaully we
wouldn't have blocks if we wanted code like that. So prohibiting it I
doubt anyone would even notice.

> Making the overall syntax significantly more restrictive in order to
> eliminate a single character sigil for keyword args (which, since most
> methods require very few arguments, should be used only in the minority
> of cases) is still a bad trade in my book.

One sigil? When used once. In the course of an application one becomes
thousands.

Morevoer, it's not a bad trade at all when you also consider colon to
colon syntax ugliness.

> Of course, for people coming to Ruby via Rails, I can see the appeal of
> making keyword args as easy to use as possible, since the Rails team
> seems to have a real fetish for having single "do-it-all" methods that
> dispatch based on an arbitrary number of optional keyword args.

Perhaps a little overdone, but it's useful.

I'm not coming from Rails BTW. I've been here awhile.

T.