From: David Alan Black <dblack@...>
Date: 2002-04-28T06:38:17+09:00
Subject: Re: $_ if no |var|

Hi --

On Sun, 28 Apr 2002, Lars Christensen wrote:

> On Sun, 28 Apr 2002, David Alan Black wrote:
>
> > I have to confess that to me it just doesn't look or feel like Ruby.
> > I know that's very vague... that's why I was trying to come up with a
> > case illustrating the importance (or at least Ruby-ness) of all the
> > assignments being made, independent of any branching within the code
> > of the block.
>
> I think you are right--I think I would 'expect' all assignments to be
> made.  I.e.
>
>    proc { if |a| then |b| else |c| end }
>
> should only be syntatic sugar for
>
>    proc { |a,b,c| if a then b else c end }
>
> or, equivalently
>
>   proc { |p| a,b,c=p; if a then b else c end }
>
> The |a| would just be syntax to mark which symbols should be bound to the
> arguments when the block is evaluated.

I honestly don't think this syntax can scale beyond trivial cases.
You're talking about binding variables in the order they're used in
the block, rather than binding them in a particular order and then
using them.  I think there's a major impedance mismatch between this
idea and the possibilities of Ruby syntax.

Consider, for example:

  proc { |a,b,c| if a then b else c }
  proc { |a,b,c| unless a then c else b }

which are equivalent.  But these:

  proc { if |arg1| then |arg2| else |arg3| }
  proc { unless |arg1| then |arg2| else |arg3| }

would not be.

Could it be there's a reason that most (all?) languages grab their
method/function/proc parameters up front? :-)


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav