From: Daniel Amelang <daniel.amelang@...>
Date: 2005-03-31T10:17:51+09:00
Subject: Re: New block syntax

Hey David, I think that we've had some misunderstandings due to
talking about different ruby versions. Some of the concerns that
you've brought up are not a part of the proposed new hash syntax ([:],
etc), but part of the new hash construct already in 1.9. I addressed
one of those concerns in an email I sent to this list last week:

http://ruby-talk.org/cgi-bin/scat.rb/ruby/ruby-core/4614

But I see another misunderstanding now. Forget the whole [hash] idea
for the moment and let's just use the current 1.9 {key:value} syntax
(with the {}, you notice). You're example:

a = SomeClass.new
b = 100

{a:'apple', b:'orange'}

would give you {:a=>'apple', :b=>'orange'}. If you want the 'a' and
'b' to refer to the _objects_ that 'a' and 'b' refer to, not the
symbols :a and :b, you can't use the ':' syntax, you have to fall back
on the => syntax. That has been a part of 1.9 for a while now (AFAIK).

>All of this just seems like so much upheaval to avoid the
>(comparatively unusual [compared to hash literals, that is]) keyword
>'lambda'.

Actually, so far, your points have been against the {:} syntax, which
has it's origins far before the whole no-lambda proc syntax idea.

Just want to make sure that we're on the same page.

Dan
 





On Wed, 30 Mar 2005 22:04:52 +0900, David A. Black <dblack@wobblini.net> wrote:
> Hi --
> 
> On Wed, 30 Mar 2005, Sean E. Russell wrote:
> 
> > On Monday 21 March 2005 16:17, David A. Black wrote:
> >
> >> whitespace would be required before a symbol argument to a method, and
> >
> > Isn't it already?  Whitespace, or a token character, is required before a
> > symbol argument, AFAIK.  Are you looking at a different version of Ruby than
> > I am?
> 
> Possibly.
> 
>    $ ruby -ve 'def x(y); p y; end; x:a'
>    ruby 1.8.2 (2004-12-25) [i686-linux]
>    :a
> 
> (It may have changed in one or more 1.9's, but I'm treating it, like
> all of this, as in flux and under discussion.)
> 
> >> so on.  So writing a Hash correctly would involved threading a much
> >> narrower needle.
> >
> > Any reduction of typing does this, but that isn't an argument for having a
> > terse syntax.
> 
> I don't quite follow.
> 
> > Ruby has always played it fast and loose.  This syntax isn't
> > more obfuscated; it is still clear what is being meant with:
> >
> >    h = [ one: 'me', two: 'you', something: 'else' ]
> >
> > Well, at least, to me this seems pretty natural, and much easier to type than
> > hashes defined with =>, and much clearer than hashes defined with ','.  With
> > long comma-separated hashes, it can be difficult to associate keys with
> > values; this syntax is more clear.
> 
> Except for the [] part :-)  That's the thing: I'm really talking about
> the {} constructor, and the implications of pressing [] into service
> as a part-time hash literal.  I don't feel strongly about the commas,
> except that for tests it's nice to type h = { 1,2,3,4 }, since it's
> fast.
> 
> 
> David
> 
> --
> David A. Black
> dblack@wobblini.net
> 
>