From: Dan Sugalski <dan@...>
Date: 2002-01-03T11:21:16+09:00
Subject: [ruby-talk:30097] Re: Parrot (was re, Python and Ruby: a   comparison)

At 11:13 AM 1/3/2002 +0900, Rich Kilmer wrote:
> > From: Dan Sugalski [mailto:dan@sidhe.org]
> > At 05:02 AM 1/3/2002 +0900, Erik B�gfors wrote:
> > >On Tue, 2002-01-01 at 21:07, Dan Sugalski wrote:
> > > > >* How will blocks be used from other languages that doesn't
> > do blocks??
> > > >
> > > > You're talking semi-standalone chunks of code that can be
> > executed as a
> > > > sort of anonymous subroutine or method, right? Perl and
> > Python both have
> > > > those. If a language doesn't have 'em, then it can't call
> > into a function
> > > > that requires one. Not much to be done about that. (Though I
> > don't see it
> > > > as a problem--the inter-language calling conventions define
> > how you call
> > > > from one language to another, they don't require any language
> > to actually
> > > > implement everything the convention allows)
> > >
> > >Well.  The way blocks and iterators are used in ruby is not like it is
> > >in perl (I don't know python very well but I don't know of anything like
> > >that.
> > >
> > >for example:
> > >myObject.each { |x| puts x }
> > >
> > >How would that code look in perl(6) or python??
> >
> > An interesting question, but from the interpreter's standpoint not an
> > important one. :)
> >
> > For this example, the code in the {} would get turned into an anonymous
> > function, which the interpreter would then execute for each
> > element of the
> > list myObject.each generates.
>
>One issue is that Ruby's blocks carry with them the context of where they
>were called so if you had this:
>
>x = 2
>myObject.each { |p| puts p*x}
>
>Is that possible with Parrot?  Can your functions be defined with a local
>scope of some context?

Sure. Parrot's got full closure support slated for inclusion. The block 
would be a little anonymous closure, so you'd have your lexical scope 
available. (Well, I suppose it could be a full continuation, or a coroutine 
block, as need be)

					Dan

--------------------------------------"it's like this"-------------------
Dan Sugalski                          even samurai
dan@sidhe.org                         have teddy bears and even
                                      teddy bears get drunk