From: Rich Kilmer <rich@...>
Date: 2002-01-03T11:13:04+09:00
Subject: [ruby-talk:30093] Re: Parrot (was re, Python and Ruby: a  comparison)



> -----Original Message-----
> From: Dan Sugalski [mailto:dan@sidhe.org]
> Sent: Wednesday, January 02, 2002 6:50 PM
> To: ruby-talk ML
> Subject: [ruby-talk:30087] Re: Parrot (was re, Python and Ruby: a
> comparison)
>
>
> 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?

>
> As far as the interpreter's concerned, the steps are:
>
>    generate small anon function
>    call myObject's each method with anon function as parameter
>
> Now, of course the each method creates an array of elements and iterates
> across them, but that's all within Ruby code. The function called doesn't
> have to be Ruby code--it could be perl or python or scheme if you wanted.
>