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comp.lang.ruby

Perspectives for Ruby 2.0

arcadio

5/26/2007 4:18:00 PM

Hi,

I'm quite new to Ruby. First of all I must say that Ruby has shocked
me ever since I discovered it. IMO Ruby has the elegant message
passing of Smalltalk, some of the dynamism of Dylan and some great
functional features. Everything with a compact Perl-like synthax,
clean and readable though.

I would like to pose two questions regarding features I think Ruby
should include in the future:

1. Are there any plans to introduce function currying? It's a very
useful feature for function expressions, and it won't be very
difficult to add. In fact, far I've seen a few implementations of it
out there. They seem to be more or less ok, but it would be great to
have it on the standard distribution.


2. What about aspect-oriented programming on Ruby? I know about
AspectR. However, the project seems to be no more on active
development. Am I right?

Ruby community has always been very receptive to new ideas. It would
be great to build a solid AOP extension. This could position Ruby with
a clear advantage over many languages.

IMO, AspectJ, which is the defacto AOP language is dead end. I worked
on the AspectJ Compiler project some time ago, and it's a nightmare.
Things become *SO* complex and buggy when trying to deal with
generics. And I don't want to think about future closures of Java 1.7.
In contrast, an AOP extension for Ruby could be very several levels of
magnitude easier.


Thanks,

Arcadio
12 Answers

Alexey Verkhovsky

5/26/2007 6:32:00 PM

0

On 5/26/07, arcadiorubiogarcia@gmail.com <arcadiorubiogarcia@gmail.com> wrote:
> 2. What about aspect-oriented programming on Ruby?

AOP is a creative, massively complex workaround for the constraints of
static languages.

In Ruby, you can solve all the problems AOP solves, using just Ruby
interpreter and no external tools and libraries. Moreover, this
capability so naturally fits with the rest of the language, it doesn't
even need a name.

Welcome.

--
Alex Verkhovsky

Michael Hollins

5/27/2007 10:31:00 AM

0

arcadiorubiogarcia@gmail.com wrote:

>
> 1. Are there any plans to introduce function currying? It's a very
> useful feature for function expressions, and it won't be very
> difficult to add. In fact, far I've seen a few implementations of it
> out there. They seem to be more or less ok, but it would be great to
> have it on the standard distribution.

what would you want beyond the following?

http://moonbase.rydia.net/mental/blog/programming/curryi...

arcadio

5/27/2007 1:59:00 PM

0

On May 27, 12:31 pm, Michael Hollins <m...@hollins.id.au> wrote:
> arcadiorubiogar...@gmail.com wrote:
>
> > 1. Are there any plans to introduce function currying? It's a very
> > useful feature for function expressions, and it won't be very
> > difficult to add. In fact, far I've seen a few implementations of it
> > out there. They seem to be more or less ok, but it would be great to
> > have it on the standard distribution.
>
> what would you want beyond the following?
>
> http://moonbase.rydia.net/mental/blog/programming/curryi...

Well I would want something more implicit, like in Groovy for
instance:
http://www.ibm.com/developerworks/java/library/j-pg08235/...

Michael Hollins

5/28/2007 2:36:00 PM

0

arcadiorubiogarcia@gmail.com wrote:
> On May 27, 12:31 pm, Michael Hollins <m...@hollins.id.au> wrote:
>> arcadiorubiogar...@gmail.com wrote:
>>
>>> 1. Are there any plans to introduce function currying? It's a very
>>> useful feature for function expressions, and it won't be very
>>> difficult to add. In fact, far I've seen a few implementations of it
>>> out there. They seem to be more or less ok, but it would be great to
>>> have it on the standard distribution.
>> what would you want beyond the following?
>>
>> http://moonbase.rydia.net/mental/blog/programming/curryi...
>
> Well I would want something more implicit, like in Groovy for
> instance:
> http://www.ibm.com/developerworks/java/library/j-pg08235/...
>
>

So, just so I understand, take the following example:

def multiply(a,b)
a * b
end

triple = lambda { |a| multiply(a,3) }

puts triple.call(10)

I believe you are saying that you'd like the last line to be:

puts triple(10)

Is that right? If so, then I agree that would be nice. I'm guessing that it's difficult to achieve
in ruby due to the fact that functions can be called without the parentheses. So, for example if I
defined the following uninteresting lambda:

six = lambda { multiply(2,3) }

then the following would be ambiguous:

puts six

Am I trying to invoke the lambda, or am I trying to print the value of the object? To resolve the
ambiguity I cannot invoke a lambda with the above syntax. Instead I need to do:

puts six.call()

I'd like to hear from the experts if that is the reason or whether there is something more
fundamental. I'm still learning ruby (and liking it BTW), so others will likely have a clearer
perspective.

cheers,
mick

Ken Bloom

5/28/2007 2:40:00 PM

0

On Sun, 27 May 2007 06:58:55 -0700, arcadiorubiogarcia wrote:

> On May 27, 12:31 pm, Michael Hollins <m...@hollins.id.au> wrote:
>> arcadiorubiogar...@gmail.com wrote:
>>
>> > 1. Are there any plans to introduce function currying? It's a very
>> > useful feature for function expressions, and it won't be very
>> > difficult to add. In fact, far I've seen a few implementations of it
>> > out there. They seem to be more or less ok, but it would be great to
>> > have it on the standard distribution.
>>
>> what would you want beyond the following?
>>
>> http://moonbase.rydia.net/mental/blog/programming/curryi...
>
> Well I would want something more implicit, like in Groovy for instance:
> http://www.ibm.com/developerworks/java/library/j-pg08235/...

class Proc
def curry *curryargs
lambda{|*args| self.call(*(curryargs+args))}
end
end

--
Ken Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu...

Gregory Brown

5/28/2007 3:27:00 PM

0

On 5/28/07, Michael Hollins <mick@hollins.id.au> wrote:
> arcadiorubiogarcia@gmail.com wrote:

> triple = lambda { |a| multiply(a,3) }
>
> puts triple.call(10)
>
> I believe you are saying that you'd like the last line to be:
>
> puts triple(10)

We can already do puts triple[10], which gets you close.

Tomas Pospisek

5/28/2007 3:52:00 PM

0

Chris Carter

5/28/2007 4:45:00 PM

0

On 5/28/07, Tomas Pospisek's Mailing Lists <tpo2@sourcepole.ch> wrote:
> On Mon, 28 May 2007, Michael Hollins wrote:
>
> > arcadiorubiogarcia@gmail.com wrote:
> >> On May 27, 12:31 pm, Michael Hollins <m...@hollins.id.au> wrote:
> >>> arcadiorubiogar...@gmail.com wrote:
> >>>
> >>>> 1. Are there any plans to introduce function currying? It's a very
> >>>> useful feature for function expressions, and it won't be very
> >>>> difficult to add. In fact, far I've seen a few implementations of it
> >>>> out there. They seem to be more or less ok, but it would be great to
> >>>> have it on the standard distribution.
> >>> what would you want beyond the following?
> >>>
> >>> http://moonbase.rydia.net/mental/blog/programming/curryi...
> >>
> >> Well I would want something more implicit, like in Groovy for
> >> instance:
> >> http://www.ibm.com/developerworks/java/library/j-pg08235/...
> >>
> >>
> >
> > So, just so I understand, take the following example:
> >
> > def multiply(a,b)
> > a * b
> > end
> >
> > triple = lambda { |a| multiply(a,3) }
> >
> > puts triple.call(10)
> >
> > I believe you are saying that you'd like the last line to be:
> >
> > puts triple(10)
> >
> > Is that right? If so, then I agree that would be nice. I'm guessing that it's
> > difficult to achieve in ruby due to the fact that functions can be called
> > without the parentheses. So, for example if I defined the following
> > uninteresting lambda:
> >
> > six = lambda { multiply(2,3) }
> >
> > then the following would be ambiguous:
> >
> > puts six
> >
> > Am I trying to invoke the lambda, or am I trying to print the value of the
> > object? To resolve the ambiguity I cannot invoke a lambda with the above
> > syntax. Instead I need to do:
> >
> > puts six.call()
> >
> > I'd like to hear from the experts if that is the reason or whether there is
> > something more fundamental. I'm still learning ruby (and liking it BTW), so
> > others will likely have a clearer perspective.
>
> The ambiguity is there allready
>
> If I write:
>
> puts nuts
>
> Then nuts can either be a variable that will return its value, or it can
> be a function call that will return the result of calling it. In that
> sense being able to call (from your example above):
>
> puts six
>
> would be IMHO perfectly sensible, since it would be neither more nor less
> ambiguous then ruby's default behaveour.
> *t
>
> --
> -----------------------------------------------------------
> Tomas Pospisek
> http://sour... - Linux & Open Source Solutions
> -----------------------------------------------------------
>
>

Yes, but a method is not an object, whereas a Proc is. So we don't
know if we want to inspect or call the Proc, it can be reasonably
assumed you want to call the method because, there is no way to
inspect the method without trapping it.

--
Chris Carter
concentrationstudios.com
brynmawrcs.com

John Wilger

5/28/2007 4:54:00 PM

0

On May 28, 9:44 am, "Chris Carter" <cdcar...@gmail.com> wrote:
> Yes, but a method is not an object

Well...it kind of is... http://ruby-doc.org/core/classes/M...

--
Regards,

John Wilger

Ken Bloom

5/28/2007 7:17:00 PM

0

On Tue, 29 May 2007 00:36:27 +1000, Michael Hollins wrote:

> arcadiorubiogarcia@gmail.com wrote:
>> On May 27, 12:31 pm, Michael Hollins <m...@hollins.id.au> wrote:
>>> arcadiorubiogar...@gmail.com wrote:
>>>
>>>> 1. Are there any plans to introduce function currying? It's a very
>>>> useful feature for function expressions, and it won't be very
>>>> difficult to add. In fact, far I've seen a few implementations of it
>>>> out there. They seem to be more or less ok, but it would be great to
>>>> have it on the standard distribution.
>>> what would you want beyond the following?
>>>
>>> http://moonbase.rydia.net/mental/blog/programming/curryi...
>>
>> Well I would want something more implicit, like in Groovy for instance:
>> http://www.ibm.com/developerworks/java/library/j-pg08235/...
>>
>>
>>
> So, just so I understand, take the following example:
>
> def multiply(a,b)
> a * b
> end
>
> triple = lambda { |a| multiply(a,3) }
>
> puts triple.call(10)
>
> I believe you are saying that you'd like the last line to be:
>
> puts triple(10)
>
> Is that right? If so, then I agree that would be nice.

The choice of syntax for calling the function also has nothing to do with
currying.

--
Ken Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu...