[Ironruby-core] A nicer syntax for generic extension methods

Ivan Porto Carrero ivan at whiterabbitconsulting.eu
Wed Feb 3 11:59:16 EST 2010


hashes?

but may i ask why you're so hell-bent on linq?  Linq is a really bad match
to ruby with the expressions. it would require some significant amount of
work to get that to work correctly.  AFAIK there is no way in IronRuby to
build expressions except use the raw API, but nothing is in there yet that
makes this easier to do.

Anyway you can reuse anonymous types did you know that? Alex James learnt
the trick from Wes Dyer
http://blogs.msdn.com/alexj/archive/2007/11/22/t-castbyexample-t-object-o-t-example.aspx


---
Met vriendelijke groeten - Best regards - Salutations
Ivan Porto Carrero
Blog: http://flanders.co.nz
Twitter: http://twitter.com/casualjim
Author of IronRuby in Action (http://manning.com/carrero)



On Wed, Feb 3, 2010 at 4:52 PM, Ryan Riley <ryan.riley at panesofglass.org>wrote:

> I just thought of something else. How do you deal with anonymous types in
> IronRuby? We don't have the type name when writing the code. Do we have to
> create at least a Ruby type for everything returned from an
> Enumerable.Select? I suppose that's where the module wrapper over LINQ would
> perhaps come in handy?
>
> Ryan Riley
>
> Email: ryan.riley at panesofglass.org
> LinkedIn: http://www.linkedin.com/in/ryanriley
> Blog: http://wizardsofsmart.net/
> Twitter: @panesofglass
> Website: http://panesofglass.org/
>
>
> On Wed, Feb 3, 2010 at 9:31 AM, Ryan Riley <ryan.riley at panesofglass.org>wrote:
>
>> Okay, just posted a rough first stab at the topic. This is all generic
>> delegates, too; I haven't bothered with plain old generics. :) Please let me
>> know if you have any feedback. I will add the stuff Tomas noted above when I
>> get a chance a little later.
>>
>> http://ironruby.net/Documentation/.NET/Delegates
>> <http://ironruby.net/Documentation/.NET/Delegates>
>> Ryan Riley
>>
>> Email: ryan.riley at panesofglass.org
>> LinkedIn: http://www.linkedin.com/in/ryanriley
>> Blog: http://wizardsofsmart.net/
>> Twitter: @panesofglass
>> Website: http://panesofglass.org/
>>
>>
>> On Wed, Feb 3, 2010 at 9:01 AM, Ryan Riley <ryan.riley at panesofglass.org>wrote:
>>
>>> Thanks, Ivan. That's awesome ... that's just like F#. I should have
>>> realized it would be that simple. I'll post this to the Delegates section of
>>> the .NET interop page on the wiki, since it currently doesn't exist.
>>>
>>> Also, I noticed you alluded to something similar in IronRuby in Action
>>> where you talk about LightSpeed, but I couldn't find anything in the MEAP
>>> copy I have. If I am able to spin up a few LINQ samples (probably Rx, Pfx,
>>> and/or XLinq), I'll shoot them your way, if you are interested.
>>>
>>> Cheers!
>>>
>>> Ryan Riley
>>>
>>> Email: ryan.riley at panesofglass.org
>>> LinkedIn: http://www.linkedin.com/in/ryanriley
>>> Blog: http://wizardsofsmart.net/
>>> Twitter: @panesofglass
>>> Website: http://panesofglass.org/
>>>
>>>
>>> On Tue, Feb 2, 2010 at 11:40 PM, Ivan Porto Carrero <
>>> ivan at whiterabbitconsulting.eu> wrote:
>>>
>>>> just pass your block to the constructor of a delegate and you should be
>>>> good to go
>>>>
>>>> Action.new { more_work_here }
>>>> ---
>>>> Met vriendelijke groeten - Best regards - Salutations
>>>> Ivan Porto Carrero
>>>> Blog: http://flanders.co.nz
>>>> Twitter: http://twitter.com/casualjim
>>>> Author of IronRuby in Action (http://manning.com/carrero)
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Feb 2, 2010 at 11:38 PM, Ryan Riley <
>>>> ryan.riley at panesofglass.org> wrote:
>>>>
>>>>> That's fantastic, Tomas, thanks! Is there any way to pass a block,
>>>>> lambda, or Proc into the slot for the delegate, or perhaps a way to create a
>>>>> .NET delegate (or Expression) from a block, lambda, or Proc?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Ryan Riley
>>>>>
>>>>> Email: ryan.riley at panesofglass.org
>>>>> LinkedIn: http://www.linkedin.com/in/ryanriley
>>>>> Blog: http://wizardsofsmart.net/
>>>>> Twitter: @panesofglass
>>>>> Website: http://panesofglass.org/
>>>>>
>>>>>
>>>>> On Tue, Feb 2, 2010 at 1:36 AM, Tomas Matousek <
>>>>> Tomas.Matousek at microsoft.com> wrote:
>>>>>
>>>>>> Actually, you can add Ruby methods to List<T> … IronRuby type system
>>>>>> does some magic for you J:
>>>>>>
>>>>>>
>>>>>>
>>>>>> >>> include System::Collections::Generic
>>>>>>
>>>>>> => Object
>>>>>>
>>>>>> >>> List[Fixnum].included_modules
>>>>>>
>>>>>> => [System::Collections::Generic::List[T],
>>>>>> System::Collections::Generic::IList[Fixnum],
>>>>>> System::Collections::Generic::IList[T],
>>>>>> System::Collections::Generic::ICollection[Fixnum],
>>>>>> System::Collections::Generic::ICollection[T],
>>>>>> System::Collections::Generic::IEnumerable[Fixnum],
>>>>>> System::Collections::Generic::IEnumerable[T],
>>>>>> System::Collections::IEnumerable, Enumerable, System::Collections::IList,
>>>>>> System::Collections::ICollection, System::Collections::Generic, Kernel]
>>>>>>
>>>>>>
>>>>>>
>>>>>> As you can see the List<> generic type definition is treated as a
>>>>>> module that is mixed in each of its instantiations. Although there are no
>>>>>> predefined methods on it you can open it and add some. First we need to get
>>>>>> Ruby class for List<T>. If you index System.Collections.Generic.List by a
>>>>>> fixnum instead of a class/module you’ll get the generic definition of arity
>>>>>> 1. Let’s name it ListOfT:
>>>>>>
>>>>>>
>>>>>>
>>>>>> >>> ListOfT = List[1]
>>>>>>
>>>>>>
>>>>>>
>>>>>> And then we can open it up:
>>>>>>
>>>>>>
>>>>>>
>>>>>> >>> module ListOfT
>>>>>>
>>>>>> ...   def size
>>>>>>
>>>>>> ...     count
>>>>>>
>>>>>> ...   end
>>>>>>
>>>>>> ... end
>>>>>>
>>>>>> => nil
>>>>>>
>>>>>> >>> l = List[Fixnum].new
>>>>>>
>>>>>> => []
>>>>>>
>>>>>> >>> l.add(1)
>>>>>>
>>>>>> => nil
>>>>>>
>>>>>> >>> l.add(2)
>>>>>>
>>>>>> => nil
>>>>>>
>>>>>> >>> l.size
>>>>>>
>>>>>> => 2
>>>>>>
>>>>>>
>>>>>>
>>>>>> Tomas
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *From:* ironruby-core-bounces at rubyforge.org [mailto:
>>>>>> ironruby-core-bounces at rubyforge.org] *On Behalf Of *Orion Edwards
>>>>>> *Sent:* Monday, February 01, 2010 6:31 PM
>>>>>> *To:* ironruby-core at rubyforge.org
>>>>>> *Subject:* Re: [Ironruby-core] A nicer syntax for generic extension
>>>>>> methods
>>>>>>
>>>>>>
>>>>>>
>>>>>> IIRC you can open "concrete" generics, but not "open" ones: In plain
>>>>>> english this means you can add methods to List<string> but not List<T>.
>>>>>>
>>>>>>
>>>>>>
>>>>>> This is essentially because List<T> isn't a real type in the CLR, it's
>>>>>> basically some metadata that can be used to build a real type when the T is
>>>>>> supplied.
>>>>>>
>>>>>>
>>>>>>
>>>>>> You could as an alternative add methods to the underlying non-generic
>>>>>> IEnumerable interface, but then you'd have to do some run-time reflection to
>>>>>> figure out that your List is actually a List<string>... This is probably not
>>>>>> nice.
>>>>>>
>>>>>>
>>>>>>
>>>>>> In theory when CLR4 lands and has support for co/contra variant
>>>>>> generics, List<object> should match List<string> and everything else, but I
>>>>>> don't know if IronRuby would also work for this?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Good luck
>>>>>>
>>>>>> On Tue, Feb 2, 2010 at 7:52 AM, Ryan Riley <
>>>>>> ryan.riley at panesofglass.org> wrote:
>>>>>>
>>>>>> I have been trying to figure out how to Rubify generic extension
>>>>>> methods for use with the likes of Rx, Open XML SDK, etc. Ivan went over it a
>>>>>> bit with me this weekend, but I'm still having difficulty including a module
>>>>>> within a .NET type. Is that even possible?
>>>>>>
>>>>>>
>>>>>>
>>>>>> ...
>>>>>>
>>>>>>
>>>>>>
>>>>>> The questions I'm not able to answer are:
>>>>>>
>>>>>>    1. Can I somehow open up a .NET class, say
>>>>>>    System::Collections::Generic::List[T] and include the EnumerableExtensions?
>>>>>>    So far, I'm finding that's a no.
>>>>>>    2. How do I hook in the included(base) method above? I'm assuming
>>>>>>    that's a one-time call, but I don't see anywhere that it's called when a
>>>>>>    module is included. Do I need to use a before_filter or perform that action
>>>>>>    at the beginning of the linq_select method?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks!
>>>>>>
>>>>>>
>>>>>> Ryan Riley
>>>>>>
>>>>>> Email: ryan.riley at panesofglass.org
>>>>>> LinkedIn: http://www.linkedin.com/in/ryanriley
>>>>>> Blog: http://wizardsofsmart.net/
>>>>>> Twitter: @panesofglass
>>>>>> Website: http://panesofglass.org/
>>>>>>
>>>>>> _______________________________________________
>>>>>> Ironruby-core mailing list
>>>>>> Ironruby-core at rubyforge.org
>>>>>> http://rubyforge.org/mailman/listinfo/ironruby-core
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> Ironruby-core mailing list
>>>>>> Ironruby-core at rubyforge.org
>>>>>> http://rubyforge.org/mailman/listinfo/ironruby-core
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Ironruby-core mailing list
>>>>> Ironruby-core at rubyforge.org
>>>>> http://rubyforge.org/mailman/listinfo/ironruby-core
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> Ironruby-core mailing list
>>>> Ironruby-core at rubyforge.org
>>>> http://rubyforge.org/mailman/listinfo/ironruby-core
>>>>
>>>>
>>>
>>
>
> _______________________________________________
> Ironruby-core mailing list
> Ironruby-core at rubyforge.org
> http://rubyforge.org/mailman/listinfo/ironruby-core
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://rubyforge.org/pipermail/ironruby-core/attachments/20100203/2b720620/attachment-0001.html>


More information about the Ironruby-core mailing list