From: Rodrigo Rosenfeld Rosas <rr.rosas@...>
Date: 2011-01-20T23:17:47+09:00
Subject: [ruby-core:34661] Re: Ruby operator equivalent to Groovy's "?."

  Em 20-01-2011 05:35, Giuseppe Bilotta escreveu:
> On Thu, Jan 20, 2011 at 1:27 AM, Rodrigo Rosenfeld Rosas
> <rr.rosas@gmail.com>  wrote:
>> One of the few things I like in Groovy that Ruby doesn't support is the '?.'
>> operator. For instance:
>>
>> obj?.somePropertyName?.anotherGreatPropertyName?.anotherOne
>>
>> This is the same as:
>>
>> (obj == null ? null : (obj.somePropertyName == null ? null :
>> (obt.somePropertyName.anotherGreatPropertyName == null ? null :
>> obt.somePropertyName.anotherGreatPropertyName.anotherOne)))
>>
>> Unfortunately, this name cannot be used by Ruby since it accepts '?' as part
>> of a method name. I've seen some framework that declares a '_?' method for
>> doing this like 'obj._?.some_method._?.another_method'.
>>
>> I'm not sure what syntax would fit better for Ruby. I don't even know if
>> this is something the Ruby community is interested in as well, so I'd like
>> to hear your opinions on this feature.
> I think there's plenty of interest in such a feature, as it seriously
> cuts down on if or rescue clause. One interesting point about the Ruby
> syntax is that the ? is accepted in a method name, but not as a first
> character. So for future ruby versions we could extend the actual
> internal syntas with something like this:
>
> obj.?method.?method2.?etc
>
> i.e. swapping ? and . wrt to the Groovy syntax. However, I'm thinking
> that this syntax would better be reserved for checking for the method
> presence rather than for the nil'ness of the object (as in: call
> method if obj replies to method, otherwise return nil, etc)

Yes, I've thought on that '.?' syntax too, but I wasn't very comfortable 
with it too...

Maybe '&.' could fit. For instance, obj&.method could be assimilated to 
obj && obj.method. I don't know if that conflicts with what is current 
allowed in Ruby though.

I just opened the discussion to see if someone comes with better 
suggestions...

Best regards,

Rodrigo.