From: "David A. Black" <dblack@...>
Date: 2008-11-29T01:03:35+09:00
Subject: [ruby-core:20153] Re: [Bug #797] bug or feature: local method ?

Hi --

On Sat, 29 Nov 2008, Francoys wrote:

> Diogo Lisboa wrote:
>> On Wed, Nov 26, 2008 at 4:32 PM, Francoys <francois.pr@videotron.ca> wrote:
>>
>>> declaring variables inside a method that are accessibles to all the
>>> nested methods.
>>>
>>
>> This isn't possible though.
>>
>> def foo
>>   bar = 10
>>   def gazonk
>>     p bar
>>   end
>> end
>>
>>
>>>> gazonk # => undefined local variable or method `gazonk'
>>>> foo  # => nil
>>>> gazonk # => undefined local variable or method `bar'
>>>>
>>
>>
>> This doesn't work because the chained method is in a whole new scope
>> which doesn't know anything about the outer method's local variables.
>>
>> But, however odd this functionality is, I think it would be useful for
>> the enclosing method to inherit the outer scope. You'd get something
>> like named closures, and calling `gazonk' after `foo' would be able to
>> print 10.
>>
>> However, this wouldn't be consistent, meaning, it should have to work
>> if you declared a local variable in a class definition and all the
>> methods would be aware of that; at this point, things get ugly.
>>
>> I think the idea of 'named closure' could be interesting (I don't know
>> what consequences this would have, but sounds like a feature more than
>> a bug). It beats returning lambdas in an array.
>>
>> Would you, enlightened ones, share your opinions on this? On the idea
>> of the local methods being a bug or feature, I don't think they count
>> much as a feature the way they currently are.
>>
>>
>> Diogo
>>
>>
>>
> Try this one:
>
> def foo
>  @bar = 10
>  def gazonk
>    print @bar
>  end
>  gazonk
> end
>
> foo

That's very different, though, because you're redefining your inner
method every time *any* instance of the class calls the outer method,
and you're using instance variables so there's no closure effect.

class C
   def x
     @a = 1
     def y
       p @a
     end
   end
end

c = C.new
c.x
c.y          # 1
d = C.new
d.y          # nil


David

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