From: "David A. Black" <dblack@...>
Date: 2007-10-28T05:49:25+09:00
Subject: Re: .each do |foo, bar| what does bar do?

Hi --

On Sun, 28 Oct 2007, 7stud -- wrote:

> Brian Adkins wrote:
>> On Oct 27, 7:05 am, "David A. Black" <dbl...@rubypal.com> wrote:
>>>        i += 1
>>>      end
>>>      self
>>>    end
>>> end
>>
>> Or this:
>>
>> class Hash
>>   def each
>>     each_key {|key| yield key, self[key] }
>>   end
>> end
>>
>
>
> That suffers the same problem as David Black's example.

What problem did mine suffer from?

> That example has raised a question of my own.  Instead of having to
> write:
>
> def each(&block)
>    orig_each(&block)
>
> why can't I relay the block to orig_each() without the second '&', like
> this
>
> def each(&block)
>    orig_each(block)
>
> According to pickaxe2, p56, the '&' method converts the specified block
> to a Proc object and assigns it to the parameter variable 'block'.  Why
> is the second call to '&' required?

Because there's a difference between passing a Proc around as an
object, and supplying a code block to a method. You can do both:

   meth(arg,&block)

and arg can be a Proc object. So there has to be some way to tell the
method what you're doing.


David

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