From: Sean O'Halpin <sean.ohalpin@...>
Date: 2011-03-14T01:18:16+09:00
Subject: Re: send() with a block?

On Sun, Mar 13, 2011 at 2:54 PM, Peter Zotov <whitequark@whitequark.org> wrote:
> On Sun, 13 Mar 2011 23:26:01 +0900, Brian Candler wrote:
>>
>> Peter Zotov wrote in post #987115:
>>>
>>> On Sun, 13 Mar 2011 06:01:31 +0900, Sean O'Halpin wrote:
>>>>
>>>> define_method().
>>>>
>>>
>>>  But send() still bothers to pass the block around. Consider the
>>>  following code:
>>>
>>>  ---8<---8<---
>>>  def my_method
>>>   p block_given?
>>>  end
>>>
>>>  def my_send # imitating send
>>>   my_method
>>>  end
>>>
>>>  my_send # => false
>>>  ---8<---8<---
>>
>> But compare with this:
>>
>> def my_method
>>  p block_given?
>> end
>>
>> def my_send(&blk) # imitating send
>>  my_method(&blk)
>> end
>>
>> my_send # => false
>> my_send { :wibble } # => true
>
> That's the whole point of my demonstration. (Maybe I was too concise.)

You were so concise you left out the thing you were trying to demonstrate:

def my_send
  p block_given?
end

my_send { p 42 } #=> true

> Any send-like method should to a trick like that to get the block-passing
> behavior. It is not implicit.

It /is/ implicit and is true for any method call. That's how you can do this:

def my_yield
  yield
end

my_yield { p 42 } #=> 42

You specify the &block parameter when you want to do something with the block.

Regards,
Sean