From: "John J. Franey" <jjfraney@...>
Date: 2007-06-15T03:16:00+09:00
Subject: Re: define_method to define a method to pass a block to another method



Paul Novak wrote:
> 
> On Jun 13, 9:40 am, "John J. Franey" <jjfra...@verizon.net> wrote:
>> I would like to define the following method, func, using define_method
>> instead of def:
>>
>> def func(i, &block)
>>  wblock(i, &block)
>> end
>>
>> def wblock(i, &block)
>>   yield(i)
>> end
>>
>> The following didn't work:
>>
>> # syntax error
>> define_method('func') do |i,&block|
>>   wblock(i, &block)
>> end
>>
>> # ruby expects a second parameter, not a block
>> define_method('func') do |i,block|
>>  wblock(i, &block)
>> end
>>
>> Any ideas?
>>
>> Thanks
>> --
>> View this message in
>> context:http://www.nabble.com/define_method-to-define-a-method-to-pass-a-bloc...
>> Sent from the ruby-talk mailing list archive at Nabble.com.
> 
> Sorry I don't have time to work out a more complete answer, but check
> this out:  http://innig.net/software/ruby/closures-in-ruby.rb it is
> the best exploration of Ruby closures that I've seen.
> 
> 

Paul,

Thanks, that's quite enough :) .  I read through this and I agree its quite
an extensive exploration of 'closure-things'.

I think the answer to my question, then is: define_method cannot define a
method that accepts a block passed implicitly or  using the '&'. 
define_method can define a method that explicitly accepts a 'closure-thing':

define_method('func') do |p1, closure|
  ...
  closure.call ..
  ..
end

used this way:

obj.func(1, lambda( {puts "hello"}))

NOT this way:

obj.func(1) {puts "hello"}  # the way I wanted

Regards,
John



-- 
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