From: dblack@...
Date: 2006-01-05T11:13:11+09:00
Subject: Re: Default block parameter?

Hi --

On Thu, 5 Jan 2006, Mark J.Reed wrote:

> Okay, this is probably a dumb question, but how do I declare an
> optional block parameter with a default value?
>
> I tried several variations on this basic theme:
>
>        def meth(&block = lambda { |i| ... })
>        ...
>        end
>
> But I keep getting syntax errors.  Help?

The &block thing is a special dispensation from Ruby, letting you grab
the block but not serving as a normal argument.  The way I've always
seen this done is:

   def meth(&block)
     block ||= lambda { ... }
     ...
   end

I don't think there's a way to do it inside the arglist.


David

-- 
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!
http://www.manning.com/books/black