From: dblack@...
Date: 2007-03-01T20:48:18+09:00
Subject: Re: default passed block for method

Hi --

On Thu, 1 Mar 2007, Niko wrote:

>
> Hi all,
>
> I'm trying to define the missing block given in the context of 
> the method to avoid the block_given? test on each iteration for 
> yield call.
>
> def self.list_of_relationships(relations, source)
>   # missing_block_that_yield_would_call = lambda { || true } 
> unless block_given?
>   relations.map do |relation|
>     if yield(peer = relation.send(source))
>       [peer.display_name, peer.id]
>     end
>   end.compact
> end

You would want to do:

   def self.list(relations,source,&block)
     block ||= lambda { true } # no need for empty ||
     relations.map do |relation|
       if block.call(peer = ....

etc.  You'd have to do some benchmarks to find out whether the
slowdown from call is worse than the slowdown from block_given?.


David

-- 
Q. What is THE Ruby book for Rails developers?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black)
    (See what readers are saying!  http://www.rubypal.com/r4rrevs.pdf)
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)