From: Robert Klemme <shortcutter@...>
Date: 2009-11-13T02:00:06+09:00
Subject: Re: Enumerable#find_yield, useful shortcut? better name?

On 12.11.2009 17:41, Aaron Patterson wrote:
> On Fri, Nov 13, 2009 at 01:07:41AM +0900, Intransition wrote:
>> This method has long been suggested to me as #map_detect. At first I
>> wasn't sure of it's usefulness. But now I think it's okay. (Your
>> thoughts?). In any case, the name has to go. Currently I'm thinking
>> #find_yield. Any better suggestions?
> 
> I would call the method "unnecessary".  Especially since we already have
> a built in syntax which is more concise:
> 
>   [1,2,3].find { |_| false }      # => nil
>   [1,2,3].find { |_| false } || 1 # => 1

I disagree.  The difference between TMISFAN (the method in search for a 
name) and your solution is that TMISFAN returns the result of the block 
evaluation and not the element contained in the collection.

I don't have frequent use for this but it occurred just a few days ago. 
  This is what I did then - roughly:

x = nil
enum.any? {|e| e > 10 and x = e * 2}

This is dummy code of course, I don't have the concrete example handy. 
The main point is that #any? will short circuit (like #find) and the 
special value is reserved via the variable.

How about #find_map?  This expresses what happens, first a search and 
then a mapping of the value - sort of.

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/