From: Ross Bamford <rosco@...>
Date: 2006-01-09T10:53:02+09:00
Subject: Re: Iterator Fu Failing Me

On Mon, 09 Jan 2006 01:09:23 -0000, James Edward Gray II  
<james@grayproductions.net> wrote:

> On Jan 8, 2006, at 6:58 PM, jwesley wrote:
>
>> Perhaps I'm missing the point, but wouldn't the following work: (?)
>>
>>    elements = tokens.map do |token|
>>      val = nil
>>      [ClassA, ClassB, ClassC].find { |kind| val = kind.parse?(token) }
>>      val
>>    end
>
> It works just fine, yes.  Just doesn't feel very Rubyish to me.  <shrugs>
>

Not sure this is more Rubyish (seems a bit line-noisy) but:

	class Parser
	  class << self
	    def parse?(tok)
	      tok.downcase if tok == self.name
	    end
	  end
	end

	class One < Parser; end
	class Two < Parser; end
	class Three < Parser; end

	parsers = [One, Two, Three]
	tokens = ['One','Two','One','siz','Four','Two']

	r = tokens.inject [] do |r,token|
	  r << (parsers.zip([token] * parsers.length).detect { |p,tok| p.parse?  
tok } || [])[0]
	end

	p r

Seems to work. It's *terribly* inefficient though I guess.

-- 
Ross Bamford - rosco@roscopeco.remove.co.uk