From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-09-20T22:47:56+09:00
Subject: Re: Array#index block and rdetect

On Monday 20 September 2004 08:54 am, Robert Klemme wrote:
> In my understanding Enumerable#each_with_index just goes through the
> enumerable and counts an index which can be used for printing or counting
> or whatever.  So I would not change this method.  These indexes are purely
> per enumeration and can change for any number of reasons.

That's an interesting perspective. So you're saying index is just a "helper" 
counter. These being equivalent:

  enumobj.each_with_index {|a,i| ... }

  enumobj.each {|a| i=(i||-1)+1; ... }

Maybe so, although I'd prefer #each_with_counter, in that case. Think of an 
"index" in the back of a book.


A bit of an aside, I've been thinking about synchronizing enumerable objects. 
For the sake of discussion lets say *=* means synchronize. So,

  ([1,2,3]*=*[7,8,9]).each {|a,b| puts "#{a},#{b}" }

  => 1,7
     2,8
     3,9

Then "indexing" can also be done with

  (enumobj*=*(0..enumobj.length-1)).each{|a,i|}

If a method #range is defined, this can be simplified too

  (enumobj*=*enumobj.range).each{|a,i|}

Is there a good way to do this?


T.
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