From: Robert Dober <robert.dober@...>
Date: 2007-01-12T18:56:08+09:00
Subject: RCR Opinion Poll

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Hi all

there is one thing concerning enumerations I really would like to file a CR
about. But I guess it is necessary to open my ears and listen to your POVs
before doing so. I believe that similar things are already done in lots of
extension libraries like e.g. facet.

The most concerning thing is that there will probably be no consensus about
the magic dot notation, I know this has been discussed before.

Here we go


Potential RCR, opinions wanted
==============================


The following is a very common pattern.

    an_enum.map{ |ele| ele.a_method }

I believe that it is sufficiently common to be generalized.

There are two idioms I would like to see

   an_enum.apply_to_all :a_method
and
   an_enum.apply_to_all.a_method

the mutating version should also be available

   an_enum.apply_to_all! :a_method
and
   an_enum.apply_to_all!.a_method

Reference Implementation:

module Enumerable

    def apply_to_all(method = nil)
        return ApplicationProxy.new( self, :modify => false ) unless method
        map { |ele| ele.send method }
    end #def apply_to_all(method = nil)

    def apply_to_all!(method = nil)
        return ApplicationProxy.new( self, :modify => true ) unless method
        map! { |ele| ele.send method }
    end #def apply_to_all(method = nil)

    class ApplicationProxy
        def initialize( enumerable, modifications = {} )
            @modify = modifications[ :modify ]
            @target = enumerable
        end
        def method_missing name, *args, &blk
            @modify ?
                @target.map!{ |ele| ele.send( name, *args, &blk ) } :
                @target.map{ |ele| ele.send( name, *args, &blk ) }
        end
    end #class ApplicationProxy
end #class Enumeration
==================================================

Ty in advance

Robert

-- 
"The best way to predict the future is to invent it."
- Alan Kay

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