From: Ara.T.Howard@...
Date: 2004-09-09T07:15:13+09:00
Subject: Re: OK... :) question about hash and array literals

On Thu, 9 Sep 2004, Michael H Buselli wrote:

> Sounds like a new data type to me.  I frequently find myself doing
> things like this:
>
>    @some_data_by_index = Hash.new
>    @some_data_order = Array.new
>
> and then I manage the two variables together for any insertion I make
> into the data:
>
>    @some_data_by_index[value.key] = value
>    @some_data_order.push value
>
> So what if there was an ArrayAndHash?
>
>    @some_data = ArrayAndHash.new(:key)
>    @some_data.push value
>
> Such a thing would need some semantics of both an Array and a Hash, and
> I don't feel like figuring out what they should look like right now.
> Maybe next time I need such a thing I'll think about it more.
>
> Similar things have been discussed on the list before, but I don't know
> if anything became of them.


this doesn't solve the OP's problem - but it might solve the above nicely:

   jib:~ > cat a.rb
   require 'arrayfields'

   a = []
   a.fields = []

   %w(zero one two three).each do |field|
     a[field] = a.size
     p a
     p a.fields
   end


   jib:~ > ruby a.rb
   [0]
   ["zero"]
   [0, 1]
   ["zero", "one"]
   [0, 1, 2]
   ["zero", "one", "two"]
   [0, 1, 2, 3]
   ["zero", "one", "two", "three"]


arrayfields has the semantics that, if the fields have ever been set (even to
an empty set), asigning to an unknown field appends.

so i automatically does

   @some_data_by_index[value.key] = value
   @some_data_order.push value

kind regards.

-a
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