From: "David A. Black" <dblack@...>
Date: 2008-10-23T08:34:07+09:00
Subject: Re: neatest way to extend Struct

Hi --

On Thu, 23 Oct 2008, Martin DeMello wrote:

> I want a Structlike class that takes a hash constructor, so I can say
>
> class A < MyStruct.new(*keys); end
>
> a = A.new(:key1 => val1, :key2 => val2)
>
> Is there any way to base this off Struct?

Do you need to use inheritance, as opposed to just instantiating
MyStruct directly? I'm thinking of, for example:

class MyStruct < Struct
   def self.new(*keys)
     s = super
     s.class_eval do
       define_method(:initialize) do |hash|
         hash.each {|k,v| send("#{k}=",v) }
       end
     end
     s
   end
end

A = MyStruct.new(:a,:b)
a = A.new(:a => 1, :b => 2)
p a.b    # 2


David

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