From: Chris White <cwprogram@...>
Date: 2011-07-30T11:12:49+09:00
Subject: Re: Dynamic creation of variables


> puts elements[0].name #=> "hydrogen"
> puts @H.name #=> "hydrogen"
>
> But i would prefer it if the elements were loaded up as normal variables
> without the '@' in front.

I would recommend making a module, then setting module constants for your element symbols to be mapped to objects. Here is a sample I threw together:

module Chemistry
    class Element
        attr_reader :name
        attr_reader :mass
        attr_reader :symbol

        def initialize(name,mass,symbol)
            @name = name
            @mass = mass
            @symbol = symbol
        end
    end
end

elements = [
    Chemistry::Element.new("hydrogen", 1.0079, "H"),
    Chemistry::Element.new("lithium", 6.941, "Li")
]

elements.each do |element|
    Chemistry.const_set(element.symbol, element)
end

include Chemistry
puts Li.name

Please note the include Chemistry which makes the "Li.name" access possible. This has the advantage of being able to use these constants in other scripts where someone might want to use the H constant for a different purpose, then they can access it like this:

Chemistry::Li.name

Regards,
Chris White
Twitter: @cwgem