From: Phlip <phlip2005@...>
Date: 2009-04-08T23:40:13+09:00
Subject: Re: performing an action only the first time a function called

Don't think of them as "functions". Think of them as "methods", and always put 
them inside classes.

James French wrote:
> Hi,
> 
> Could anyone suggest an elegant way of doing something like:
> 
> $directXSDKBootstrapped = false
> 
> def bootstrapDirectXSDK
>   if !$directXSDKBootstrapped
>     bootstrapBuildToolsDirectory("DirectX/#{DIRECTX_VERSION}")
>     $directXSDKBootstrapped = true
>     $directXSDKBootstrapped.freeze
>   end
> end

class Whatever
  def bootstrapDirectXSDK
    @@directXSDKBootstrapped ||=
      bootstrapBuildToolsDirectory("DirectX/#{DIRECTX_VERSION}")
  end
end

That's teh "proxy pattern" in Ruby...