From: Robert Feldt <feldt@...>
Date: 2004-11-01T02:08:09+09:00
Subject: Re: AppConfig, a configuration container class

Robert Feldt wrote:

> martinus wrote:
>
>> Hi! I have written a class that I consider cool enough to share. The
>> problem I tried to solve was that for an application I wrote, I wanted
>> to have all configuration parameters centralized, and seperated from
>> the normal code. At first I used a Hash with parameters names as
>> strings, but this was cumbersome to use. I tried to find a convenient
>> interface to a hierarchy of configuration parameters, and came up with
>> an implementation that automatically defines accessors (actually, I
>> only override method_missing). Have a look at this example:
>>
>> ac = AppConfig.new
>> ac.window.name = "SuperDuper"
>> ac.app.version = "2.1.3"
>> ac.this.is.automatically.created = "blabla"
>>
>> After you have created all of your configuration parameters this way,
>> to prevent typos when using the parameters, the configuration hierarchy
>> can be fixated:
>>
>> ac.fixate
>>
>> After fixating,
>>
>> ac.widnow.name = "UberSuperDuper"
>>
>> generates a NoMethodError, because window was misspelled. Without
>> fixating, this would have created a new setting.
>>
>>  
>>
> It's nice; I've used this for similar situations:
>
> require 'ostruct'
> class RecursiveOpenStruct < OpenStruct
>  def method_missing(method, *args)
>    super || send((method.to_s + "=").intern, RecursiveOpenStruct.new)
>  end
> end
>
> but it doesn't behave exactly the same...
>
I forgot to say: but with freeze as a substitute for your fixate it 
probably behaves close enough.

/R