From: Greg Brondo <greg@...>
Date: 2004-04-01T03:19:21+09:00
Subject: Re: script loading question

gabriele renzi wrote:

> il Wed, 31 Mar 2004 17:24:54 GMT, Greg Brondo <greg@brondo.com> ha
> scritto::
> 
>>I like working in the style of Java (one class per file) for some projects
>>and I've emulated it for an email/webagent app.  What I'm wondering is if
>>there is a *better* or *builtin* way to do this.  Here is my code:
>>
>>def loadAgents(path)
>>    Dir[path + "*Agent.rb"].each { |agent|
>>        agent = File.basename(agent)
>>        if agent =~ /^((\w+)Agent)\.rb/
>>            require $1
>>            $agentFactory[$2.downcase] = $1
>>        end
>>    }
>>end
> 
> I suppose this is reasonable, even if I'd simplify it using an agent/
> directory, and I would it like this:
> 
> def loadAgents
>  Dir['Agents/*.rb'].each do |agent|
> load agent
> end
> 
> def agent_create(name)
>  Object::const_get(name).new
> end
> 
> 
> or at least I'd use a constant
> AgentFactory instead of an ugly dollar-var.
> 
> 
> 
>>I initialize '$agentFactory' to '{}' and add 'lib/' to $: before calling
>>loadAgents().  Then I can 'object = agentFactory[request].new()'.  Also I
>>can add agents just by writing the class in a new agent file in lib and
>>restarting.
>>
>>I guess another question would be how can I reload 'lib/' without
>>restarting?  Does 'load' replace class definitions (it seems require is a
>>'one time thing')?
> 
> yes, require is a one time thing, and load works as expected:
>>> load 'agen.rb'
> => true
>>> Agent.new
> => #<Agent:0x27f6bc0 @a=1>
>>> class Agent
>>>  def initialize
>>>   @b=2
>>>  end
>>> end
> => nil
>>> Agent.new
> => #<Agent:0x27dbe60 @b=2>
>>> load 'agen.rb'
> => true
>>> Agent.new
> => #<Agent:0x27f68d8 @a=1>

Woo hoo!  thanks much.  I could not find the info about const_get(name). 
Works like a champ!