From: Tony Mobily <merc@...>
Date: 2006-06-26T10:27:35+09:00
Subject: Re: Help with "generating" code

Hi,

***THANK YOU***

I ended up using a solution that was a little different to what I 
originally thought of. However, your input was *vital* for me. The main 
problem was that I was trying to write a class method, where an instance 
method was probably a better idea.
Let me show what I did. I know this is RoR code. However, what I am 
focusing on is Ruby code here.
So, here is what I did.
In the application controller:

class Lookup::AccountNumberController < ApplicationController
[...]

def create
    standard_create :account_number
end
[...]

Then, in the ApplicationController the real magic happens:

class ApplicationController < ActionController::Base
[...]

 def standard_create(name)

    # Fetch the class's pointer called "Name" - THANK YOU Ruby ML!
    klass = self.class::const_get(Inflector.classify(name.to_s))

    # Set @name. For example:
    # @channel = Channel.new(params[:channel]) -  - THANK YOU Ruby ML!
    variable=instance_variable_set('@'+name.to_s,klass.new(params[name]) 
)

    # Try and save the object, blah blah
    if variable.save
      flash[:notice] = "#{name.to_s.humanize} was successfully created."
      redirect_to :action => 'index' if ! parent
    else
      render :action => 'new'
    end
  end
[...]
end

The big issue is that I needed to assign an instance variable, but all I 
had was the name. So, 
instance_variable_set('@'+name.to_s,klass.new(params[name])  ) really 
did the trick. Also, it took me a while to get klass = 
self.class::const_get(Inflector.classify(name.to_s)) (OK, it probably 
sounds totally obvious to you...).

That 
variable=instance_variable_set('@'+name.to_s,klass.new(params[name])  ) 
is a bit of an eye sore. I wonder if there's a better way of "pointing" 
to the instance variable directly...?

Anyway... Ruby truly is beautiful. In my application, I have *LOADS* and 
*LOADS* of tables that are ridicolously similar. Well, this techniques 
literally saves me from cutting&pasting the same code over and over 
again.

I will probably end up writing an article about this (when I am more 
comfortable with what I'm doing).

Bye!

Merc.

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