From: Luc Juggery <luc.juggery@...>
Date: 2006-11-05T00:03:38+09:00
Subject: Add dynamic instance methods in a controller class

Hello All,

I have a problem while developping an application using rails.
In fact, this is more a general question on Ruby methods.
I'd like to add some methods to my controller depending upon some
parameters read from an xml file during initialisation (I hope I am
quite clear :-) )
Below is the code I am using:

----------------
require 'rexml/Document'
include REXML

class MyController < ApplicationController

	def index
                # Xsd is a model (not ActiveRecord that is used to get
values from an XML file
		xsd = Xsd.new("myfile.xsd")
		
		# Get main section
		@main_sections = xsd.get_main_sections	

		# Get item for first section
		@item = xsd.get_items_per_section(@main_sections[0].to_s)

		# Dynamically create method for to retrieve list of fields for each
main sections
                # THIS PART IS NOT WORKING
		@main_sections.each do |section|
			self.instance_eval{ define_method("get_item_for_#{section}") {"toto"}}
		end
	end
end
-----------------


While testing this, I have an error message saying that the
define_method does not exist !!!!
Why is this method not found ???
I am still not sure about the instance_eval, class_eval, define_method
I need to use.
Do you have any clues regarding this problem ?

Thanks a lot,

Luc