From: Tim Conner <crofty_james@...>
Date: 2009-04-27T02:40:05+09:00
Subject: Using method missing to create getters and setters

Hi,
I am trying to create a model (BatchExternalBooking) which has the
following methods:
BatchExternalBooking.message_thread_1=
BatchExternalBooking.message_thread_1
BatchExternalBooking.message_thread_2=
BatchExternalBooking.message_thread_2
... etc all the way upto
BatchExternalBooking.message_thread_x=
BatchExternalBooking.message_thread_x

I assume that I need to do this via method_missing because I don't know
how many of these methods I will actually need.

My code currently looks like this:
class BatchExternalBooking
  def method_missing(method_sym, *args)
    if method_sym.to_s =~ /^message_thread_([0-9]*)=?(\w*)?$/
      BatchExternalBooking.instance_eval "attr_accessor
:message_thread_#{$1}"
      self.send("message_thread_#{$1}=", $2)
    else
      super
    end
  end
end

However, this is not working.  See below:
>> b = BatchExternalBooking.new
=> #<BatchExternalBooking:0x3e54040>
>> b.message_thread_1 = 45
=> 45
>> b.message_thread_1
=> ""
The value wasn't actually set but the attr_accessor correctly created
the setter method.  If I try and set the variable again, it works:
>> b.message_thread_1 = 45
=> 45
>> b.message_thread_1 
=> 45

Why isn't the setter working the first time round?

Thanks a lot.
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