From: Sean O'Halpin <sean.ohalpin@...>
Date: 2005-09-29T00:53:31+09:00
Subject: Re: Dynamically generating classes?

On 9/28/05, Jonathan Yurek <jyurek@thoughtbot.com> wrote:
> [snip]
>
>  > #<MyEx1: {code: 2, message: Whoops!}>
>
> Isn't that wrong, though? You instantiated MyExt1, but your code and
> message are displaying what MyExt2 should be.
>
> -- Jon
>
>

Hey - you're right! It's the for vs each scoping again! Ouch!

This works as expected:

ERROR_CODES = {
 :MyEx1 => {'code' => 1, 'message' => "Oops!"},
 :MyEx2 => {'code' => 2, 'message' => "Whoops!"},
 }

ERROR_CODES.each do |k,v|
  Object.const_set(k, Class.new(Exception) {
   define_method :to_s do
     "{code: #{v['code']}, message: #{v['message']}}"
   end
  })
end

p MyEx1.new
p MyEx2.new

__END__
#<MyEx1: {code: 1, message: Oops!}>
#<MyEx2: {code: 2, message: Whoops!}>

But best not to do it this way - see Devin Mullins' post for a better way.

Sean