printing stacktrace

I am trying the following in the irb console

begin         a = 4         a.dfsdfadsf rescue => exp         puts exp.backtrace.join("\n") else         puts "in else" ensure         puts "ensure" end

I am hoping to see a stacktrace of exception complaining about method_missing for Fixnum but instead I get

(eval):3:in `execute' /usr/local/lib/ruby/gems/1.8/gems/interactive_editor-0.0.4/lib/ interactive_editor.rb:33:in `edit' /usr/local/lib/ruby/gems/1.8/gems/interactive_editor-0.0.4/lib/ interactive_editor.rb:42:in `edit' /usr/local/lib/ruby/gems/1.8/gems/interactive_editor-0.0.4/lib/ interactive_editor.rb:80:in `ed' (irb):32:in `irb_binding' /usr/local/lib/ruby/1.8/irb/workspace.rb:52:in `irb_binding' /usr/local/lib/ruby/1.8/irb/workspace.rb:52

Is this a problem with interactive editor or am I not doing it right?

Thanks

I am trying the following in the irb console

begin a = 4 a.dfsdfadsf rescue => exp

Should that be rescue Exception => exp?

Colin