From: Trans <transfire@...>
Date: 2009-01-12T04:13:29+09:00
Subject: Re: Binding.of_caller examples don't work.



On Jan 11, 1:11 pm, "Pit Capitain" <pit.capit...@gmail.com> wrote:
> 2009/1/11 Phlip <phlip2...@gmail.com>:
>
> > Trans wrote:
> >> Binding.of_caller is no longer possible.
>
> > Is a workaround available?
>
> It seems that the original idea of Florian Groß is still valid. Here's
> a version working for my Ruby 1.8.6 on Windows:
>
>   ##
>   #  Re-implementation of Binding.of_caller for Ruby 1.8.6
>   #  (C) 2009 Pit Capitain
>   #  Original idea and implementation by Florian Gross
>   #
>   def Binding.of_caller
>
>     old_critical = Thread.critical
>     Thread.critical = true
>
>     restart_cc = result = error = nil
>
>     expected_events = %w"line c-call c-return return return"
>     tracer = lambda do |event, file, line, id, binding, classname|
>       if expected_events.empty?
>         set_trace_func(nil)
>         result = binding
>         restart_cc.call
>       elsif event != expected_events.shift
>         set_trace_func(nil)
>         error =
>           "Binding.of_caller used in non-method context" +
>           " or trailing statements of method using it aren't in the block."
>         restart_cc.call
>       end
>     end
>
>     callcc { |cc| restart_cc = cc }
>
>     if result
>       yield(result)
>     elsif error
>       raise(ArgumentError, error)
>     else
>       set_trace_func(tracer)
>     end
>
>   ensure
>     Thread.critical = old_critical
>   end

Cool. But word or warning to Doug, I would not recommend using
#set_trace_func in a production application. It can slow things down
considerably.

T.