From: Yohanes Santoso <ysantoso-rubytalk@...>
Date: 2004-11-03T13:20:28+09:00
Subject: Re: Programmatically and dynamically catching exceptions

Logan Capaldo <logancapaldo@gmail.com> writes:

> Allright here was my idea which seems to have been shattered by the
> realities of Ruby.
>
> I was thinking of a class called Try. You would do something like
>
> class Try
> ...
> end
>
> tryblock = Try.new { #This block would normally be wrapped in a begin...rescue
>                            }
>
> tryblock.add_exhandler(:SomeException) { |ex| some_code }
>
> tryblock.execute #or possibly tryblock.call ?
>
> Basically the idea was going to be you could subclass Try and provide
> default sensible handling of your Exceptions (if you were writing a
> library for instance) . Users could then then wrap it in a
> begin...rescue block to catch other exceptions or use add_exhandler to
> overide the default handler. (Possibly provide a way to get the old
> handler and and use it in the new).
>
> my idea was going to be that I could do something like
>

class Try
  def execute 
    begin
      user_proc.call(*user_proc_args)
    rescue Error => e
      elt = (exhandlers.select{|obj| e.class == obj.exception_class})[0]
      if elt
        elt.exception_handler.call(e)
      else
        raise e
      end
    end
  end
end


YS.