From: Ned Konz <ned@...>
Date: 2002-06-19T03:24:31+09:00
Subject: Re: Debug.rb and exceptions

On Tuesday 18 June 2002 11:00 am, Han Holl wrote:
> Ned Konz wrote:
> >Easy: catch the Errno::EXDEV and instead do a copy followed by a
> >delete of the original.
>
> That is not what I meant at all. What you propose is exactly what
> ftools.rb does. My question: is it impossible to use the debugger
> with software that uses begin - rescue  in Python style ?

Sorry, I misunderstood.

From my reading of debug.rb, it should be possible. If you look at the 
trace_func, you'll see that 'raise' conditions are handled by 
excn_handle(), which does nothing (other than printing a trace to 
stdout) if you don't have a catchpoint set.

Of course, you have to get rid of the default catchpoint on 
StandardError if you want to ignore any of these.

So if you start up the debugger with (say)

cat SystemExit

then it won't break for any exception other than one that's derived 
from SystemExit. You could define your own exception if you wanted to 
really make sure that you didn't catch anything.

Here's an example program (which I called xx.rb):


begin
  puts "before"
  raise StandardError
  puts "after"
rescue StandardError
  puts "caught"
end


And here's my debug session:

$ ruby -rdebug xx.rb
Debug.rb
Emacs support available.

xx.rb:8:end
(rdb:1) cat SystemExit
Set catchpoint SystemExit.
(rdb:1) c
before
xx.rb:4: `StandardError' (StandardError)
caught


-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE