Regexp problem

From: chatiman (chatiman_at_free.fr)
Date: 02/28/04 

Date: Sat, 28 Feb 2004 18:32:02 +0100

Hello,

I'd like to match a line which does not begin with a given words and match a
given regexp.
eg:
lines which contains "bar" but does not begin with "foo"

I tried the following regexp but this doesn't work:
/^(?<!foo).*bar/

Any ideas to do that in 1 regexp?