Negative regular expressions (searching for "i" not inside command)

[Bart Kastermans]

I have a file in which I am searching for the letter "i" (actually
a bit more general than that, arbitrary regular expressions could
occur) as long as it does not occur inside an expression that matches
\\.+?\b (something started by a backslash and including the word that
follows).

More concrete example, I have the string "\sin(i)" and I want to match
the argument, but not the i in \sin.

Can this be achieved by combining the regular expressions?  I do not
know the right terminology involved, therefore my searching on the
Internet has not led to any results.

I can achieve something like this by searching for all i and then
throwing away those i that are inside such expressions.  I am now just
wondering if these two steps can be combined into one.

Best,
Bart
-- 
http://www.bartk.nl/