I need to build an LDIF in policy basically as a report, as I have been
doing in my toolkit rules in IDM3.5.x and higher.

Core difference is the absence of a nested IF token in 3.01. (I would
love to have the query token, time/convert-time, etc as well, but take
what I got).

So I need to do some parseDN'ing in my rule which is why I want to use
Policy to do it, not some other scripting tools.

I can query for users with my DN syntax attr. I can loop through them.
I cannot test if I got a value returned, since I will get an empty
node for users without the attr.

So I was thinking, replace-all NULL with some known string, then I can
strip the LDIF it generates later to clean it up.

What is a regex for the empty string, such that replace-all <empty
string> with say the literal "Shazam" would work?