grep

[Mark nesterovych]

Hi all.

Decided to write BSD licensed grep and provide it to FreeBSD project if
success.
But encountered with a problem, which I can resolve.
I looked through the gnu, OpenBSD sources and posix requirements to this
utility, and can't find a solution. 
Problem is next. System have few utilities [e|f]grep. And have a keys -E
-F and -G which force the certain regexp processing mode.
But I can't find what to do if mode caused by the utility name is
another than mode of a key provided to it.
If an error should be printed and utility should exit. Or may be a key
must be more preferable.

OpenBSD use the latest key provided in alphabetical order.
Gnu's looks for a single key, error if 2 ore more provided.
Posix requirements aks only for one key to be provided.

How to deal with this in right way ?

--
Mark Nesterovych