[R] finding out if a method exists

[Therneau, Terry M., Ph.D.]

I'm thinking of adding a new "cmatrix" function/method to the survival package but before 
I do I'd like to find out if any other packages already use this function name.   The 
obvious method is to look at the NAMESPACE file for each package in CRAN and read the 
export list.

This is the kind of task for which someone, somewhere will have written routines.  I just 
don't know who or where.

Any hints?

Terry T.