Creates a copy of an existing function such that its results are memoized.
# S3 method for default
addMemoization(fcn, envir=parent.frame(), ...)Returns a function.
A function (or the name of a function) that should be
copied and have memoization added.
The environment from where to look for the function.
Additional arguments for controlling the memoization,
i.e. all arguments of memoizedCall() that are not passed
to do.call().
Henrik Bengtsson
The new function is setup such that the the memoized call is done in the environment of the caller (the parent frame of the function).
If the function returns NULL, that particular function call is
not memoized.
The returned function utilized memoizedCall() internally.