Determines whether a function name looks like an S3 generic function
leadingS3generic(name,
env, ...)name of function
environment to search for additional generics
ignored here
If a matching generic found returns a list with a single component:
a character vector containing generic name and object name.
If no matching generic functions are found, returns an empty list.
This function is one of the default parsers, but exposed as
possibly of more general interest. Given a function name of the form
x.y.z it looks for the generic function x applying to objects of class
y.z and also for generic function x.y applying to objects of class z.
Assumes that the first name which matches any known
generics is the target generic function, so if both x and x.y
are generic functions, will assume generic x applying to objects
of class y.z