[R] Writing custom functions for rpart

[hadley wickham]

Hi everyone,

Does anyone has experience with (or documentation for) writing custom
methods with rpart? The documentation hints: "Alternatively, 'method'
can be a list of functions 'init', 'split' and 'eval'", but doesn't
provide any details as to what those methods should do or what
arguments they should take etc.

I've tried looking at the package source (and the source for the S
code it came from) but I can't follow what's going on in C vs R, and
as the default methods are coded in a different way, there are no
examples to follow.

Thanks,

Hadley