A LearnerRegr for a regression tree implemented in rpart::rpart() in package rpart. Parameter xval is set to 0 in order to save some computation time.
rpart::rpart()
xval
LearnerRegrRpart
R6::R6Class inheriting from LearnerRegr.
Breiman, L. (1984). Classification and Regression Trees. New York: Routledge. https://doi.org/10.1201/9781315139470