Recursive Partitioning and Regression Trees (rpart)
Recursive partitioning for classification, regression and survival trees. An implementation of most of the functionality of the 1984 book by Breiman, Friedman, Olshen and Stone.

Bindings to the ‘CommonMark’ Reference Implementation (commonmark)
The ‘CommonMark’ spec is a rationalized version of Markdown syntax. This package converts markdown text to various formats including a parse tree in XML format.

Improved Communication to Users with Respect to Problems in Function Arguments (ArgumentCheck)
The typical process of checking arguments in functions is iterative. In this process, an error may be returned and the user may fix it only to receive another error on a different argument. ‘ArgumentCheck’ facilitates a more helpful way to perform argument checks allowing the programmer to run all of the checks and then return all of the errors and warnings in a single message.