ABSTRACT
This chapter introduces the programming related to the kernel of R. By studying pryr package the chapter understands the features of the lower level of R, learn how to define the environments in R and use the function environments, master the management of file system with R, and interpret the new features of R version 3.1. The pryr package is such a tool that helps to understand the execution mechanism of R language. The APIs of the pryr package mainly include functions such as internal implementation utilities, object-oriented (OO) checking utilities, assisted programming functions, code simplification utilities, and so on. The environment is part of the low-level design of R in terms of computer technologies. It is mainly used for the environment loader of R. An environment is a data structure defined by the kernel of R and comprised of a series of the hierarchical frames.
