3.0. REXX Built-in Functions This chapter describes the REXX library of built-in functions. It is divided into three parts: · First a general introduction to built-in functions, pointing out concepts, pitfalls, parameter conventions, peculiarities, and possible system dependencies. · Then there is the reference section, which describes in detail each function in the built-in library. · At the end, there is documentation that describes where and how Regina differs from standard REXX, as described in the two other sections. It also lists Regina’s extensions to the built-in library. It is recommended that you read the first part on first on first reading of this documentation, and that you use the second part as reference. The third part is only relevant if you are going to use Regina.