PL/I Language Programmer's Guide

Digital Research, 1982. — 281 p.The PL/I system is a complete software package for both applications and system programming. PL/I runs under the Digital Research single-user operating systems, CP/M or CP/M-86. PL/I runs in a multiuser environment, under MP/M II, or MPIM-86. This manual assumes you are familiar with your operating system and minimizes references to it.PL/I is formally based on the Subset G language defined by the ANSI PL/I Standardization Committee X3Jl. Subset G contains all the necessary application programming constructs of full PL/I, and discards seldom-used or redundant forms. The resulting language encourages good programming practices while simplifying the compilation task.The PL/I Language Programming Guide is divided into three parts. The first part, Sections 1 through 6, presents a brief introduction to the PL/I language, with emphasis on block structure, data types, and its various executable statements. Section 5 gives guidelines for developing a readable programming style. Section 6 explains the operation of the system as a whole, and introduces you to the mechanics of compiling, linking, and executing programs.The second part, Sections 7 through 16, contains detailed sample programs that illustrate the useful facilities of the language, including Input/Output processing, string and list processing, scientific computation, and business applications. Each section presents general concepts, and then a detailed discussion of one or more example programs to illustrate the concepts.The third part, Sections 17 through 20, presents advanced programming topics, such as the internal representation of data, conventions for interfacing assembly language programs with PL/I modules, making direct operating system calls, and writing PL/I programs that use overlays.The best way to learn any programming language is to study working examples. To learn PL/I, you should study these example programs along with the associated text, and cross-check the material with the PLII Language Reference Manual when necessary. Once you understand the operation of a particular program, you can modify the program to enhance its operation and further your experience with the language.