Programming language pl/1

TL;DR: This chapter focuses on the programming language PL/1, which has drawn features from Fortran, Algol, Cobol, and several other languages.

Abstract: This chapter focuses on the programming language PL/1, which has drawn features from Fortran, Algol, Cobol, and several other languages. Most of the concepts in PL/1 are implementations or extensions of present ideas. On the elementary level, PL/1 is no more difficult to understand than Fortran. The chapter discusses the advanced features of PL/1 and the way in which they are implemented. In PL/1, the compiler automatically produces code to process numbers, arrays, strings of characters, and so on. Some of this code is in-line and some of it simply produces a call to a subroutine. The number of features that can be included in a compiler is limited only by the judgement and the manpower available to the compiler writers. There are many features that can be included, which would only confuse the prospective user. On the other hand, there are many features where external specification is very simple but where implementation is complex. PL/1 users enter the standard Fortran 48 character set or a 60 character set. PL/1 is a more difficult language than Fortran or Algol largely because it allows a much wider range of expression.