The SNOBOL3 Programming Language

In recent years a number of high-level programming languages have been developed to extend the usefulness of the computer in dealing with primarily nonnumerical problems. The most widely used languages have been IPL, 1 LISP,2 and COMIT. 3 In 1902 SNOBOL4 was developed for problems involving the manipulation of character strings. The basic operations of SNOBOL permit the formation, examination, and rearrangement of strings. SNOBOL3 is a generalization and extension of SNOBOL. New features include string-valued functions and inputoutput facilities integrated into the string structure of the language. There are two types of functions: primitive functions that are included in the system and defined functions that are defined by the programmer in the SNOBOL3 language. This paper is a description of SNOBOL3 as a programming language. Emphasis is placed on the language as distinct from its implementation. In order to provide information for the potential programmer, however, some references to the implementation are necessary. There are several implementations of SNOBOL3 which differ in detail, particularly with regard to input-output. The implementation for the IBM 7094 computer operating under the BE-SYS-7 monitor is the basis for this paper. 895