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INTRODUCTION TO THE SYMBOL 211 PROGRAMMING LANGUAGE

IP.com Disclosure Number: IPCOM000127985D
Original Publication Date: 1973-Dec-31
Included in the Prior Art Database: 2005-Sep-14
Document File: 12 page(s) / 35K

Publishing Venue

Software Patent Institute

Related People

Hamilton Richards, Jr.: AUTHOR [+4]

Abstract

Hamilton Richards, Jr. Charles Wright, Jr. October 1973 This paper was presented at the Symposium on the High-Level Language Computer Architecture University of Maryland, College Park, Maryland November 1973

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

INTRODUCTION TO THE SYMBOL 211 PROGRAMMING LANGUAGE

Hamilton Richards, Jr.

Charles Wright, Jr.

October 1973

This paper was presented at the Symposium on the High-Level Language Computer Architecture University of Maryland, College Park, Maryland November 1973

I. INTRODUCTION

The SYMBOL programming language (SPL) is not only an important feature of the SYMBOL 2R Computer System, but also was the starting point for the design of the system. SPL was designed as a general-purpose, higher-level programming language. After the language design was completed, the hard-ware of the SYMBOL computer was then designed to provide a hardware implementation of the language.

This paper is intended primarily to provide a general overview of SPL as context for the com- panion papers (1,3,6). The reader is referred to (5) for a complete d6scription of SPL, to (2) for a discussion of the design decisions involved in the creation of SPL, and to (4) for an overview of the entire SYMBOL project.

As mentioned, SPL is a general-purpose, higher-level programming language, Some of its main characteristics are:

(1) SPL deals with only two types of data values - character string scalars of arbitrary length and lists (called structures) of arbitrary size and shape.

(2) Unlike many general-purpose languages, SPL is free of declarations as to the size and type of variables. Values of variables are free to change in length (and shape as well, in the case of structures) during program execution, according to the demands of the program. SYMBOL operators automatically accommo. date scalar operands of any length.

(3) SPL contains a generally standard set of constructs for the purpose of con-trolling program execution, including conditional statements, transfer state-ments, and procedures.

The various features of SPL will now be illustrated by means of partial SPL programs.

Computer Science Department. Supported under NSF Grant GJ-33097X. 2 Computer Science Department. Supported under NSF Grant GJ-33097X and by the U.S. Atomic Energy Commission under Contract No. W-7405-eng-82.

II. SCALAR VALUES, OPERATORS, AND EXPRESSIONS

Iowa State University Page 1 Dec 31, 1973

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INTRODUCTION TO THE SYMBOL 211 PROGRAMMING LANGUAGE

A scalar value in SPL is simply a string of zero or more characters. There exist, in SPL, twenty- two operators defined on scalar operands and yielding,in all cases, scalar results. The examples in this section are intended to illustrate these operators and to give some idea of the character- processing capabilities of SPL. It is assumed that the use of the assignment operator prior to its treatment in Section TV will be self-explanatory.

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Literal scalars, or constants, are enclosed in vertical bars (It I ") . These vertical bars are optional for literal scalars that conform to the syntax of numbers.

String relational operators yield ei...