TOPS-20 PASCAL Primer Sep83

This document, the "TOPS-20 PASCAL Primer" (AA-L314A-TM), published in September 1983, serves as an introductory guide for programmers new to the TOPS-20 PASCAL language (PASCAL V1.0) on the TOPS-20 operating system (V5.1, V4.1). It assumes prior experience in a high-level language or an introductory programming course, along with familiarity with TOPS-20 basics and text editors, but no prior PASCAL knowledge.

The primer introduces a subset of PASCAL-20, which is an extended implementation of the ISO standard PASCAL, incorporating features like an exponentiation operator and a double-precision real data type. For complete reference information, it directs users to the "TOPS-20 PASCAL Language Manual."

The document is structured into seven chapters, intended for sequential reading, covering the following key topics:

• Chapter 1: Introduction – Explains the structure of a PASCAL program and the steps involved in program development (creating, compiling, loading, executing) on the TOPS-20 system.
• Chapter 2: Data Concepts – Describes PASCAL's data and data types, including scalar (INTEGER, REAL, BOOLEAN, CHAR, user-defined) and structured data types, variables, and expressions.
• Chapter 3: Declarations and Definitions – Details how to define symbolic names, constants, types, and variables.
• Chapter 4: Reading and Writing Data – Covers input/output operations using standard text files (INPUT, OUTPUT) and procedures like READ, READLN, WRITE, and WRITELN, as well as EOF and EOLN functions.
• Chapter 5: Structured Types – Focuses on arrays and records.
• Chapter 6: PASCAL Statements – Explains assignment, compound, repetitive (FOR, REPEAT, WHILE), and conditional (IF-THEN, IF-THEN-ELSE, CASE) statements.
• Chapter 7: Procedures and Functions – Discusses the use of subprograms, local/global variables, and parameters.

Additionally, the document includes appendices listing PASCAL-defined names (reserved words, semireserved words, predeclared identifiers) and the ASCII character set, along with a glossary of terms.