VAX BASIC Reference Manual

This document is the VAX BASIC Reference Manual, Version 3.4, published in February 1990 by Digital Equipment Corporation.

Purpose: The manual serves as a comprehensive reference guide providing detailed information on the syntax and usage of VAX BASIC language elements. It is intended for users who are already familiar with VAX BASIC programming techniques, complementing other manuals in the documentation set (like the VAX BASIC User Manual for tutorials).

Key Information & Updates for Version 3.4: The primary technical change in this version is the addition of support for the Program Design Facility (PDF), implemented via the /DESIGN qualifier for the BASIC DCL command. It also incorporates numerous corrections and clarifications to the Version 3.3 documentation.

Document Structure & Content: The manual is organized into four main chapters and four appendices:

• Chapter 1: Program Elements and Structure Describes the fundamental building blocks of a VAX BASIC program, including program line components (e.g., line numbers, labels, statements, compiler directives), the VAX BASIC character set, various data types (Integer, Floating-Point, Character String, Packed Decimal, Record File Address - RFA), variables (naming conventions, explicit and implicit declaration, arrays, initialization), constants (numeric, string, named, predefined), and different types of expressions (numeric, string, conditional) and their evaluation rules. It also covers program documentation through comments and REM statements.

• Chapter 2: Environment Commands Lists and explains the commands used within the interactive BASIC environment for tasks such as displaying, editing, compiling (COMPILE), loading (LOAD), running (RUN), saving (SAVE), deleting (DELETE, UNSAVE, SCRATCH), and renaming (RENAME) programs. It also covers commands for setting (SET) and showing (SHOW) compiler defaults and system parameters.

• Chapter 3: Compiler Directives Details instructions for the VAX BASIC compiler that influence the compilation process. These directives include conditional compilation (%IF-%THEN-%ELSE-%END %IF), source code inclusion (%INCLUDE), and control over listing file generation (e.g., %LIST, %NOLIST, %CROSS, %NOCROSS, %PAGE, %PRINT, %SBTTL, %TITLE).

• Chapter 4: Statements and Functions This is the core reference section, providing an alphabetical listing of all VAX BASIC statements and functions. Each entry includes its definition, format, syntax rules, and detailed remarks on its operation and any associated restrictions or effects.

Appendices:

• Appendix A: Transporting Programs Between VAX BASIC and BASIC-PLUS-2 Summarizes compatibility issues and functional differences between VAX BASIC and PDP-11 BASIC-PLUS-2.

• Appendix B: ANSI Minimal BASIC Explains how VAX BASIC conforms to the ANSI Minimal BASIC Standard X3.60-1978, detailing extensions and implementation-defined features.

• Appendix C: ASCII Character Codes Provides tables of ASCII character codes and their hexadecimal/decimal values.

• Appendix D: VAX BASIC Keywords Offers a comprehensive list of all reserved and unreserved VAX BASIC keywords.