dpANS DIBOL

This document is the dpANS DIBOL Language Reference Manual, published in March 1988 by Digital Equipment Corporation.

Purpose: It serves as a comprehensive reference for all aspects of the dpANS (Digital Proposed American National Standard) DIBOL Programming Language. A key point highlighted is that it does not include information specific to particular operating systems or their unique effects on DIBOL, focusing solely on the language standard itself.

Audience: The manual is intended for both programmers new to DIBOL (who have experience with other high-level languages) and experienced DIBOL programmers.

Applicability: The DIBOL version described is applicable to VAX/VMS Version 5.0 or later, RSTS/E DIBOL Version 9.5 or later, and all products containing dpANS DIBOL.

Content Overview: The manual is organized into several key chapters and appendices:

• Language Elements (Chapter 1): Covers the fundamental components of DIBOL, including its character set, different statement types (Compiler Directives, Data Specification, Data Manipulation, Control, Intertask Communications, Input/Output), program structure, statement line syntax, labels, literals, and expressions.
• Data Division (Chapter 2): Details statements used for defining data areas and variables, specifically RECORD, COMMON, SUBROUTINE statements, and field definitions.
• Procedure Division (Chapter 3): Focuses on statements that control program execution and data processing. This includes value assignment, data manipulation (e.g., CLEAR, DECR, INCR, LOCASE, UPCASE), control flow (e.g., CALL, DO-UNTIL, FOR, GOTO, IF-THEN-ELSE, REPEAT, WHILE, EXIT, EXITLOOP, RETURN, STOP, USING), intertask communications (LPQUE, RECV, SEND), and various input/output operations (e.g., ACCEPT, CLOSE, DELETE, DISPLAY, FORMS, OPEN, READ, READS, STORE, UNLOCK, WRITE, WRITES). It also explains array subscripting and substrings.
• Compiler Directives (Chapter 4): Describes non-executable instructions to the DIBOL compiler, such as .END, .IFDEF, .IFNDEF, .INCLUDE, .LIST, .MAIN, .NOLIST, .PAGE, .PROC, .SUBROUTINE, and .TITLE.
• External Subroutines (Chapter 5): Provides reference information and examples for a set of external subroutines like ASCII, DATE, DECML, DELET, ERROR, FATAL, FILEC, FLAGS, INSTR, MONEY, RENAM, RSTAT, SIZE, TIME, and TTSTS.
• Appendices & Glossary: Includes an appendix detailing the dpANS DIBOL Character Set (Appendix A) and comprehensive information on Error Handling, listing error numbers and mnemonics (Appendix B). A glossary defines key terms and phrases used throughout the manual.

Manual Format: Each topic within the manual typically follows a consistent structure for easy information retrieval, including sections for "Function," "Format," "Rules," "Run-Time Error Conditions," and "Examples."