NET/MASTER Network Control Language (NCL) Programmer's Guide

2 NCL Summary
106160 Tandem Computers Incorporated 2–1
This section provides an overview of the NonStop NET/MASTER Network Control
Language (NCL). It summarizes the main features and elements of NCL. It briefly
describes every core statement and verb.
Language Features This subsection describes the important general characteristics of NCL:
Context and meaning
Abbreviations
Block structure
Scope
Context and Meaning NCL is a contextual language. The concept of context is that the meaning of a
character or a sequence of characters in an NCL procedure depends on its position
within a statement. A character or a sequence of characters may have one meaning in
one context, but a different meaning in another context.
The phrase current context is used to describe the setting in which one or more
characters become meaningful within an NCL statement.
Context affects the interpretation of:
Keywords
Alphabetic characters
Numeric characters
Nonalphanumeric characters
Interpretation of Keywords
Within a statement, some sequences of alphabetic characters have a predefined
meaning when used in a particular context. These are called keywords. Core
statements and verb statements (hereafter called verbs) are made up, partially or
entirely, of keywords. (Core statements and verbs are discussed later in this section.)
Table 2-1 shows some examples of keywords used in core statements.
Table 2-1. Some Keywords Used in Core Statements
Keyword Used in
EXTPARSE PROCEDURE core statement
FOLD PROCEDURE core statement
LABEL SIGNAL core statement
LIMIT GOSUB and GOTO core statements
MATCH GOSUB and GOTO core statements
OTHERWISE SELECT core statement
SHARE CALL, FUNCTION, and PROCEDURE core statements
SIMPLE PROCEDURE core statement
SMART PROCEDURE core statement
THEN IF core statement