NET/MASTER Network Control Language (NCL) Reference Manual

Lexical Elements of NCL

Compiler Operation

106126 Tandem Computers Incorporated 8–9

Some examples of using parentheses are shown next:

Example Use of Parentheses

&z = &a * (&b + &c) Alters the order of evaluation in an expression.

&z=(&a*(&d**2)*&b)+&c Delimits terms in an expression to clarify the code.

&z=(&a||&b)(&c,xyz) Delimits an expression that resolves to the name of a local

or external function.

call proc1(a,b,c) Delimits parameters in a procedure call.

&a = func1(1,2,3) Delimits parameters in a function call.

msgread vars=(&a,&b,&c) Delimits items in a list.

signal (label) Delimits a keyword in a statement.

Colon

The colon (:) is used to delimit a label. See “Labels,” later in this section, for more

information.

Semicolon

The semicolon (;) is used to explicitly delimit the end of a statement, as in the

following example:

CMD SHOW USERS;SAY F(1,2,3);

Including the semicolon at the end of a line is optional. See “Terminating and

Continuing a Statement,” later in this section, for more information.

Comments The compiler does not regard a comment as a lexical element. Logically, the compiler

replaces the comment with a blank, which is then a lexical element delimiter.

(Depending on the context, this blank may be a blank operator. This is a special use of

the blank and is discussed in Section 10, “Expressions and Operators.”)

For example, the compiler regards the comment in the following line of code as a

blank:

token1/* This comment is between two tokens */token2

The compiler replaces the comment by a blank to produce the following output:

token1 token2

In this way, comments are effectively ignored by the compilation process.

A comment that spans several source lines causes any compiler control statements in

those source lines to be ignored. The compiler control statements are effectively