Compaq AA-PWCBD-TE manual Expressions, Cont. Dectpu Operators, Operator Precedence

Lexical Elements of the DEC Text Processing Utility Language 4.7 Operators

Table 4–5 (Cont.) DECTPU Operators

Type Symbol Description

+Pattern concatenation

&Pattern linkage

Logical	AND	Boolean AND
	NOT	Boolean NOT
	OR	Boolean OR
	XOR	Boolean exclusive OR

You can use the + operator to concatenate strings. You can also use the relational operators to compare a string with a string, a marker with a marker, or a range with a range.

The precedence of the operators in an expression determines the order in which the operands are evaluated. Table 4–6 lists the order of precedence for DECTPU operators. Operators of equal precedence are listed on the same line.

Table 4–6 Operator Precedence

Operator	Precedence
unary +,unary –	Highest
NOT
*, /, AND
@, &, +, –, , OR, XOR
=, <>, <, <=, >, >=
:=	Lowest

Expressions enclosed in parentheses are evaluated first. You must use parentheses for correct evaluation of an expression that combines relational operators.

You can use parentheses in an expression to force a particular order for combining operands. For example:

Expression					Result
8	*	5	/	2 - 4	16
8	*	5	/	(2 - 4)	-20

4.8 Expressions

An expression can be a constant, a variable, a procedure, or a combination of these separated by operators. You can use expressions in a DECTPU procedure where an identifier or constant is required. Expressions are frequently used within DECTPU conditional language statements.

The data types of all elements of a DECTPU expression must be the same. The following are exceptions to this rule:

•You can mix keywords, strings, and pattern variables in expressions used to create patterns.

4–8Lexical Elements of the DEC Text Processing Utility Language