PS TEXT FORMAT Reference Manual

Expressions
11387 Tandem Computers Incorporated 5-17
The value that a function returns is of the type defined for that function.
The expressions you supply must also be of the proper types for that
function. This list defines the abbreviations used in the following function
descriptions.
exp represents an expression of a nonspecific type.
b-exp represents a Boolean expression.
i-exp is an integer expression.
n-exp is a numeric expression (either an integer or an integer-and-
fraction combination).
s-exp is a string expression.
exp represents an expression of a nonspecific type.
(B) denotes that the function returns a Boolean value.
(N) denotes that the function returns a numeric value.
(S) denotes that the function returns a string value.
Note Spaces have been added in the following illustration of functions for easier reading. When
you use functions, however, do not add spaces (the exceptions are an expression enclosed
in an indirection escape sequence or a string constant within quotes).
ABS Function The ABS function returns the absolute (unsigned) value of the numeric
expression.
ABS ( n-exp )
An unsigned value is the same as a positive value. (N)