Boolean Is Less Than '<', '<='

The Boolean operator Is Less Than compares two operands and returns TRUE (-1) if the first value is less than the second value, or returns FALSE (0), otherwise. Is Less Than can be used in both variable and constant expressions. Example:

X := Y < Z

The above example compares the value of Y with the value of Z and sets X to either: TRUE (-1) if Y is less than the value of Z, or FALSE (0) if Y is equal to or greater than the value of Z.

This operator is often used in conditional expressions, such as in the following example.

IF (Y < 32)

Here, the Is Less Than operator returns TRUE if Y is less than 32.

Is Less Than has an assignment form, <=, that uses the variable to its left as both the first operand and the result destination. For example,

X <= Y     'Short form of X := X < Y 

Here, X is compared with Y, and if X is less than Y, X is set to TRUE (-1), otherwise X is set to FALSE (0). The assignment form of Is Less Than may also be used within expressions for intermediate results; see Intermediate Assignments.