Policy Server Guides › Policy Server Configuration Guide › User Directories › Named Expressions › Define Named Expressions › How to Use the Expression Editor

How to Use the Expression Editor

You can use the expression editor to:

• Look up SiteMinder functions and operators and user-defined named expressions
• Build a Boolean expression

Note: If you prefer to enter an expression directly, you can click Cancel and return to the Create Expression: Name pane, where you can type the expression in the Expression field on the Add Named Expression group box.

Building a Boolean expression in the expression editor is a two-part process. The parts of the process can be repeated in any order:

1. Create conditions
2. Edit the expression

In the first part of the process, you can create conditions and add them to the Infix Notation group box. A condition is a simple Boolean expression that consists of a single SiteMinder function or operation. In the editor, a function can have up to three parameters and has the following format:

FUNCTION_NAME(parameter_1[, parameter_2][, parameter_3])

An operation requires two operands and has the following format:

left_operand operator right_operand

Since conditions are Boolean expressions, they result in a Boolean value. If a condition contains a function or operation that results in a string, it will be converted to a Boolean value. Specifically, the following string values are converted to TRUE: "TRUE", "true", "YES", and "yes". All other string values are converted to FALSE.

Likewise, if a condition contains a function or operation that results in a number, it will be converted to a Boolean value. All non-zero numbers are converted to TRUE, while zero is converted to FALSE.

Each condition is displayed on a separate line in the field on the Infix Notation group box and is connected to the condition in the line above by one or two Boolean operators, as follows:

condition_1
AND | OR | XOR [NOT] condition_2

In the second part of the process, you can edit the expression by modifying and deleting the conditions, changing the parentheses that group the conditions, and by changing the Boolean operators that connect the conditions in the field on the Infix Notation group box. For example, you can change how the conditions are grouped:

(condition_1
AND condition_2)
OR NOT condition_3

can become

condition_1
AND (condition_2
OR NOT condition_3)