Logical Expressions in WebLord, the Document Assembly Tool
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![]() The Document Assembly Tool |
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Boolean ExpressionsA boolean expression evaluates to either TRUE or FALSE. WebLord's boolean expressions are a combination of one or more simple expressions, connected by boolean operators (AND, OR, XOR). We will look at simple expressions first, then examine the function of boolean operators. Simple ExpressionsA simple expression takes one of two forms, a comparison or define-test:
Examples:
Complex ExpressionsA complex expression consists of two or more simple expressions separated by a boolean operator.
The following reference table may help illustrate the relationship. Tilt your head about 45° to the left, then read one of the left edges, the boolean operator, and the right edge: 'true AND true' is 'TRUE'
Examples:
Negation OperatorBoth simple and complex expressions may be preceded by a keyword "NOT" to change 'true' to 'false' and vice versa. This negation operator may also be written as "!" or "~" Examples:
Evaluation OrderEvaluation order is strictly left-to-right. You must enclose portions of the expression in parentheses (or brackets) to assert full control over the evaluation order. In addition, no short-circuit evaluation will be performed. |
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