A Boolean expression is a combination of constant values, variables, operators and functions that, when evaluated, produces a Boolean value (i.e. either "true" or "false").  An example of a Boolean expression is as follows:

 

x > 1

 

This expression represents a single test on a given number, x.  It yields true for all values of x greater than 1 and false for all values of x less than or equal to 1.

 

A more complex example, involving two tests, is shown below:

 

x ≥ 1 AND x ≤ 10

 

This expression, which makes use of the Boolean "AND" operator, yields true only if the value of x is in the range 1 to 10 inclusive.

 

Absyntax uses Boolean expressions in a variety of contexts as the basis for tests.  You can create such expressions in the Absyntax Editor using the Filter Builder.