Remember, scripts are procedural. JMP begins by evaluating the first line and continues through until it ends with the last line. This kind of evaluation makes sense for the parts of your script that always have to be evaluated. This evaluation is unconditional. But some parts of your script should only be evaluated under specific cases. This evaluation is conditional. And your script has to determine when such a case exists and the appropriate action to take when that's true. So when a particular part of your script is conditional, JMP first has to evaluate a condition. The condition can be represented by constants, variables, or the result of calling a function, and the result of testing the condition is a Boolean value (either true or false). There are several functions that return Boolean values: comparison functions like the Less function, logical functions like the Not function, and inquiry functions like the Is List function. JMP responds with a result of to represent true and to represent false. And recall that in general, JMP interprets zero as false and all nonzero numbers as true.
