An expression is a set of characters starting with a left bracket ([) and ending with a right bracket (]). Located between the brackets are numbers, parameter values, binary operators, functions, and other expressions. An expression is evaluated to produce a number. An example of an expression is:

[1 + acos[0] – [#3 ** [4.0/2]]]

All expressions on a line are evaluated when the line is read and before anything on the line is executed.

Read the following sections for reference: