Terms, Concepts, and Placeholders
In syntax summaries, | means “or” and separates possible choices. Usually choices separated by | are mutually exclusive. In other words, you have to pick one and cannot list several.
An argument is something specified inside the parentheses of a JSL operator, function, message, and so forth. Big Class.jmp is the argument in Open("Big Class.jmp").
You can often infer the meaning by the argument’s position. For example, the values 200 and 100 in size(200, 100) are implicit arguments. The first value is always interpreted as the width; the second value is always interpreted as the height. See also named argument.
A Boolean is a yes/no value, something that is on or off, shown ...