Expressions

Expressions combine one or more of the following nu/TPU items into a statement to be evaluated: constant, keyword, procedure, built-in function, keyword, constant, procedure, variable, string, or integer. Expressions can be one of four types: Arithmetic, Boolean, Pattern, or Relational. Expressions are not required to have an assignment. Within procedures, expressions can be used in place of constants or identifiers. The elements of an expression must be the same type of data, except strings and patterns can be intermixed in pattern expressions, or when using the equal (=) or not equal (<>) relational operators. Strings and integers can be mixed for string replication operations.

Expressions normally evaluate to the same type as their elements. Relational and Boolean expressions always give an integer result. Pattern expressions always give pattern results. For Boolean evaluations, even numbers evaluate to false and odd numbers evaluate to true.

Lastly, expressions are evaluated first by operator precedence then in left to right order.