Contents > 8 Defining Custom Design Metrics and Rules > 8.5 Expression Terms > 8.5.1 Constants and Identifiers > Constants Constants

Expression terms frequently contain string and number constants.

A string constant is a sequence of characters, enclosed in single quotes, for example: 'public'. A string constant may contain any sequence of digits (0-9), letters (a-z, A-Z), whitespace, and the underscore (_).

Number constants (integer or floating point) are denoted in the usual way:

Examples of valid numbers are: 2, -1.3, 1e-10.