// create a circle class. Note that a class is, like a function, a value, and // therefore should be assigned to a variable. So "circle" is not the name of // the class, but the name of the variable used to store the class circle = class public radius = (0+ to inf); auto perimeter = () -> 2 * pi * parent.radius; auto area = () -> pi * (parent.radius)^2; end person = class public gender = "M" in {"F", "M"}; public age = 1 in (1 : 150); public firstname = "Mark" in ~/[A-Za-z][A-Za-z]*/; public lastname = "Brown" in ~/[A-Za-z][A-Za-z]*/; end