Nothingconstructor has no fields, it is not a function, it's a constant, that can assume the type
Maybe afor any choice of
Vectorclass defined like so:
Shapeexample once again. Suppose we have facilities for rendering circles and rectangles and we need to render general
Shapes. This can be accomplished with a simple case expression:
case ... ofwe need to provide the object which identity we need to discover and then we provide a series of clauses, each providing a return value to use in the case of the particular constructor.