Nametype definitions associate a name with a type expression, meaning that `.' and `( , , )' operate on it as type constructors rather than value expressions. The type name may not take parameters.
For example,
nametype Values = {0..199}
nametype Ranges = Values . Values
has the same effect as
Values = {0..199}
Ranges = { x.y | x<-Values, y<-Values }
Note that outside of the `top-level' of a nametype (or datatype)
definition, the expression `Values . Values' has the entirely
different meaning of two copies of the set Values joined by the
infix dot.
Similarly the expression `(Values,Values)' means the cartesian
product of Values for the construction of a name- or data-type,
but a pair of two sets in all other contexts.
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