Built-in type constructors

Unison has the following built-in type constructors.

• (->) is the constructor of function types. A type X -> Y is the type of functions from X to Y.
• Tuple is the constructor of tuple types. See tuple types for details on tuples.
• List is the constructor of list types. A type List T is the type of arbitrary-length sequences of values of type T. The type [T] is an alias for List T.
• Request is the constructor of requests for abilities. A type Request A T is the type of values received by ability handlers for the ability A where current continuation requires a value of type T.