package preface

Building a Preface_specs.Invariant

Using the minimal definition

Build a Preface_specs.INVARIANT using Preface_specs.Invariant.WITH_INVMAP.

Standard method, using the minimal definition of a contravariant functor to derive its full API.

From other abstraction

From a Functor

Specialize a Preface_specs.FUNCTOR into a Preface_specs.INVARIANT.

From a Contravariant

Specialize a Preface_specs.CONTRAVARIANT into a Preface_specs.INVARIANT.