Haskell Language Arbitrary-rank polymorphism with RankNTypes
Introduction
GHC’s type system supports arbitrary-rank explicit universal quantification in types through the use of the Rank2Types and RankNTypes language extensions.
Syntax
- Arbitrary rank quantification is enabled with either the
Rank2TypesorRankNTypeslanguage extension. - With this extension enabled, the
forallkeyword can be used to add higher-rank quantification.
