Editing Monad (functional programming) (section)

=== General interface ===
Every monad needs a specific implementation that meets the monad laws, but other aspects like the relation to other structures or standard idioms within a language are shared by all monads.
As a result, a language or library may provide a general <code>Monad</code> interface with [[function prototype]]s, subtyping relationships, and other general facts.
Besides providing a head-start to development and guaranteeing a new monad inherits features from a supertype (such as functors), checking a monad's design against the interface adds another layer of quality control.{{citation needed|reason=Not sure of a good general source, but both Gentle Intro to Haskell and Real World Haskell discuss type classes|date=November 2018}}