semigroupoids

A semigroupoid is a Category without id. This package provides a range of id-free versions of type classes, as well as some supporting functions and data types.

Field Guide

The diagram below describes the relationships between the type classes defined in this package, and those from base (with some from contravariant as well). Thick-bordered nodes correspond to type classes defined in this package; thin-bordered ones are from elsewhere. Solid edges represent subclass relationships that actually exist; dashed edges are those which should exist in theory.

We also provide the following table. This is structured in superclass order - thus, for any type class T, all superclasses of T will be listed before T in the table.

Name	Location	Superclass of	Ideally superclass of
Functor	base	Alt, Apply, Traversable
Foldable	base	Traversable, Foldable1
Bifunctor	base	Biapply
Contravariant	base	Divise, Decide
Semigroupoid	semigroupoids		Category
Alt	semigroupoids	Plus
Apply	semigroupoids	Bind	Applicative
Traversable	base	Traversable1
Foldable1	semigroupoids	Traversable1
Biapply	semigroupoids
Divise	semigroupoids		Divisible
Decide	semigroupoids	Conclude	Decidable
Category	base	Arrow
Plus	semigroupoids		Alternative
Applicative	base	Alternative, Monad
Bind	semigroupoids		Monad
Traversable1	semigroupoids
Divisible	contravariant
Conclude	semigroupoids		Decidable
Arrow	base
Alternative	base	MonadPlus
Monad	base	MonadPlus
Decidable	contravariant
MonadPlus	base

We omit some type class relationships from this diagram, as they are not relevant for the purposes of this package.

Contact Information

Contributions and bug reports are welcome!

Please feel free to contact me through Github or on the #haskell IRC channel on LiberaChat.

-Edward Kmett