Karl Jones: Created page with "In programming languages, an '''abstract type''' is a type in a nominative type system that cannot be Instance (computer sci..."

2016-09-04T15:06:46Z

Created page with "In programming languages, an '''abstract type''' is a type in a nominative type system that cannot be Instance (computer sci..."

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In [[Programming language|programming languages]], an '''abstract type''' is a type in a [[Nominal type system|nominative type system]] that cannot be [[Instance (computer science)|instantiated]] directly.

Abstract types are also known as existential types.

== Description ==

An abstract type may provide no implementation, or an incomplete implementation.

Often, abstract types will have one or more implementations provided separately, for example, in the form of concrete subclasses that can be instantiated. It may include abstract methods or abstract properties that are shared by its subtypes.

The [[Object-oriented programming|object oriented]] form of abstract types are known as abstract base classes or simply abstract classes.

In some languages, abstract types with no implementation are known as [[Protocol (object-oriented programming)|protocols]], interfaces, signatures, class types.

Other names for language features that are (or may be) used to implement abstract types include traits, [[Mixin|mixins]], flavors, roles, or type classes.

A type that is not abstract is called a concrete type (or concrete class).

== See also ==

* [[Class (computer programming)]]

== External links ==

* [https://en.wikipedia.org/wiki/Abstract_type Abstract type] @ Wikipedia.org

[[Category:Computer programming]]
[[Category:Computer science]]
[[Category:Computing]]

Abstract type - Revision history

Karl Jones: Created page with "In programming languages, an '''abstract type''' is a type in a nominative type system that cannot be Instance (computer sci..."