Editing Polymorphism (computer science) (section)

{{Short description|Using one interface or symbol with regards to multiple different types}}
{{Distinguish|Polymorphic code}}
{{Polymorphism}}
In [[programming language theory]] and [[type theory]], '''polymorphism''' is the use of one symbol to represent multiple different types.<ref name="Luca">{{Cite journal |last1=Cardelli |first1=Luca |author1-link=Luca Cardelli |last2=Wegner |first2=Peter |author2-link=Peter Wegner (computer scientist)|doi=10.1145/6041.6042 |title=On understanding types, data abstraction, and polymorphism |journal=[[ACM Computing Surveys]] |volume=17 |issue=4 |pages=471–523 |date=December 1985 |url=http://lucacardelli.name/Papers/OnUnderstanding.A4.pdf |citeseerx=10.1.1.117.695 |s2cid=2921816}}: "Polymorphic types are types whose operations are applicable to values of more than one type."</ref>

In [[object-oriented programming]], polymorphism is the provision of one [[Interface (object-oriented programming)|interface]] to entities of different [[data type]]s.<ref>{{cite web |url=http://www.stroustrup.com/glossary.html#Gpolymorphism |last1=Stroustrup |first1=Bjarne |author1-link=Bjarne Stroustrup |title=Bjarne Stroustrup's C++ Glossary |date=February 19, 2007 |quote=polymorphism – providing a single interface to entities of different types.}}</ref>  The concept is borrowed from a principle in [[biology]] where an organism or species can have many different forms or stages.<ref name="Moved">{{cite web |title=Polymorphism |work=The Java Tutorials: Learning the Java Language: Interfaces and Inheritance |publisher=Oracle |url=https://docs.oracle.com/javase/tutorial/java/IandI/polymorphism.html |access-date=2021-09-08}}</ref>

The most commonly recognized major forms of polymorphism are:
* ''[[Ad hoc polymorphism]]'': defines a common interface for an arbitrary set of individually specified types.
* ''[[Parametric polymorphism]]'': not specifying concrete types and instead use abstract symbols that can substitute for any type.
* ''[[Subtyping]]'' (also called ''subtype polymorphism'' or ''inclusion polymorphism''): when a name denotes instances of many different classes related by some common superclass.<ref name="gbooch">{{cite book |last1=Conallen |first1=J. |last2=Engle |first2=M. |last3=Houston |first3=K. |last4=Maksimchuk |first4=R. |last5=Young |first5=B. |last6=Booch |first6=G. |author6-link=Grady Booch |date=2007 |title=Object-Oriented Analysis and Design with Applications |publisher=Pearson Education |edition=3rd |isbn=9780132797443 |pages=}}</ref>