Polymorphism (computer science)

In programming language theory and type theory, polymorphism is the provision of a single interface to entities of different types or the use of a single symbol to represent multiple different types. The concept is borrowed from a principle in biology where an organism or species can have many different forms or stages. The most commonly recognized major classes 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.

History Interest in polymorphic type systems developed significantly in the 1990s, with practical implementations beginning to appear by the end of the decade. Ad hoc polymorphism and parametric polymorphism

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (10)

Related publications

Related people (1)

Related people

Related units (1)

Related units

Related concepts (50)

Related concepts

Related courses (14)

Related courses

Related lectures (22)

Related lectures

CS-112(g): Object oriented programming

Ce cours approfondit les connaissances en programmation présentées dans le cours ICC du 1er semestre. L'accent est mis sur l'approche «orientée objet» (en C++), la conception et la spécification de programmes via la réalisation d'une mini-application dans un projet réalisé par binôme.

CS-210: Functional programming

Understanding of the principles and applications of functional programming, the fundamental models of program execution, application of fundamental methods of program composition, meta-programming through the construction of interpreters and advanced programming techniques.

CS-452: Foundations of software

The course introduces the foundations on which programs and programming languages are built. It introduces syntax, types and semantics as building blocks that together define the properties of a program part or a language. Students will learn how to apply these concepts in their reasoning.

Miniboxing: An Encoding for Specialization

Cristian Talau

In the presence of parametric polymorphism, erasure-based languages such as Java and Scala handle primitives (boolean values, integers and floating point numbers) in a suboptimal way: in order to provide a uniform representation on the low level, all primitive values are stored in heap objects, in a process known as boxing. This leads to access overheads, wasteful usage of the heap space and broken cache locality. Specialization enables Scala to optimally handle primitive values in the context of generic classes, but this is done at the expense of duplicating classes up to 10 times for each type parameter, for each of the 9 Scala primitive types and heap objects. This prevents specialization of key classes in the Scala library, such as Function2, List, Map and so on. This project aims at testing the hypothesis that encoding several primitive types into a larger stack-based primitive type can maintain the performance of specialized code, while dramatically decreasing the generated bytecode size.

2012

Lightweight Polymorphic Effects

Philipp Haller, Martin Odersky, Lukas Rytz

Type-and-effect systems are a well-studied approach for reasoning about the computational behavior of programs. Nevertheless, there is only one example of an effect system that has been adopted in a wide-spread industrial language: Java’s checked exceptions. We believe that the main obstacle to using effect systems in day-to-day programming is their verbosity, especially when writing functions that are polymorphic in the effect of their argument. To overcome this issue, we propose a new syntactically lightweight technique for writing effect-polymorphic functions. We show its independence from a specific kind of side-effect by embedding it into a generic and extensible framework for checking effects of multiple domains. Finally, we verified the expressiveness and practicality of the system by implementing it for the Scala programming language.

Springer-Verlag2012

Working with Ada 9X classes

Ada 9X refines the Ada 83 concept of class and introduces class-wide types to support run-time polymorphism. We study how the Ada definition of class compares to other definitions of this term. We examine how run-time polymorphism is introduced in Ada 9X, how it relates to the different concepts of subtype, and how it compares with other forms of polymorphism. We also discuss the different uses of class-wide types, mainly as a means for dynamic binding (dispatching). However, since Ada 9X has adhered to the philosophy of building blocks, class-wide entities can be used for other purposes than dispatching. These uses are idioms that every programmer should be aware of. Some of these idioms are presented here. We also examine how classes are integrated with generics.

ACM Press1994

C++

C++ ('si:_plVs_plVs, pronounced "C plus plus" and sometimes abbreviated as CPP) is a high-level, general-purpose programming language created by Danish computer scientist Bjarne Stroustrup. First rele

Type system

In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a type (for example, integer, floating point, string) to every "term" (a word, phr

Object-oriented programming

Object-Oriented Programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or properti