Object-based language
Encyclopedia
The term "object-based
language" may be used in a technical sense to describe any programming language that uses the idea of encapsulating state and operations inside "objects"
. Object-based languages need not support inheritance
or subtyping
, but those that do are also said to be "object-oriented"
. Object-based languages that do not support inheritance or subtyping are usually not considered to be true object-oriented languages.
Examples of object-oriented languages
include Simula
, Smalltalk
, C++
(whose object model was based on Simula's), Objective-C
(whose object model was based on Smalltalk's), Eiffel
, Python
, Ruby
, Java
, C#, Visual Basic .NET
and REALbasic
(an object-oriented BASIC dialect). An example of a language that is object-based but not object-oriented is Visual Basic
(VB). VB supports both objects and classes, but not inheritance, so it does not qualify as object-oriented.
(In practice, the term "object-based" is normally applied only to those object-based languages that are not also object-oriented. Although all object-oriented languages are also object-based, by definition, they are not normally referred to as such. Instead the terms "object-based" and "object-oriented" are normally used as mutually exclusive alternatives, rather than as categories that overlap.)
Sometimes the term "object-based" is applied to prototype-based languages, true object-oriented languages that do not have classes, but in which objects instead inherit their code and data directly from other "template" objects. An example of a commonly used prototype-based language is JavaScript
.
Both object-based and object-oriented languages (whether class-based or prototype-based) may be statically type-checked. Statically checking prototype-based languages can be difficult because these languages often allow objects to be dynamically extended with new behavior, and even to have their parent object (from which they inherit) changed, at run time.
Object-based
In general, object-based indicates that something such as a theory, language, or model is based on the concept of object.In computer science, the term object-based has two different senses:...
language" may be used in a technical sense to describe any programming language that uses the idea of encapsulating state and operations inside "objects"
Object (computer science)
In computer science, an object is any entity that can be manipulated by the commands of a programming language, such as a value, variable, function, or data structure...
. Object-based languages need not support inheritance
Inheritance (computer science)
In object-oriented programming , inheritance is a way to reuse code of existing objects, establish a subtype from an existing object, or both, depending upon programming language support...
or subtyping
Subtype
In programming language theory, subtyping or subtype polymorphism is a form of type polymorphism in which a subtype is a datatype that is related to another datatype by some notion of substitutability, meaning that program constructs, typically subroutines or functions, written to operate on...
, but those that do are also said to be "object-oriented"
Object-oriented programming
Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...
. Object-based languages that do not support inheritance or subtyping are usually not considered to be true object-oriented languages.
Examples of object-oriented languages
Object-oriented programming language
This is a list of object-oriented programming programming languages.-Languages with object-oriented features:*ABAP*Ada 95*AmigaE*BETA*Blue*Boo*C++*C#*COBOL*Cobra*ColdFusion*Common Lisp*COOL*CorbaScript*Clarion*CLU*Curl*D*Dylan*E*Eiffel...
include Simula
Simula
Simula is a name for two programming languages, Simula I and Simula 67, developed in the 1960s at the Norwegian Computing Center in Oslo, by Ole-Johan Dahl and Kristen Nygaard...
, Smalltalk
Smalltalk
Smalltalk is an object-oriented, dynamically typed, reflective programming language. Smalltalk was created as the language to underpin the "new world" of computing exemplified by "human–computer symbiosis." It was designed and created in part for educational use, more so for constructionist...
, C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
(whose object model was based on Simula's), Objective-C
Objective-C
Objective-C is a reflective, object-oriented programming language that adds Smalltalk-style messaging to the C programming language.Today, it is used primarily on Apple's Mac OS X and iOS: two environments derived from the OpenStep standard, though not compliant with it...
(whose object model was based on Smalltalk's), Eiffel
Eiffel (programming language)
Eiffel is an ISO-standardized, object-oriented programming language designed by Bertrand Meyer and Eiffel Software. The design of the language is closely connected with the Eiffel programming method...
, Python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
, Ruby
Ruby (programming language)
Ruby is a dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was first developed and designed by Yukihiro "Matz" Matsumoto...
, Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
, C#, Visual Basic .NET
Visual Basic .NET
Visual Basic .NET , is an object-oriented computer programming language that can be viewed as an evolution of the classic Visual Basic , which is implemented on the .NET Framework...
and REALbasic
REALbasic
Realbasic is the object-oriented dialect of the BASIC programming language used in Real Studio, a programming environment, developed and commercially marketed by Real Software, Inc of Austin, Texas for Mac OS X, Microsoft Windows, 32-bit x86 Linux and the web.- Language features :RB is a strongly...
(an object-oriented BASIC dialect). An example of a language that is object-based but not object-oriented is Visual Basic
Visual Basic
Visual Basic is the third-generation event-driven programming language and integrated development environment from Microsoft for its COM programming model...
(VB). VB supports both objects and classes, but not inheritance, so it does not qualify as object-oriented.
(In practice, the term "object-based" is normally applied only to those object-based languages that are not also object-oriented. Although all object-oriented languages are also object-based, by definition, they are not normally referred to as such. Instead the terms "object-based" and "object-oriented" are normally used as mutually exclusive alternatives, rather than as categories that overlap.)
Sometimes the term "object-based" is applied to prototype-based languages, true object-oriented languages that do not have classes, but in which objects instead inherit their code and data directly from other "template" objects. An example of a commonly used prototype-based language is JavaScript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
.
Both object-based and object-oriented languages (whether class-based or prototype-based) may be statically type-checked. Statically checking prototype-based languages can be difficult because these languages often allow objects to be dynamically extended with new behavior, and even to have their parent object (from which they inherit) changed, at run time.