In computer science, separation of concerns (SoC) is the process of breaking a program into distinct features that overlap in functionality as little as possible. A concern is any piece of interest or focus in a program. Typically, concerns are synonymous with features or behaviors. Wikibooks Wikiversity has more about this subject: School of Computer Science Open Directory Project: Computer Science Downloadable Science and Computer Science books Collection of Computer Science Bibliographies Belief that title science in computer science is inappropriate Categories: ‪Wikipedia articles needing priority cleanup‬ | ‪Computer science‬ ... In computer science, a concern is a problem which a program tries to solve. ... In geographic information systems, a feature comprises an item of feature data. ...

All programming paradigms aid developers in the process of SoC. For example, object-oriented programming languages such as the Java programming language can separate concerns into classes and methods. Procedural programming languages such as C and Pascal can separate concerns into procedures. Aspect-oriented programming languages can separate concerns into aspects. A programming paradigm is a paradigmatic style of programming (compare with a methodology which is a paradigmatic style of doing software engineering). ... In computer science, object-oriented programming, OOP for short, is a computer programming paradigm. ... Java is an object-oriented programming language developed initially by James Gosling and colleagues at Sun Microsystems. ... In, object-oriented programming, a class consists of a collection of types of encapsulated instance variables and types of methods, possibly with implementation of those types together with a constructor function that can be used to create objects of the class. ... Used mainly in object-oriented programming, the term method refers to a piece of code that is exclusively associated either with a class (called class methods or static methods) or with an object (called instance methods). ... Procedural programming is a programming paradigm based upon the concept of the procedure call. ... C (lowercase c) is the third letter of the Roman alphabet. ... The pascal (symbol Pa) is the SI unit of pressure. ... In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one, or more, statement blocks; such code is sometimes collected into software libraries. ... In software engineering, the programming paradigm of aspect-oriented programming (AOP), also called aspect-oriented software development (AOSD), attempts to aid programmers in the separation of concerns, or the breaking down of a program into distinct parts that overlap in functionality as little as possible. ... In computer science, an aspect is a part of a program that cross-cuts its core concerns, therefore violating its separation of concerns. ...

Progress towards SoC is traditionally achieved through modularity, encapsulation, and information hiding. Modularity is a concept that has applications in the contexts of computer science, particularly programming, as well as cognitive science in investigating the structure of mind. ... Encapsulation may refer to: (in the vernacular) expressing an idea with few words, such as with an adage, proverb, slogan, or jingle (in software engineering) the use of information hiding within a program (in electronics) the design and manufacture of protective packages for integrated circuit encapsulation (in biomedical engineering) a... // Overview In computer science, the principle of information hiding is the hiding of design decisions in a computer program that are most likely to change, thus protecting other parts of the program from change if the design decision is changed. ...

Origin

The term separation of concerns was probably coined by Edsger W. Dijkstra in his paper On the role of scientific thought. Portrait of Edsger Dijkstra (courtesy Brian Randell) Edsger Wybe Dijkstra (Rotterdam, May 11, 1930 – Nuenen, August 6, 2002) was a Dutch computer scientist. ...

Let me try to explain to you, what to my taste is characteristic for all intelligent thinking. It is, that one is willing to study in depth an aspect of one's subject matter in isolation for the sake of its own consistency, all the time knowing that one is occupying oneself only with one of the aspects. We know that a program must be correct and we can study it from that viewpoint only; we also know that it should be efficient and we can study its efficiency on another day, so to speak. In another mood we may ask ourselves whether, and if so: why, the program is desirable. But nothing is gained --on the contrary!-- by tackling these various aspects simultaneously. It is what I sometimes have called "the separation of concerns", which, even if not perfectly possible, is yet the only available technique for effective ordering of one's thoughts, that I know of. This is what I mean by "focussing one's attention upon some aspect": it does not mean ignoring the other aspects, it is just doing justice to the fact that from this aspect's point of view, the other is irrelevant. It is being one- and multiple-track minded simultaneously.

Examples

eXtensible HyperText Markup Language and Cascading Style Sheets are languages intended to separate style from content. Where XHTML elements define the abstract structure of a document, CSS directives are interpreted by the web browser to render those elements in visual form. In practice, one must sometimes alter XHTML in order to obtain the desired result with CSS, in part because style and content are not completely orthogonalized by any existing browser implementation of CSS, and in part because CSS does not allow one to remap the document tree. The Extensible HyperText Markup Language, or XHTML, is a markup language that has the same expressive possibilities as HTML, but a stricter syntax. ... In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ... The Extensible HyperText Markup Language, or XHTML, is a markup language that has the same expressive possibilities as HTML, but a stricter syntax. ... In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ... Web browser shortcuts on an Apple computer A web browser is a software application that enables a user to display and interact with HTML documents hosted by web servers or held in a file system. ... The Extensible HyperText Markup Language, or XHTML, is a markup language that has the same expressive possibilities as HTML, but a stricter syntax. ... In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ... In linear algebra, orthogonalization means the following: we start with vectors v1,...,vk in an inner product space, most commonly the Euclidean space Rn which are linearly independent and we want to find mutually orthogonal vectors u1,...,uk which generate the same subspace as the vectors v1,...,vk. ... Web browser shortcuts on an Apple computer A web browser is a software application that enables a user to display and interact with HTML documents hosted by web servers or held in a file system. ... In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ... In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ...

See also

• procedural programming
• object-oriented programming
• aspect-oriented programming
• aspect
• core concern
• cross-cutting concern.
• modularity (programming)
• encapsulation