Model–view–controller
Model–view–controller (MVC) is a software design pattern commonly used for developing user interfaces that divides the related program logic into three interconnected elements. This is done to separate internal representations of information from the ways information is presented to and accepted from the user. Traditionally used for desktop graphical user interfaces (GUIs), this pattern became popular for designing web applications. Popular programming languages have MVC frameworks that facilitate the implementation of the pattern. TOC One of the seminal insights in the early development of graphical user interfaces, MVC became one of the first approaches to describe and implement software constructs in terms of their responsibilities. Trygve Reenskaug created MVC while working on Smalltalk-79 as a visiting scientist at the Xerox Palo Alto Research Center (PARC) in the late 1970s. He wanted a pattern that could be used to structure any program where users interact with a large, convoluted data set. His design initially had four parts: Model, View, Thing, and Editor. After discussing it with the other Smalltalk developers, he and the rest of the group settled on Model, View, and Controller instead. In their final design, a Model represents some part of the program purely and intuitively. A View is a visual representation of a Model, retrieving data from the Model to display to the user and passing requests back and forth between the user and the Model. A Controller is an organizational part of the user interface that lays out and coordinates multiple Views on the screen, and which receives user input and sends the appropriate messages to its underlying Views. This design also includes an Editor as a specialized kind of Controller used to modify a particular View, and which is created through that View. Smalltalk-80 supports a version of MVC that evolved from this one. It provides abstract View and Controller classes as well as various concrete subclasses of each that represent different generic widgets.
