Visual programming language


In computing, a visual programming language is any programming language that lets users create programs by manipulating program elements graphically rather than by specifying them textually. A VPL allows programming with visual expressions, spatial arrangements of text and graphic symbols, used either as elements of syntax or secondary notation. For example, many VPLs are based on the idea of "boxes and arrows", where boxes or other screen objects are treated as entities, connected by arrows, lines or arcs which represent relations.

Definition

VPLs may be further classified, according to the type and extent of visual expression used, into icon-based languages, form-based languages, and diagram languages. Visual programming environments provide graphical or iconic elements which can be manipulated by users in an interactive way according to some specific spatial grammar for program construction.
The general goal of VPLs is to make programming more accessible to novices and to support programmers at three different levels
A visually transformed language is a non-visual language with a superimposed visual representation. Naturally visual languages have an inherent visual expression for which there is no obvious textual equivalent.
Current developments try to integrate the visual programming approach with dataflow programming languages to either have immediate access to the program state, resulting in online debugging, or automatic program generation and documentation. Dataflow languages also allow automatic parallelization, which is likely to become one of the greatest programming challenges of the future.
The Visual Basic, Visual C#, Visual J# etc. languages of the Microsoft Visual Studio IDE are not visual programming languages: the representation of algorithms etc. is textual even though the IDE embellishes the editing and debugging activities with a rich user interface. A similar consideration applies to most other rapid application development environments which typically support a form designer and sometimes also have graphical tools to illustrate control flow and data dependencies.
Parsers for visual programming languages can be implemented using graph grammars.

List of visual languages

The following contains a list of notable visual programming languages.

Educational

Many modern video games make use of behavior trees, which are in principle a family of simple programming languages designed to model behaviors for non-player characters. The behaviors are modeled as trees, and are often edited in graphical editors.

Systems / simulation