GUI
The GUI library included in K is based on that of A+, but it takes advantage of many features unique to K. K's GUI is declarative and data-driven, as opposed to most GUIs which are imperative. A window and the things in a window are contained in a normal data structure, usually a dictionary on the K Tree, and displayed with the $ operator. Information about a widget is kept in the variable's attributes. Every data type in K can function as a widget - just not necessarily very well.
But in K, the GUI library is so terse and easy to use that even for prototyping, developers often use a GUI interface rather than a command line. A minimal, not very pretty GUI Hello world in K is
`show$"Hello world"The latest version of the K programming language, known as "K4", no longer has a built-in GUI library.
Read more about this topic: K (programming Language)