A programming language framework for designing user interfaces

Programming Language researchers increasingly recognize that a high proportion of application development costs involve the interface with users of the application, including various dialogues, input formats, error checking, help and explanation messages, and the like. They also increasingly recognize that maintenance costs tend to overshadow development costs. These two factors even multiply their adverse effects: as the user needs evolve, it is the interface with a system which generally requires the most maintenance. The user relationship is even said to account for about 60 percent of the maintenance problem [Lientz and Swanson 81]. Surprisingly, few programming language constructs are designed to address the area of user interface design. On the contrary, traditional programming language constructs are strongly oriented towards improving programmers' effectiveness in developing the algorithmic and data manipulation aspects of an application. A programmer is basically left to reinvent each time the required procedures to deal with user commands and inputs.