XXL: A Visual+Textual Environment for Building Graphical User Interfaces

This paper presents XXL, a visual+textual environment for the automated building of graphical user interfaces. This system uses a declarative language which is a subset of the C language and can either be interpreted or compiled. It includes an interactive builder that can both handle graphical and non-graphical objects. This tool makes it possible to create highly customized interfaces by visual programming or by “sketching” early interface ideas that are automatically interpreted by the system to produce executable GUI objects. This builder is based on the concept of textual+visual equivalence and is able to re-edit and modify any legible source code, not only the code it itself produced. This environment is thus a truly open system that can cooperate with higher-level tools.