Using a Visual Constraint Language for Data Display Specification.
Isabel F. Cruz · 1993
In this paper we introduce the U-term language, a constraint-based language that has a visual syntax, and allows for the declarative specification of the display of data. Other features of the U-term language include: (1) simplicity and genericity of the basic constructs; (2) ability to specify a variety of displays (pie charts, bar charts, etc.); (3) compatibility with the object-oriented framework of the database language doodle. 1 Introduction In this paper we present a new constraint-based language, the U-term language. This language provides: ffl A declarative and visual specification of the display of graphical objects with simple and generic constructs. ffl The ability to specify a variety of displays such as pie charts, bar charts, and graphs, using Cartesian or polar coordinates. ffl Easy integration in an object-oriented framework. The U-term language is a key component of doodle (Draw an Object-Oriented Database LanguagE ) [Cru92, Cru93a, Cru93b]. The main principle beh...