Constraint-based languages and systems (abstract)
Bjorn N. Freeman-Benson, Alan H. Borning · 1992
A constraint is a relation that should be satisfied, for example, that a line remain horizontal, that a resistor in an electrical circuit simulation obey Ohms Law, or that the height of a bar in a bar chart be proportional to some number in an application program. Constraints have been used in a variety of languages and systems, particularly in user interface tool kits, in planning and scheduling, and in simulation. They provide an intuitive declarative style of programming that integrates well with object-oriented systems.