Constraint technology for user-interface construction in ThingLab II
Jules Moloney, Alan H. Borning, Bjorn N. Freeman-Benson · 1989
ThingLab II is an object-oriented constraint programming system designed specifically for interactive user interface construction and implemented in Smalltalk-80 For constraints to be effective in building user interfaces, they must not impede the responsiveness of the user interface either at run time or during construction. The necessary speed is attained in ThingLab II by making judicious tradeoffs between compilation and interpretation, and by using a fast, incremental algorithm for constraint satisfaction. The resulting system allows user interface components to be assembled, tested, and modified expediently while maintaining interactive responsiveness.