A Language Supporting Direct Manipulation of Component-based Object Construction and Deconstruction in Collaborative Croquet Spaces

We describe the language architecture of Brie, a framework for authoring 3D spaces and user interfaces. Brie is designed to take advantage of the unique social characteristics of the Croquet collaboration architecture, in particular by lowering the bar for content creation, thus greatly expanding the community of content developers. This is achieved through a 3D direct-manipulation interface to objects. To support this, the Brie architecture consists of a prototype-based language extension to Squeak with flexible inheritance, demand-driven evaluation, dependency-directed backtracking, and a special copy algorithm that conditionally copies dependent references