Flexible unparsing in a structure editing environment

Generators of structure editing-based programming environments require some form of unparse specification language with which an implementor can describe mappings between objects in the programming environment and concrete, visual representations of them. They must also provide an unparser to execute those mappings in a running programming environment. We descr ibe one such unparse specification language, called VIZ , and its unparser, called UAL . V IZ combines in a uniform descriptive framework a variety of capabilities to descr ibe flexible views of a programming database using a library of high-level formatting routines that can be customized and extended by the implementor. T h e U A L unparser allows the highly conditional unparse mappings of V IZ to be executed efficiently. Its implementation is based on the automatic generation of explicit display views, together with a scheme for efficient incremental updating of them in response to arbitrary changes to objects in the programming environment. Th is research is supported in part by the Software Engineering Division of C E N T A C S / C O R A D C O M , Fort Monmouth, N J . University Libraries Cf\r r University Table of