This work is directed towards incremental semantic analysis for object-oriented programming languages. These languages have comparatively complex static-semantics which could not be adequately handled with earlier techniques such as attribute grammars.
The main contribution of this work is a new technique for developing incremental semantic analyzers: Door Attribute Grammars. This technique extends standard attribute grammars by allowing objects and references to be specified as part of the attribution of a syntax tree. Special "door"-objects act as an interface between the syntax tree and its object attribution. This extension results in space-efficient attributions for which incremental updates can be performed efficiently. In particular, the complex naming semantics of object-oriented languages can be handled in a straight forward way by attributing the tree with explicit visibility graphs built using objects and references.
The price for using objects and references in an attribution is that non-local attribute dependencies are introduced which prevent incremental attribute evaluators to be generated completely automatically from the grammar. We solve this problem by splitting the grammar in two parts: one part (the main grammar) which can be treated by automatic methods, and another part (the door package) for which a manual, but systematic, implementation technique is developed. A door package can implement general aspects of a family of programming languages. To specify a new language in the supported family it suffices to write a main grammar, using the door package as a tool box.
The techniques have been developed and tested in practice. A complete incrementally compiling environment has been built: Mjolner/Orm, which currently supports the major part of Simula.