Decorated Attribute Grammars
The paper “Decorated Attribute Grammars” by Lennart Kats, Tony Sloane and Eelco Visser has been accepted for presentation at the International Conference on Compiler Construction (CC 2009) to be held in March 2009 in York (UK). [pdf]
Abstract Attribute grammars are a powerful specification formalism for tree-based computation, particularly for software language processing. Various extensions have been proposed to abstract over common patterns in attribute grammar specifications. These include various forms of copy rules to support non-local dependencies, collection attributes, and expressing dependencies that are evaluated to a fixed point. Rather than implementing extensions natively in an attribute evaluator, we propose attribute decorators that describe an abstract evaluation mechanism for attributes, making it possible to provide such extensions as part of a library of decorators. Inspired by strategic programming, they are specified using generic traversal operators. To demonstrate their effectiveness, we describe how to employ decorators in name, type, and flow analysis.
The ideas have been implemented in Aster, an extension of Stratego with reference attribute grammars.