Reference Attributed Grammars

An extension to canonical attribute grammars is introduced, permitting attributes to be references to arbitrary nodes in the syntax tree, and attributes to be accessed via the reference attributes. Important practical problems such as name and type analysis for object-oriented languages can be expressed concisely in these grammars, and an optimal evaluation algorithm is available. The proposed formalism and algorithm have been implemented in an interactive language development tool. 1 Introduction Canonical attribute grammars (AGs), as introduced by Knuth [20], is an appealing formalism that allows context -sensitive properties of individual constructs in a language to be described in a declarative way, and to be automatically computed for any program in the language. Important applications include defining context-sensitive syntax and code generation for a language. A major problem with canonical AGs is that the specifications often become too low-level when dealing with non-local de..