Strictness Analysis for Attribute Grammars

Attribute grammars may be seen as a (rather specialised) lazy or demand-driven programming language. The ``programs'' in this language take text or parse trees as input and return values of the synthesised attributes to the root as output. From this observation we establish a framework for abstract interpretation of attribute grammars. The framework is used to construct a strictness analysis for attribute grammars. Results of the analysis enable us to transform an attribute grammar such that attributes are evaluated during parsing, if possible. The analysis is proved correct by relating it to a fixpoint semantics for attribute grammars. An implementation of the analysis is discussed and some extensions to the analysis are mentioned.