The ergo attribute system

The Ergo Attribute System was designed to satisfy the requirements for attributes in a language-generic program derivation environment. It consists of three components: (1) an abstract data type of attributes that guarantees attribute consistency, (2) a Common Lisp implementation which combines demand-driven and incremental attribute evaluation in a novel way while allowing for attribute persistence over many generations of a program, and (3) an attribute-grammar compiler producing code based on this abstract data type from a high-level specification. Our experience with three major applications (one being the attribute-grammar compiler itself) confirms that the overhead in storing and accessing attributes incurred by our implementation scheme is more than offset by the gains from the demand-driven, incremental, and persistent nature of attribution.