A data flow evaluator for attribute grammars

The attribute evaluation is accomplished in one bottom-up pass and data flow fashion. This results in a fast and parallel evaluation of the attribute instances. The bottom-up evaluator uses one FIFO (first-in, first-out) queue which initially holds the leaf attributes with known values in the reverse dependency graph. The reverse dependency graph shows the dependency of the attributes on each other and the order in which they are evaluated. The attributes in the queue give their values to their predecessor attributes. A predecessor attribute needs these values to be evaluated