Represents one input left of a join node. The queue points to
a sibling queue representing the other leg which should be joined
against.
author: Dave Reynolds version: $Revision: 1.11 $ on $Date: 2008/01/02 12:06:16 $
Constructor. The queue is not usable until it has been bound
to a sibling and a continuation node.
Parameters: A - set of variable indices which should match between the two inputs
Constructor. The queue is not usable until it has been bound
to a sibling and a continuation node.
Parameters: A - List of variable indices which should match between the two inputs
Propagate a token to this node.
Parameters: env - a set of variable bindings for the rule being processed. Parameters: isAdd - distinguishes between add and remove operations.