Ruby representation of the Pathfinder-Algebra (http://www-db.informatik.uni-tuebingen.de/research/pathfinder). This gem provides a Ruby interface to the Pathfinder-Algebra. Taking an algebraic plan in XML, Pathfinder is able to generate code for various database systems (SQL-99 conformant, MonetDB, X100, ...). In order to generate efficient target code it also does heavy optimization on the input plans.