Options for rule groups and rules

Rule groups and rules may also be annotated with an option list (options). This is a list of strings, enclosed in square brackets [] or appended after the keyword OPTIONS. If such an option is set, the semantical analysis, optimization and code generation phases of are performed in a rule group/rule specific way.

Current available rule group options are:

• CentralNeighborSetComparison, LocalNeighborSetComparison, DirectFixpointCheck
  knows three kinds of fixpoint detections for edge additive rules: central neighbor set comparison, local neighbor set comparison, and direct fixpoint check (section 3.9). Normally central neighbor set comparison is prefered over local neighbor set comparison. The flag can be used to override this default.
• NoFixpoint, Fixpoint Do not generate a fixpoint loop/generate a fixpoint loop for the rule group.

Current available rule options are:

• JOIN Use join code generation mode, even if on-the-fly was analysed.
• ETJoin (alpha-tested) Use element-test join code generation mode. This mode uses element tests instead of join equality conditions. It should for a lot of cases speedup the join, if element tests of the last functor of a path are possible in constant time.
• ETFilters (alpha-tested) Use element-test path pre-filtering. Paths are generated several times, the first times for pre-selections.
• LocalTests Perform the pattern matching on a node always, if an instance of the node is traversed. This option results in more pattern matching tests, but fewer traversals, because the join search space of path problems is diminished.