Class FeatureTopDownExpandRule

source code

             object --+        
                      |        
chart.AbstractChartRule --+    
                          |    
    chart.TopDownExpandRule --+
                              |
                             FeatureTopDownExpandRule

Known Subclasses:

• FeaturePredictorRule

A specialized version of the top down expand rule that operates on nonterminals whose symbols are FeatStructNonterminals. Rather tha simply comparing the nonterminals for equality, they are unified.

The top down expand rule states that:

• [A→α*B1β][i:j]

licenses the edge:

• [B2→*γ][j:j]

for each grammar production B2→γ, assuming that B1 and B2 can be unified.