lib/bmg/operator/allbut.rb in bmg-0.18.0 vs lib/bmg/operator/allbut.rb in bmg-0.18.1

@@ -61,14 +61,36 @@
         [:allbut, operand.to_ast, butlist.dup]
       end
 
     protected ### optimization
 
+      def _allbut(type, butlist)
+        operand.allbut(self.butlist|butlist)
+      end
+
+      def _matching(type, right, on)
+        # Always possible to push the matching, since by construction
+        # `on` can only use attributes that have not been trown away,
+        # hence they exist on `operand` too.
+        operand.matching(right, on).allbut(butlist)
+      end
+
       def _restrict(type, predicate)
         operand.restrict(predicate).allbut(butlist)
       end
 
+      def _page(type, ordering, page_index, options)
+        return super unless self.preserving_key?
+        operand.page(ordering, page_index, options).allbut(butlist)
+      end
+
     protected ### inspect
+
+      def preserving_key?
+        operand.type.knows_keys? && operand.type.keys.find{|k|
+          (k & butlist).empty?
+        }
+      end
 
       def args
         [ butlist ]
       end