rebalance word transition penalties

src/nominatim_api/search/query.py

@@ -214,6 +214,19 @@ class QueryNode:
         types of tokens spanning over the gap.
     """
 
+    @property
+    def word_break_penalty(self) -> float:
+        """ Penalty to apply when a words ends at this node.
+        """
+        return max(0, self.penalty)
+
+    @property
+    def word_continuation_penalty(self) -> float:
+        """ Penalty to apply when a word continues over this node
+            (i.e. is a multi-term word).
+        """
+        return max(0, -self.penalty)
+
     def name_address_ratio(self) -> float:
         """ Return the propability that the partial token belonging to
             this node forms part of a name (as opposed of part of the address).
@@ -273,7 +286,8 @@ class QueryStruct:
         self.source = source
         self.dir_penalty = 0.0
         self.nodes: List[QueryNode] = \
-            [QueryNode(BREAK_START, source[0].ptype if source else PHRASE_ANY)]
+            [QueryNode(BREAK_START, source[0].ptype if source else PHRASE_ANY,
+                       0.0, '', '')]
 
     def num_token_slots(self) -> int:
         """ Return the length of the query in vertice steps.
@@ -338,6 +352,13 @@ class QueryStruct:
         assert ttype != TOKEN_PARTIAL
         return self.nodes[trange.start].get_tokens(trange.end, ttype) or []
 
+    def get_in_word_penalty(self, trange: TokenRange) -> float:
+        """ Gets the sum of penalties for all token transitions
+            within the given range.
+        """
+        return sum(n.word_continuation_penalty
+                   for n in self.nodes[trange.start + 1:trange.end])
+
     def iter_partials(self, trange: TokenRange) -> Iterator[Token]:
         """ Iterate over the partial tokens between the given nodes.
             Missing partials are ignored.