wip for #451

still to do: apply remaining rewrite_rules

pyterrier/anserini/retriever.py

@@ -1,3 +1,4 @@
+from typing import Optional
 from warnings import warn
 import pandas as pd
 import pyterrier as pt
@@ -119,3 +120,12 @@ def transform(self, queries):
 
         res_dt = pd.DataFrame(results, columns=['qid', 'query'] + ["docno"] + ['rank', 'score'])
         return res_dt
+
+    def fuse_rank_cutoff(self, k: int) -> Optional[pt.Transformer]:
+        """
+        Support fusing with RankCutoffTransformer.
+        """
+        if self.k < k:
+            return self # the applied rank cutoff is greater than the one already applied
+        # apply the new k
+        return AnseriniBatchRetrieve(self.index_location, k=k, wmodel=self.wmodel, verbose=self.verbose)