added configuration file which defines the heads for all syntactic functions in ParseEng

treebanks/PennTreebank/Dependencies.hs

@@ -0,0 +1,37 @@
+module Dependencies where
+
+import PGF
+import qualified Data.Map as Map
+import Data.Maybe as Maybe
+
+type HeadTable = Map.Map CId [CId]
+
+readHeadTable :: FilePath -> IO HeadTable
+readHeadTable fpath = do
+  ls <- fmap lines $ readFile fpath
+  return (Map.fromList [(head ws, tail ws) | l <- ls, let ws = map mkCId (words l), not (null ws)])
+
+getDependencies :: HeadTable -> Expr -> (CId,[(CId,CId)])
+getDependencies tbl e = 
+  case unApp e of
+    Just (f,es)
+      | null es   -> (f,[])
+      | f == mkCId "MkSymb" -> (f,[])
+      | otherwise -> case Map.lookup f tbl of
+                       Just cs -> let xs       = zipWith (\c e -> (c,getDependencies tbl e)) cs es
+                                      hes      = [he | (c,he) <- xs, c == c_head]
+                                      (h,deps) = head hes
+                                  in if length hes /= 1
+                                       then error ("there must be exactly one head in "++showExpr [] e)
+                                       else (h,concat (deps:[(h,m):deps | (c,(m,deps)) <- xs, c == c_mod]))
+                       Nothing -> error ("there is no head defined for function "++showCId f)
+    Nothing       -> error ("this is not a function application: "++showExpr [] e)
+
+c_head = mkCId "head"
+c_mod  = mkCId "mod"
+
+test = do
+  t <- readHeadTable "ParseEngAbs.heads" 
+  es <- fmap (concatMap (maybeToList . readExpr) . lines) $ readFile "wsj.full"
+  let deps = Map.fromListWith (+) [(d,1) | e <- es, d <- snd (getDependencies t e)]
+  writeFile "deps" (unlines (map show (Map.toList deps)))