added function treeProbability in the Haskell binding

src/runtime/haskell-bind/PGF2.hsc

@@ -39,6 +39,8 @@ module PGF2 (-- * PGF
              mkFloat,unFloat,
              mkMeta,unMeta,
              mkCId,
+             treeProbability,
+
              -- ** Types
              Type, Hypo, BindType(..), startCat,
              readType, showType,
@@ -314,6 +316,13 @@ compute (PGF p _) (Expr c_expr touch1) =
               gu_pool_free exprPl
               throwIO (PGFError msg)
 
+treeProbability :: PGF -> Expr -> Float
+treeProbability (PGF p _) (Expr c_expr touch1) =
+  unsafePerformIO $ do
+    res <- pgf_compute_tree_probability p c_expr
+    touch1
+    return (realToFrac res)
+
 -----------------------------------------------------------------------------
 -- Graphviz
 

src/runtime/haskell-bind/PGF2/FFI.hs

@@ -325,6 +325,9 @@ foreign import ccall "pgf/pgf.h pgf_expr_unlit"
 foreign import ccall "pgf/expr.h pgf_expr_arity"
   pgf_expr_arity :: PgfExpr -> IO CInt
 
+foreign import ccall "pgf/expr.h pgf_compute_tree_probability"
+  pgf_compute_tree_probability :: Ptr PgfPGF -> PgfExpr -> IO CFloat
+
 foreign import ccall "pgf/expr.h pgf_check_expr"
   pgf_check_expr :: Ptr PgfPGF -> Ptr PgfExpr -> PgfType -> Ptr GuExn -> Ptr GuPool -> IO ()