diff --git a/src/runtime/haskell/PGF.hs b/src/runtime/haskell/PGF.hs
index 3b8eced42..c387521a7 100644
--- a/src/runtime/haskell/PGF.hs
+++ b/src/runtime/haskell/PGF.hs
@@ -30,6 +30,7 @@ module PGF(
            Type, Hypo,
            showType, readType,
            mkType, mkHypo, mkDepHypo, mkImplHypo,
+           unType,
            categories, startCat,
 
            -- * Functions
diff --git a/src/runtime/haskell/PGF/Type.hs b/src/runtime/haskell/PGF/Type.hs
index 70604a123..e3cf46eec 100644
--- a/src/runtime/haskell/PGF/Type.hs
+++ b/src/runtime/haskell/PGF/Type.hs
@@ -1,6 +1,7 @@
 module PGF.Type ( Type(..), Hypo,
                   readType, showType,
                   mkType, mkHypo, mkDepHypo, mkImplHypo,
+                  unType,
                   pType, ppType, ppHypo ) where
 
 import PGF.CId
@@ -51,6 +52,9 @@ mkDepHypo x ty = (Explicit,x,ty)
 mkImplHypo :: CId -> Type -> Hypo
 mkImplHypo x ty = (Implicit,x,ty)
 
+unType :: Type -> ([Hypo], CId, [Expr])
+unType (DTyp hyps cat es) = (hyps, cat, es)
+
 pType :: RP.ReadP Type
 pType = do
   RP.skipSpaces