Minor refactoring

[ghc-hetmet.git] / compiler / prelude / TysWiredIn.lhs

diff --git a/compiler/prelude/TysWiredIn.lhs b/compiler/prelude/TysWiredIn.lhs
index 83c3f45..3689479 100644 (file)
--- a/compiler/prelude/TysWiredIn.lhs
+++ b/compiler/prelude/TysWiredIn.lhs
@@ -3,12 +3,9 @@
 %
 \section[TysWiredIn]{Wired-in knowledge about {\em non-primitive} types}
 
-This module tracks the ``state interface'' document, ``GHC prelude:
-types and operations.''
-
 \begin{code}
 -- | This module is about types that can be defined in Haskell, but which
--- must be wired into the compiler nonetheless.
+--   must be wired into the compiler nonetheless.  C.f module TysPrim
 module TysWiredIn (
         -- * All wired in things
        wiredInTyCons, 
@@ -41,7 +38,7 @@ module TysWiredIn (
        mkListTy,
 
        -- * Tuples
-       mkTupleTy,
+       mkTupleTy, mkBoxedTupleTy,
        tupleTyCon, tupleCon, 
        unitTyCon, unitDataCon, unitDataConId, pairTyCon, 
        unboxedSingletonTyCon, unboxedSingletonDataCon,
@@ -329,6 +326,7 @@ unboxedPairDataCon :: DataCon
 unboxedPairDataCon = tupleCon   Unboxed 2
 \end{code}
 
+
 %************************************************************************
 %*                                                                     *
 \subsection[TysWiredIn-boxed-prim]{The ``boxed primitive'' types (@Char@, @Int@, etc)}
@@ -536,11 +534,17 @@ done by enumeration\srcloc{lib/prelude/InTup?.hs}.
 \end{itemize}
 
 \begin{code}
-mkTupleTy :: Boxity -> Int -> [Type] -> Type
-mkTupleTy boxity arity tys = mkTyConApp (tupleTyCon boxity arity) tys
+mkTupleTy :: Boxity -> [Type] -> Type
+-- Special case for *boxed* 1-tuples, which are represented by the type itself
+mkTupleTy boxity [ty] | Boxed <- boxity = ty
+mkTupleTy boxity tys = mkTyConApp (tupleTyCon boxity (length tys)) tys
+
+-- | Build the type of a small tuple that holds the specified type of thing
+mkBoxedTupleTy :: [Type] -> Type
+mkBoxedTupleTy tys = mkTupleTy Boxed tys
 
 unitTy :: Type
-unitTy = mkTupleTy Boxed 0 []
+unitTy = mkTupleTy Boxed []
 \end{code}
 
 %************************************************************************