module CC.Typed(
    module CC.Typed,
    module CC.Types
) where

import CC.Pretty
import CC.Types


data ProgramT = ProgramT [DeclT]
  deriving (Show, Read)

data DeclT = DefT DefT  -- import?
  deriving (Show, Read)

data DefT = FunctionT TypeT Name [Name] ExprT
  deriving (Show, Read)

data TypeT = TFunT TypeT TypeT
           | TIntT
           | TyVar Int
  deriving (Show, Read)

data ExprT = CallT TypeT ExprT ExprT
           | IntT Int
           | VarT Occ
  deriving (Show, Read)

-- | Occurrence of a variable
data Occ = Occ Name TypeT
  deriving (Show, Read)

exprType :: ExprT -> TypeT
exprType (CallT typ _ _) = typ
exprType (IntT _) = TIntT
exprType (VarT (Occ _ typ)) = typ

instance Pretty TypeT where
    prettyPrec _ TIntT = "Int"
    prettyPrec p (TFunT a b) =
        precParens p 2 (prettyPrec 3 a ++ " -> " ++ prettyPrec 2 b)
    prettyPrec _ (TyVar i) = 't' : show i

instance Pretty ExprT where
    prettyPrec p (LamT ty (Occ n t) e) =
        precParens p 2 $
            "(\\(" ++ n ++ " :: " ++ pretty t ++ ") -> "
                ++ prettyPrec 2 e ++ ") :: " ++ pretty ty
    prettyPrec p (CallT ty e1 e2) =
        precParens p 2 $
            prettyPrec 3 e1 ++ " " ++ prettyPrec 3 e2 ++ " :: " ++ pretty ty
    prettyPrec _ (IntT i) = show i
    prettyPrec p (VarT (Occ n t)) =
        precParens p 2 $
            show n ++ " :: " ++ pretty t

instance Pretty DefT where
    pretty (FunctionT n e) = n ++ " = " ++ pretty e

instance Pretty DeclT where
    pretty (DefT def) = pretty def

instance Pretty ProgramT where
    pretty (ProgramT decls) = concatMap ((++ "\n") . pretty) decls