module Language.C where


data Program = Program [FunDef]
  deriving (Show)

data FunDef
    = FunDef FunAttrs Type Name [(Type, Name)] StExpr
    | ProcDef FunAttrs Name [(Type, Name)] [Stmt]
  deriving (Show, Eq)

data FunAttrs = FunAttrs
    { faStatic :: Bool }
  deriving (Show, Eq)

defAttrs :: FunAttrs
defAttrs = FunAttrs { faStatic = False }

-- | Some C types.
data Type
    = TInt Bits
    | TUInt Bits
    | TFloat
    | TDouble
    | TPtr Type
  deriving (Show, Eq)

-- | The number of bits in a C integral type.
data Bits = B8 | B16 | B32 | B64
  deriving (Show, Eq)

-- | A C variable or function name.
newtype Name = Name String
  deriving (Show, Eq, Ord)

-- Statement expression: conceptually gcc's ({ ... })
data StExpr = StExpr [Stmt] Expr
  deriving (Show, Eq)

data Stmt
    = SDecl Type Name (Maybe Expr)
    | SAsg Name Expr
    | SStore Name Expr Expr  -- ^ name[expr] = expr
    | SCall Name [Expr]
    -- | @SFor ty i lo hi body@: @for (ty i = lo; i < hi; i++) body@
    | SFor Type Name Expr Expr [Stmt]
    -- | @SWhile pre cond post@: @while (true) { pre; if (!cond) break; post; }@
    -- Special case if @pre == []@: @while (cond) { post; }
    | SWhile [Stmt] Expr [Stmt]
    | SIf Expr [Stmt] [Stmt]
  deriving (Show, Eq)

data Expr
    = EOp Expr String Expr
    | ENot Expr  -- ^ @!expr@
    | ELit String
    | EVar Name
    | ECall Name [Expr]
    | EIndex Name Expr
    | EPtrTo Expr
    | ESizeOf Type
    | ECast Type Expr
  deriving (Show, Eq)


fundefName :: FunDef -> Name
fundefName (FunDef _ _ n _ _) = n
fundefName (ProcDef _ n _ _) = n