module Ast where

import Data.List (intercalate)
import Text.Parsec (SourcePos)

type Ident = String

data Type = Type String | FuncType [Type] (Maybe Type) deriving (Eq, Ord)

instance Show Type where
  show (Type t) = t
  show (FuncType params rtyp) =
    "(" ++ (intercalate ", " (fmap show params)) ++ ") -> " ++ case rtyp of
      Just t -> show t
      Nothing -> "()"

showList :: [Type] -> String
showList xs = intercalate ", " $ fmap show xs

type FuncParam = (Ident, Type, SourcePos)

data Expr
  = Num Integer SourcePos
  | BinOp Op Expr Expr
  | Var Ident SourcePos
  | -- fn [params] return body private pos
    Func Ident [FuncParam] (Maybe Type) [Expr] Bool SourcePos
  | Call Expr [Expr] SourcePos
  | Return (Maybe Expr) SourcePos
  | Module String SourcePos
  deriving (Eq, Ord, Show)

data Op
  = Plus
  | Minus
  | Mul
  | Div
  deriving (Eq, Ord, Show)

toFuncType :: [FuncParam] -> Maybe Type -> Type
toFuncType params rtyp =
  FuncType (map (\(_, t, _) -> t) params) rtyp