{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
module Language.LOL.Typing.Expr.Write where

import Data.Maybe (Maybe(..))
import Data.Monoid ((<>))
import Data.Text.Buildable (Buildable(..))

import Language.LOL.Typing.Expr.Grammar

instance Buildable Expr where
	build expr =
		case expr of
		 Expr_Var nam -> build nam
		 Expr_App f x ->
			"(" <> build f <> " " <> build x <> ")"
		 Expr_Annot e sig ->
			"(" <> build e <> " : " <> build sig <> ")"
		 Expr_Let sig nam decl e ->
			"let " <> n <> " = " <> build decl <> " in " <> build e
			where n =
				case sig of
				 Just s -> "("<>build nam<>":"<>build s<>")"
				 Nothing -> build nam
		 Expr_Where sig nam decl e ->
			build e <> " where " <> n <> " = " <> build decl
			where n =
				case sig of
				 Just s -> "("<>build nam<>":"<>build s<>")"
				 Nothing -> build nam
		 Expr_Abst sig nam e ->
			"(" <> "\\" <> n <> " -> " <> build e <> ")"
			where n =
				case sig of
				 Just s -> "("<>build nam<>":"<>build s<>")"
				 Nothing -> build nam
instance Buildable Decl where
	build decl =
		case decl of
		 Decl_Let sig nam expr ->
			n <> " = " <> build expr
			where n =
				case sig of
				 Just s -> "("<>build nam<>":"<>build s<>")"
				 Nothing -> build nam