Typeinference/checking on expressions done.
Simplified the typechecker a bit, removed GADT solution for now. Still not fully working
This commit is contained in:
sebastianselander
parent
b6b2dfa25f
commit
be3fcfc9e3
5 changed files with 153 additions and 63 deletions
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@ -9,9 +9,9 @@ separator Type "->";
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EId. Exp3 ::= Ident ;
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EInt. Exp3 ::= Integer ;
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-- EApp. Exp2 ::= Exp2 Exp3 ;
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EApp. Exp2 ::= Exp2 Exp3 ;
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EAdd. Exp1 ::= Exp1 "+" Exp2 ;
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-- EAbs. Exp ::= "\\" Ident ":" Type "." Exp ;
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EAbs. Exp ::= "\\" Ident ":" Type "." Exp ;
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coercions Exp 3 ;
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TInt. Type1 ::= "Int" ;
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@ -17,7 +17,7 @@ extra-source-fiels:
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common warnings
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ghc-options: -Wall
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ghc-options: -W
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executable language
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import: warnings
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@ -30,8 +30,10 @@ executable language
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Grammar.Par
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Grammar.Print
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Grammar.Skel
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Grammar.ErrM
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Interpreter
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TypeChecker
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NewAbs
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hs-source-dirs: src
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@ -4,6 +4,7 @@ module Main where
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import Control.Monad.Except (runExcept)
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import Grammar.Par (myLexer, pProgram)
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import Interpreter (interpret)
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import TypeChecker (typecheck)
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import System.Environment (getArgs)
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import System.Exit (exitFailure, exitSuccess)
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@ -17,6 +18,11 @@ main = getArgs >>= \case
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putStrLn "SYNTAX ERROR"
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putStrLn err
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exitFailure
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Right p -> case typecheck p of
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Left err -> do
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putStrLn "TYPECHECKING ERROR"
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putStrLn err
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exitFailure
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Right prg -> case runExcept $ interpret prg of
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Left err -> do
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putStrLn "INTERPRETER ERROR"
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29
src/NewAbs.hs
Normal file
29
src/NewAbs.hs
Normal file
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@ -0,0 +1,29 @@
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{-# LANGUAGE GADTs, LambdaCase #-}
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module NewAbs where
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import Grammar.Abs ( Ident(..), Type )
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data CExp where
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CId :: Type -> Ident -> CExp
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CInt :: Type -> Int -> CExp
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CAdd :: Type -> CExp -> CExp -> CExp
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CAbs :: Type -> Ident -> Type -> CExp -> CExp
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CApp :: Type -> CExp -> CExp -> CExp
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instance Show CExp where
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show :: CExp -> String
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show = \case
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CId _ (Ident a) -> show a
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CInt _ i -> show i
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CAdd _ e1 e2 -> show e1 <> " + " <> show e2
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CAbs t1 i t2 e -> appendType t1 $ show "\\" <> show i <> " : " <> show t2 <> ". " <> show e
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CApp _ e1 e2 -> show e1 <> " " <> show e2
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appendType :: Type -> String -> String
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appendType t s = s <> " : " <> show t
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data CDef = CDef Ident Type Ident [Ident] CExp
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deriving Show
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newtype CProgram = CProgram [CDef]
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@ -1,76 +1,129 @@
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{-# LANGUAGE LambdaCase #-}
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{-# LANGUAGE GADTs #-}
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{-# LANGUAGE TypeApplications #-}
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{-# LANGUAGE OverloadedRecordDot #-}
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module TypeChecker where
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module TypeChecker (typecheck) where
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import Grammar.Abs
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import Grammar.ErrM
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import Data.Kind qualified as T
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import Data.String qualified
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import Grammar.ErrM ( Err )
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import NewAbs
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import Data.Map (Map)
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import Data.Map qualified as Map
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import Control.Monad.Reader
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import Control.Monad.Except
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import Data.List (isPrefixOf)
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import Control.Applicative ((<|>))
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newtype Env = Env { signature :: Map Ident CType }
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type Check a = ReaderT Context Err a
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type Check a = ReaderT Env Err a
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data Context = Ctx { sig :: Map Ident Type
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, env :: [Map Ident Type]
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}
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initEnv :: Env
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initEnv = Env { signature = mempty }
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initEnv :: Context
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initEnv = Ctx { sig = mempty
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, env = mempty
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}
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run :: Check a -> Either String a
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run = flip runReaderT initEnv
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checkProg :: Program -> Check Program
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checkProg (Program ds) = Program <$> mapM checkDef ds
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typecheck :: Program -> Err Program
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typecheck prg = case run $ checkProg prg of
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Left err -> fail err
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Right _ -> pure prg
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checkDef :: Def -> Check Def
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checkDef = \case
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(DExp n1 TInt n2 params e) -> undefined
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(DExp n1 (TPol (Ident t)) n2 params e) -> undefined
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(DExp n1 ts n2 params e) -> undefined
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class Typecheck a where
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checkExp :: Exp -> Check (CExp a)
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checkProg :: Program -> Check CProgram
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checkProg (Program ds) = undefined
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checkDef :: Def -> Check CDef
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checkDef (DExp i1 TInt i2 args e) = undefined
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checkDef (DExp i1 (TPol i) i2 args e) = undefined
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checkDef (DExp i1 (TFun xs) i2 args e) = do
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when (i1 /= i2) (fail $ "Mismatched names: " <> show i1 <> " != " <> show i2)
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case compare (length xs - 1) (length args) of
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LT -> fail $ "Too many arguments, got " <> show (length args) <> " expected " <> show (length xs)
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_ -> do
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let vars = Map.fromList $ zip args xs
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e' <- local (\r -> r { env = [vars] }) (checkExp e)
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return $ CDef i1 (TFun xs) i2 args e'
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checkExp :: Exp -> Check CExp
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checkExp = \case
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EInt i -> pure $ CInt TInt (fromIntegral i)
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instance Typecheck Int where
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checkExp = \case
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EInt i -> pure $ CInt (fromIntegral i)
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EAdd e1 e2 -> do
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e1' <- checkExp @Int e1
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e2' <- checkExp @Int e2
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return $ CAdd e1' e2'
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EId (Ident i) -> asks (lookupSig (Ident i)) >>= liftEither >>= \case
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TCInt -> pure (CId (CIdent i))
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_ -> throwError $ "Unbound variable " <> show i
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e1' <- checkExp e1
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e2' <- checkExp e2
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let t1 = getType e1'
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let t2 = getType e2'
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when (t1 /= t2) (fail $ "Different types occured, got " <> show t1 <> " and " <> show t2)
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return $ CAdd t1 e1' e2'
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data CExp :: T.Type -> T.Type where
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CId :: CIdent -> CExp a
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CInt :: Int -> CExp Int
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CAdd :: Num a => CExp a -> CExp a -> CExp a
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EId i -> do
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asks (lookupEnv i) >>= \case
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Right t -> return $ CId t i
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Left _ -> asks (lookupSig i) >>= \case
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Right t -> return $ CId t i
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Left x -> fail x
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instance Show (CExp a) where
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show = \case
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CId (CIdent a) -> show a
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CInt i -> show i
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CAdd e1 e2 -> show e1 <> " + " <> show e2
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EAbs i t e -> do
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e' <- local (\r -> r { env = Map.singleton i t : r.env }) (checkExp e)
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return $ CAbs (TFun [t, getType e']) i t e'
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data CDef a = CDef CIdent CType CIdent [CIdent] (CExp a)
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deriving Show
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EApp e1 e2 -> do
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e1' <- checkExp e1
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e2' <- checkExp e2
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let retT = applyType (getType e1') (getType e2')
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case retT of
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Left x -> fail x
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Right t -> return $ CApp t e1' e2'
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newtype CProgram = CProgram [Def]
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lookupSig :: Ident -> Context -> Err Type
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lookupSig i (Ctx s _) = case Map.lookup i s of
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Nothing -> throwError $ "Undefined function: " <> show i
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Just x -> pure x
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data CType = TCInt | TCPol Ident | TCFun Type Type
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deriving (Eq, Ord, Show, Read)
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newtype CIdent = CIdent String
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deriving (Eq, Ord, Show, Read, Data.String.IsString)
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lookupSig :: Ident -> Env -> Err CType
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lookupSig i (Env m) = case Map.lookup i m of
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Nothing -> throwError $ "Unbound variable: " <> show i
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lookupEnv :: Ident -> Context -> Err Type
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lookupEnv i (Ctx _ []) = throwError $ "Unbound variable: " <> show i
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lookupEnv i (Ctx s (e:es)) = case Map.lookup i e of
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Nothing -> lookupEnv i (Ctx s es)
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Just x -> pure x
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applyType :: Type -> Type -> Err Type
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applyType (TFun (x:xs)) t = case t of
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(TFun ys) -> if ys `isPrefixOf` (x:xs)
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then return . TFun $ drop (length ys) (x:xs)
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else fail $ "Mismatched types, expected " <> show x <> " got " <> show TInt
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applyType t1 t2 = fail $ "Can not apply " <> show t1 <> " to " <> show t2
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class ExtractType a where
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getType :: a -> Type
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instance ExtractType CExp where
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getType = \case
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CId t _ -> t
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CInt t _ -> t
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CAdd t _ _ -> t
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CAbs t _ _ _ -> t
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CApp t _ _ -> t
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-- | λx : Int. x + 3 + 5
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customLambda1 :: Exp
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customLambda1 = EAbs (Ident "x") TInt (EAdd (EId (Ident "x")) (EAdd (EInt 3) (EInt 5)))
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customLambda2 :: Exp
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customLambda2 = EAbs (Ident "x") (TFun [TInt, TInt]) (EId (Ident "f"))
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-- | main : Int
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-- main = λx : Int. x + 3 + 5
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customPrg1 :: Program
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customPrg1 = Program [DExp (Ident "main") TInt (Ident "main") [] customLambda1]
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-- | main : Int -> Int
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-- main = λx : Int. x + 3 + 5
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customPrg2 :: Program
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customPrg2 = Program [DExp (Ident "main") (TFun [TInt, TInt]) (Ident "main") [] customLambda2]
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