From 90a8f16e5f1d852f21fbbaf2b0631d348973152a Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Tue, 30 Aug 2022 23:21:50 +0100
Subject: Check undefined types

---
 src/Compiler.hs | 26 ++++++++++++++++++++++++++
 src/Error.hs    |  3 ++-
 2 files changed, 28 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/Compiler.hs b/src/Compiler.hs
index f788c11..785efab 100644
--- a/src/Compiler.hs
+++ b/src/Compiler.hs
@@ -3,6 +3,7 @@ module Compiler where
 import qualified Ast as A
 import Control.Monad.State
 import Data.Either (rights)
+import Data.Maybe (catMaybes, fromMaybe)
 import Env
 import Error
 import System.Environment (getEnv, getEnvironment)
@@ -77,6 +78,29 @@ typecheckReturn (Just value) fret = do
         else return $ Just $ "invalid return value\n     found: " ++ showMaybet r ++ "\n  expected: " ++ showMaybet fret
     Left _ -> return $ Nothing -- error resolving return value
 
+-- built-in types
+types = ["bool", "u8", "s8", "u16", "s16"]
+
+definedType :: A.Type -> Bool
+definedType (A.Type t) = t `elem` types
+definedType (A.FuncType ts r) =
+  all definedType ts && fromMaybe False (fmap definedType r)
+
+verifyFuncTypes :: String -> [A.FuncParam] -> Maybe A.Type -> SourcePos -> [Error]
+verifyFuncTypes ident params ret pos = do
+  ( catMaybes $
+      map
+        ( \(id, t, pos) ->
+            if not (definedType t)
+              then Just $ Error UndefinedType ("undefined type in \"" ++ id ++ "\"") pos
+              else Nothing
+        )
+        params
+    )
+    ++ if not (fromMaybe True (fmap definedType ret))
+      then [Error UndefinedType ("undefined return type in \"" ++ ident ++ "\"") pos]
+      else []
+
 compile :: A.Expr -> State CompState CompResult
 compile x = do
   case x of
@@ -90,6 +114,8 @@ compile x = do
     (A.Func ident params ret body priv anon pos) -> do
       -- current env
       (ev, errs) <- get
+      -- check for undefined types
+      (ev, errs) <- return $ (ev, (verifyFuncTypes ident params ret pos) ++ errs)
       -- updated with the function
       (ev, errs) <-
         return $ case addSymUniq ev (ident, ftype, pos) of
diff --git a/src/Error.hs b/src/Error.hs
index 40bb046..9aad85d 100644
--- a/src/Error.hs
+++ b/src/Error.hs
@@ -4,7 +4,7 @@ import Data.List (sort)
 import Text.Parsec (SourcePos, errorPos)
 import Text.Parsec.Error (ParseError, errorMessages, showErrorMessages)
 
-data ErrorType = GenericError | TypeError | UnexpectedReturn | AlreadyDefined | NonCallable | Undefined deriving (Show)
+data ErrorType = GenericError | TypeError | UnexpectedReturn | AlreadyDefined | NonCallable | Undefined | UndefinedType deriving (Show)
 
 instance Enum ErrorType where
   fromEnum GenericError = 0
@@ -13,6 +13,7 @@ instance Enum ErrorType where
   fromEnum AlreadyDefined = 3
   fromEnum NonCallable = 4
   fromEnum Undefined = 5
+  fromEnum UndefinedType = 6
   toEnum _ = error "toEnum is undefined for Error"
 
 data Error = Error ErrorType String SourcePos
-- 
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