Check undefined types

1 files changed, 26 insertions, 0 deletions

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