From: pimjager <pim@pimjager.nl>
Date: Thu, 14 Apr 2016 09:21:29 +0000 (+0200)
Subject: working on presentation
X-Git-Url: https://git.martlubbers.net/?a=commitdiff_plain;h=158fb0cf298aaae42c8460f92bb7d797d5def9bd;p=cc1516.git

working on presentation
---

diff --git a/deliverables/p2/p2.tex b/deliverables/p2/p2.tex
index 09d75d2..a3fca20 100644
--- a/deliverables/p2/p2.tex
+++ b/deliverables/p2/p2.tex
@@ -130,7 +130,6 @@ flop(n, l) :: Int -> [Int] -> Bool {
 	\begin{itemize}
 		\item Mutual recursion is allowed and type checked, however inference is
 		not complete.
-		\pause
 		\begin{CleanCode}
 flip(n, l) {
   if( n <= 0 ) {return l;} 
@@ -165,6 +164,36 @@ flop(n, l) :: Int -> [Int] -> HSWdn {
 	\end{itemize}
 \end{frame}
 
+\begin{frame}[fragile]
+	\frametitle{But wait, there is more!}
+	\framesubtitle{Trouble that is}
+	\begin{itemize}
+		\item Polymorphism is not working great either.
+		\begin{CleanCode}
+id(x) :: a -> a {
+    return x;    
+}
+		\end{CleanCode}
+		\pause
+		\item Is typed fun, but when we introduce: 
+		\begin{CleanCode}
+var x = id(5);
+var y = id(True);
+		\end{CleanCode}
+		\pause
+		\begin{CleanCode}
+2:12 SemError: Cannot unify types. Expected: Int. Given: Bool
+		\end{CleanCode}
+	\end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+	\frametitle{But wait, there is more!}
+	\framesubtitle{Trouble that is}
+	
+	\begin
+\end{frame}
+
 % - Can functions that are defined later in a file call earlier defined functions?
 % - Can local variables be defined in terms of other local variables?
 % - How do you deal with assignments?
diff --git a/sem.icl b/sem.icl
index 3438810..06200b1 100644
--- a/sem.icl
+++ b/sem.icl
@@ -59,25 +59,19 @@ semFunDecl fd=:(FunDecl p f args mt vds stmts) =
  	matchFunctions args ft >>= \tres->
     mapM semVarDecl vds >>= \newvds->
     mapM (checkStmt tres) stmts >>= \newstmts->
-	inferReturnType stmts >>= \returntype->
 	case mt of
-		Nothing = reconstructType args tres
+		Nothing = inferReturnType stmts
+			>>= \returntype->reconstructType args tres 
 			>>= \ftype->restoreGamma gamma 
 			>>| putIdent f ftype >>| pure (
 			FunDecl p f args (Just ftype) newvds newstmts)
-		Just t = restoreGamma gamma >>| updateFunType t returntype
-			>>= \tt-> pure (FunDecl p f args (Just tt) newvds newstmts) 
-
-updateFunType :: Type Type -> Env Type
-updateFunType t1 t2 = unify t1 t2
-updateFunType (t1 ->> t2) t3 = t1 ->> (updateFunType t2 t3)
+		Just t = restoreGamma gamma 
+			>>| pure (FunDecl p f args mt newvds newstmts) 
 
 inferReturnType :: [Stmt] -> Env Type
 inferReturnType [] = pure VoidType
-inferReturnType [ReturnStmt (Just t):rest] = typeExpr t 
-	>>= \tx->inferReturnType rest >>= \ty->unify tx ty
-inferReturnType [ReturnStmt _:rest] = 
-	inferReturnType rest >>= \tx-> unify VoidType tx
+inferReturnType [ReturnStmt (Just t):rest] = typeExpr t
+inferReturnType [ReturnStmt _:rest] = pure VoidType
 inferReturnType [_:rest] = inferReturnType rest
 
 reconstructType :: [String] Type -> Env Type
@@ -206,8 +200,6 @@ instance unify Type where
     unify (ListType t1) (ListType t2) = unify t1 t2 >>| (pure $ ListType t1)
     unify (ta1 ->> ta2) (tb1 ->> tb2) = unify ta1 tb1 >>= \ta-> unify ta2 tb2 
         >>= \tb-> pure (ta ->> tb)
-    unify VoidType t = pure t
-    unify t VoidType = pure t
     unify VoidType VoidType = pure VoidType
 	unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2