diff --git a/src/main/cup/chocopy/pa1/ChocoPy.cup b/src/main/cup/chocopy/pa1/ChocoPy.cup
index 13e324c..bb26a36 100644
--- a/src/main/cup/chocopy/pa1/ChocoPy.cup
+++ b/src/main/cup/chocopy/pa1/ChocoPy.cup
@@ -268,7 +268,7 @@ precedence nonassoc EQUAL, NEQ, LT, GT, LEQ, GEQ, IS;
 precedence left PLUS, MINUS;
 precedence left MUL, DIV, MOD;
 precedence left DOT, COMMA, LBR, RBR;
-precedence left IF, ELSE;
+precedence right IF, ELSE;
 
 /* The start symbol. */
 start with program;
@@ -315,12 +315,12 @@ class_body_defs ::= class_body_defs:defs var_def:vd       {: RESULT = combine(de
 
 
 /* fun_def */
-fun_def ::= DEF:def identifier:id LPAR typed_vars:params RPAR ret_type:rt COLON NEWLINE INDENT fun_body_decs:fbd stmt_list:sl DEDENT        
-            {: RESULT = new FuncDef(defxleft, getRight(sl), id, params, rt, fbd, sl); :}
+fun_def ::= DEF:def identifier:id LPAR typed_vars:params RPAR ret_type:rt COLON:col NEWLINE INDENT fun_body_decs:fbd stmt_list:sl DEDENT       
+            {: TypeAnnotation _rt = rt;if(rt.getLocation()[0] == -2) _rt = new ClassType( colxright, colxright, "<None>");RESULT = new FuncDef(defxleft, getRight(sl), id, params, _rt, fbd, sl); :}
             ;
 
 ret_type ::= ARROW type:t     {: RESULT= t; :}
-          |                   {: RESULT= null; :}
+          |                   {: RESULT= new ClassType(new ComplexSymbolFactory.Location(-2,-1), new ComplexSymbolFactory.Location(-1,-1),"<None>"); :}
           ;
 
 typed_vars ::= typed_var:tv                                 {: RESULT= single(tv); :}
@@ -427,13 +427,17 @@ pexpr ::= identifier:id                                   {: RESULT = id; :}
         | index_expr:i                                    {: RESULT = i; :}
         | member_expr:m LPAR expr_list:l RPAR:rpar        {: RESULT = new MethodCallExpr(mxleft, rparxright, m, l); :}
         | identifier:id LPAR expr_list:l RPAR:rpar        {: RESULT = new CallExpr(idxleft, rparxright, id, l); :}
-        | pexpr:p1 bin_op:bo pexpr:p2                     {: RESULT = new BinaryExpr(p1xleft, p2xright, p1, bo.value, p2); :}
+        | pexpr:p1 PLUS:bo pexpr:p2                     {: RESULT = new BinaryExpr(p1xleft, p2xright, p1, bo, p2); :}
+        | pexpr:p1 MINUS:bo pexpr:p2                     {: RESULT = new BinaryExpr(p1xleft, p2xright, p1, bo, p2); :}
+        | pexpr:p1 MUL:bo pexpr:p2                     {: RESULT = new BinaryExpr(p1xleft, p2xright, p1, bo, p2); :}
+        | pexpr:p1 DIV:bo pexpr:p2                     {: RESULT = new BinaryExpr(p1xleft, p2xright, p1, bo, p2); :}
+        | pexpr:p1 MOD:bo pexpr:p2                     {: RESULT = new BinaryExpr(p1xleft, p2xright, p1, bo, p2); :}
         | MINUS:m pexpr:p                                 {: RESULT = new UnaryExpr(mxleft, pxright, m, p); :}
         ;
         
 expr_list ::= expr:e                                      {: RESULT = single(e); :}
             | expr_list:el COMMA expr:e                   {: RESULT = combine(el, e); :}
-            |                                             {: RESULT = null; :}
+            |                                             {: RESULT = new ArrayList<Expr>(); :}
             ;