Fixed precedence on '-'. Passed additional tests. Comments on bad.py. Updated worklog.

src/main/cup/chocopy/pa1/ChocoPy.cup

@@ -239,6 +239,7 @@ terminal String LBR;
 terminal String RBR;
 terminal String ARROW;
 terminal String IS;
+terminal String UMINUS;
 
 
 /* Returned by the lexer for erroneous tokens.  Since it does not appear in
@@ -282,6 +283,7 @@ precedence left NOT;
 precedence nonassoc EQUAL, NEQ, LT, GT, LEQ, GEQ, IS;
 precedence left PLUS, MINUS;
 precedence left MUL, DIV, MOD;
+precedence left UMINUS;
 precedence left DOT, COMMA, LBR, RBR;
 precedence right IF, ELSE;
 
@@ -295,8 +297,11 @@ start with program;
 
 /* program */
 program ::= program_head:d opt_stmt_list:s
-        {: RESULT = new Program(d.isEmpty() ? getLeft(s) : getLeft(d),
-                                sxright, d, s, errors);
+        {: 
+        ComplexSymbolFactory.Location left = d.isEmpty() ? getLeft(s) : getLeft(d);
+        if(left == null)
+            left = new ComplexSymbolFactory.Location(1,1);
+        RESULT = new Program(left, sxright, d, s, errors);
         :}
         ;
 
@@ -400,7 +405,7 @@ else_body ::= ELSE:el COLON block:b                                       {: RES
 simple_stmt ::= PASS:p                                        {: RESULT = null; :}
               | expr:e                                        {: RESULT = new ExprStmt(exleft, exright, e); :}
               | RETURN:r expr:e                               {: RESULT = new ReturnStmt(rxleft, exright, e); :}
-              | RETURN                                        {: RESULT = null; :}
+              | RETURN:r                                        {: RESULT = new ReturnStmt(rxleft, rxright, null); :}
               | opt_target:ot expr:e                          {: RESULT = new AssignStmt(getLeft(ot), exright, ot, e); :}
             ;
             
@@ -451,7 +456,7 @@ pexpr ::= identifier:id                                   {: RESULT = id; :}
         | 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); :}
+        | MINUS:m pexpr:p                                 {: RESULT = new UnaryExpr(mxleft, pxright, m, p); :} %prec UMINUS
         ;
         
 expr_list ::= expr:e                                      {: RESULT = single(e); :}