Fix newline handling

parser.y

@@ -107,11 +107,16 @@ stmts
     | stmt { $$ = $1; }
     ;
 
+newlines
+    : newlines NEWLINE
+    |
+    ;
+
 stmt
-    : expr NEWLINE { $$ = concatenate($1, ";"); }
-    | if { $$ = $1; }
-    | while { $$ = $1; }
-    | BREAK NEWLINE { $$ = new std::string("break;"); }
+    : expr NEWLINE newlines { $$ = concatenate($1, ";"); }
+    | if newlines { $$ = $1; }
+    | while newlines { $$ = $1; }
+    | BREAK newlines { $$ = new std::string("break;"); }
     ;
 
 expr