--- loncom/homework/math_parser/ENode.pm	2015/06/30 17:42:14	1.3
+++ loncom/homework/math_parser/ENode.pm	2017/01/19 19:24:57	1.4
@@ -836,9 +836,14 @@ sub toTeX {
                         return "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX().
                         "}".$c1->toTeX();
                     } else {
-                        return "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX().
-                        (($c4->value eq "plus") ? "+" : "-").
-                        "}".$c1->toTeX();
+                        my $s = "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX();
+                        if ($c4->value eq "plus") {
+                            $s .= "+";
+                        } elsif ($c4->value eq "minus") {
+                            $s .= "-";
+                        }
+                        $s .= "}".$c1->toTeX();
+                        return $s;
                     }
                 }
                 when ("binomial") {