+/// parser happily accepted various junk like 'x^2()+1'
+static int check4(std::ostream& err_str)
+{
+ const std::string junk("x^2()+1");
+ parser reader;
+ ex e;
+ try {
+ e = reader(junk);
+ err_str << "parser accepts junk: \"" << junk << "\"" << std::endl;
+ return 1;
+ } catch (parse_error& err) {
+ // Ok, parser rejects the nonsense.
+ return 0;
+ }
+}
+