Message9192

It's easy to add a check, which I'll do as a first step in the constructor(s).

The cost of doing this check grates a little.

When one steps through the example, a notable feature is that the construction happens twice, once by calling __str__(), which wraps the result of toString() in a PyString, and once by shelling that PyString to wrap its implementation string again. A simple fix ends up checking the String a second time. And it's not the only place where we shill check strings that we can tell are clean a priori. I'll look for ways to avoid that where it might be frequent, as a second step.

I note this is tagged 2.5. I'll fix in the tip. Do we intend to back-port it?