A much nicer version of this is the Common Lisp condition system. Roughly the way it works is that in addition to being able to raise exceptions, a procedure c

A much nicer version of this is the Common Lisp condition system. Roughly the way it works is that in addition to being able to raise exceptions, a procedure can ask a condition handler how to proceed. Basically, the condition handlers are dynamically scoped like a try/catch, and the conditions can be finer-grained than a catch-all Error (though to be somewhat fair to Visual Basic, you could also "On Error GoTo handler_label"). Here's how it might look in Python: try: f = open("foo.txt") s = f.read() condition FileNotExists as c: handle UseStream(io.StringIO("")) where when open fails to find a file, Python will look for the first FileNotExists condition handler, pass it a FileNotExists condition object, and then the handler can choose to handle the condition. On the open side, it could be something like this: def open(filename): restartable: ... low-level stuff to open the file ... if failed: signal FileNotExists(filename) ... restart UseStream as r: return r.stream