Run examples embedded in documentation
Save that to 'add7.m'. Now you can say 'doctest add7' and it will run
'add7(3)' and make sure that it gets back 'ans = 10'.
+ If the output of some function will change each time you call it, for
+ instance if it includes a random number, you can put *** (three
+ asterisks) where the changing element should be. This acts as a
+ wildcard, and will match anything.
because I haven't found a good way to mark these subsequent lines as
part-of-the-source-code rather than part-of-the-result.