this is a possibility. i think the idea of using a function property could be used in a simpler way, though. `doctest` could simply have a `doctest.options` object, with default values, overridden by command line arguments. i have to see the code again. if we want to have global options within the module like in this pull request, `doctest` could simply have a `doctest.setOptions(o)` method. i'd like to keep it simple. it may look weird to you, but generally i try to avoid using classes in javascript. anyway i don't see drawbacks in your idea, could be fine for me