Matt T Heffron asked:
Just how would you define "negative number of keywords" ??
I expected this question, but hoped that you would guess how. Of course.
The concept should be related to the idea of a "custom keyword". Are you getting the idea already?
I don't want to discuss what a "custom keyword" may mean, it could be probably introduced in different ways. It's important to understand that it should not be a name of the type, object, method, nothing like a usual name defined by a developer, it should really be a "keyword". It should be defined by the user, extend the language, and be usable since that moment of time. For now, let's just assume that such concept is introduced.
So, in particular, if some language, originally, before customization, has zero keywords, it means the following: the user can customize it, for example, by adding one keyword which can further be used. Now, we can devise a language that has, say, −5 keywords. This would be the language with the following property: to customize the language to have just one usable keyword, the customer will need to add 6 keywords; to get 5 usable keywords, the customer would need to add 10, and so on.
Provided the concept of the "custom keyword" is already available, the implementation of the language with negative number of keywords would be really quite simple. :-)
—SA