In OOP, static scope means the scope is linked to the class, and instance scope is linked to a specific instance of the class.
Some languages support static locals, which allow a value to be retained from one call of a function to another, however still in static scope.
As you might conclude from some other posts by me here, you can tell I'm a big fan of encapsulation.
Sometimes I use a certain instance variable within a class, only within one method. E.g. a flag indicating whether a certain method has already been called. My convention (following good standards) is to place these variables right before the function, close to their usage. Ideally, I would be able to place them within the function scope. Following the naming scheme of static locals, let's call this hypothetical scope function locals.
Darien reworded this very clearly in a comment:
Ah, so what you really want is something beyond even private protection, which is so closely protected that it is only visible to a single method within a single instance.
Now I know you could say, following the Single Responsibility Principle, this method and the associated variables should most likely be split into a separate class. To verify this - and I challenge you to do the same - I looked into some random code files and quickly found source files (even < 100 lines) where such a 'function local' could be used.
Actually, C# offers a solution to this for one common scenario out of the box. Auto-implemented properties hide the backing field.
This idea might be far-fetched, but somehow I feel it would make sense. Does anybody know of any language which supports this?