Certainly, it may be possible to give this functionality to lists tagged with the type 'alist. But then what would it do when I want to find the zeroth element of an alist where 0 is a key? You could have it just default to one or the other, but then I'd just end up ignoring whichever indexing operation it doesn't default to and using a differently-named function all the time for the other type of indexing in general alist code. In which case, what's the point of overloading the function in the first place?
No contest, my idea is half-baked. I had in mind symbols as keys, where you could define reasonable semantics. I'm still bugged by the lack of symmetry: For any X with which it makes some sense at all, (X ...) seems to work. Constants, hashes, strings, lists... even lambdas ;-)
Obviously the issue is that alists are only a convention.
