Hi folks,

Is there any way to flag an Array as immutable, so I can use it
as a key in a hash table without worrying about it changing?  This
is what the "tuple" in python is for, and there I find it useful.

This comes up, since every now and then I want to simply use [x,y,z]
points as hash keys, and I would like to have some assurance that
this will not cause problems.

Thanks,

--Johann