Another typing question

[Konrad Hinsen]

Is there any way to parametrize a type by a value, rather than another ty=
pe?=20
What I would like to do is to define "list of length 3" and "list of leng=
th=20
4" as separate parametrization of the same type, such that I could write=20
functions that accept lists (under my new typename) of any length as long=
 as=20
parameters have the same length. The goal is to remove the need for runti=
me=20
checks all over the code.

Konrad.