Another typing question

[oleg@pobox.com]

> Is there any way to parametrize a type by a value, rather than another
> type?

I believe the following web page answers your question:

	http://pobox.com/~oleg/ftp/Haskell/number-parameterized-types.html 

It uses parameterization by decimal numbers -- which seem more
natural to read.

> It would be interesting to know if/how you could, e.g., define a
> concatenation function with a type like

Yes, you can -- and the page referenced above does that.