[Haskell-cafe] ATs vs FDs

[Stephen Tetley]

On 14 August 2010 11:19, Andrew Coppin <andrewcoppin at btinternet.com> wrote:
> As I understand it, ATs were invented because FDs are "evil" and must never
> be used ever for any purpose. However, it doesn't seem to be possible to use
> ATs to do the same things that FDs can do.
>

You might want to read the "Language and Program Design for Functional
Dependencies" paper by Mark P. Jones and Iavor Diatchki.

In some situations fundeps are much cleaner than type funs, and
cleanliness is virtuous surely?