Reasons behind the "one instance per type" limitation

Iavor S. Diatchki
Tue, 9 Oct 2001 09:28:03 -0700


> Why aren't instance declarations handled by the module system like
> every other symbol, so that a module can decide when to import an
> instance declaration and when to export it? Are there technical
> difficulties with this approach?

i beleive the reason is that instances don't  have names and the
module system deals with names.  on the other hand i don't think
this is a very good reason and completely agree with you that
it is a problem.  i think some work is being done on introducing
named instances to Hasekll (there was a paper in the Haskell workshop
i think).


| Iavor S. Diatchki, Ph.D. student               | 
| Department of Computer Science and Engineering |
| School of OGI at OHSU                          |
|               |