[m-dev.] Adding Loops to Mercury
jfischer at opturion.com
Fri Jan 10 16:21:44 AEDT 2014
On Thu, 9 Jan 2014, Peter Schachte wrote:
> On 08/01/14 23:58, Mark Brown wrote:
>> Currently in Mercury I can define an instance for foldable(map(K, V),
>> pair(K, V)), but not foldable(list(T), T) or foldable(set(T), T).
> That's weird. I can't see why the former would be workable if the
> latter two are not.
Because the latter two instances are not currently valid Mercury.
Mercury currently requires that arguments in instance heads "must be
either a type with no arguments, or a polymorphic type whose arguments
are all type variables".
More information about the developers