[m-users.] Adding impurity to Mercury code: Backtracking in IO states

[Tomas By]

On Sun, June 28, 2015 19:15, Left Right wrote:
> @Tomas, is "unique" similar to Prolog's atom(X) when it's used to
> format a string


I don't think so.

It is somewhat similar to `difference lists' in that you have a pair of
them, there is an implied sequence of values, but you only use one value
at any particular point in time.

/Tomas