Hi, Am Mittwoch, den 14.02.2018, 09:47 -0500 schrieb Mario Blažević:
I understand it's hard to grep, but can you guess how many of those 40-80 uses of (<>) with the union meaning actually depend on the left-biased semantics? I've looked at my code, and it turns out that wherever this operation appears, the two maps are guaranteed to have distinct keys.
does this indicate the need for disjointUnion :: IntMap a -> IntMap a -> IntMap a that throws an error when the maps are not disjoint? (run-time error only, because we are not doing theorem proving here…) One can get the effect with unionWith (error "not disjoint) of course (and I have done so), but having `disjointUnion` in the API might remind people that they have to think about which variant they want. Cheers, Joachim -- Joachim Breitner mail@joachim-breitner.de http://www.joachim-breitner.de/