fastsum
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Requiring Show1 for Show, Eq1 for Eq, etc., is inconvenient
Once upon a time, fastsum
had separate Apply
and Apply1
typeclasses s.t. we could use Apply
for Show
and Apply1
for Functor
. We eventually got rid of the former because compile times were already far too high, and instead used Show1
to provide our Show
instance.
However, while it’s easy to derive Show
instances, Show1
is not derivable, so you have to do a bunch of extra work just to show your Sum
s.