> :t Just True
Just True :: Maybe Bool
> :t Left True
Left True :: Either Bool b
> :t Right False
Right False :: Either a Bool
What am I being told here? It seems
data Maybe a = Just a
| Nothing
data Either a b = Left a
| Right b
are both straightforward parameterized types, but Maybe doesn't give me a type parameter back, while Either does, and in different order, different names (a becomes b; b becomes a) depending on which variable I invoke. What deeper lore am I not seeing here?
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⨽
Lawrence Bottorff
Grand Marais, MN, USA