All Programming Languages are Wrong (2018)

Re:All Programming Languages are Wrong (2018) by karmakaze on Wednesday February 12, 2020 @04:53AM (#22307459)

I rather like that, `if condition` is a 0/1 iteration with no input. flatMap can return empty, what should map return when run on false, None?

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Re:All Programming Languages are Wrong (2018) by mrgriffin on Wednesday February 12, 2020 @12:44PM (#22310865)

I'd probably think of Bool as being isomorphic to Maybe (), which would mean your map implementation looks a bit like:

    map :: Bool -> (() -> b) -> Maybe b
    map True f = Just (f ())
    map False _ = Nothing

Or, in Haskell because you've got laziness you could go with:

    map :: Bool -> b -> Maybe b

Which already exists as a combination of Control.Monad.guard and Data.Functor.(<$).

    map tf b = b <$ guard tf

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