[Haskell-cafe] How to make boolean logic with IO Monad more expressive?

[Magicloud Magiclouds]

Cool. Thanks.

On Mon, May 27, 2019 at 5:10 PM Viktor Dukhovni <ietf-dane at dukhovni.org> wrote:
>
>
>
> > On May 27, 2019, at 1:07 AM, Magicloud Magiclouds <magicloud.magiclouds at gmail.com> wrote:
> >
> > ```
> > status <- ioOperation -- IO-ed anyway
> > return $ pureComputing || (status && pure2)
> > ```
>
> With two helpers:
>
>   (<&&>) :: IO Bool -> IO Bool -> IO Bool
>   (<&&>) ma mb = ma >>= (\a -> if not a then return False else mb)
>
>   (<||>) :: IO Bool -> IO Bool -> IO Bool
>   (<||>) ma mb = ma >>= (\a -> if a then return True else mb)
>
> you'd write:
>
>   pure preComputing <||> (ioOperation <&&> pure pure2)
>
> You could even define suitable fixity to make <&&> have higher
> precedence than <||> and not need any parentheses.
>
> --
>         Viktor.
>
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