[Haskell-cafe] Best way to return Bool based on a successful pattern match?

Adam Bergmark adam at bergmark.nl
Mon Jul 13 13:24:40 UTC 2015

Perhaps this is of interest to you,


On Mon, Jul 13, 2015 at 3:04 PM, Nikolay Amiantov <ab at fmap.me> wrote:

> Yes, for standard data types like Either or Maybe the best way is to use
> library-defined functions -- I was more interested in a way to check for
> any given pattern, which would look nicer than a custom defined function
> or a LambdaCase. An example use case:
> partition (\case MyPat -> True; _ -> False)
> Anyway using lens for this is already very readable and concise, albeit
> needs makePrisms/Lens and stuff.
> On 07/13/2015 03:02 PM, Nikita Karetnikov wrote:
> > Looking at the instances defined for Bool and Either, I don't think
> > there's a higher level way of doing it.  But even if there's one, it'll
> > probably be more obscure than isLeft, which is in base since
> >
> --
> Nikolay.
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