Re: Proposal: Determining whether a Bits instance is FiniteBits

This does seem like a strict improvement over the status quo.

Users can then conditionally get access to count(Trailing|Leading)Zeros by
refining the type information available to them using this combinator,
which offers a bunch of bit twiddling usecases.

-Edward

On Tue, May 18, 2021 at 9:30 AM Zemyla <[email protected]> wrote:

> Every Bits instance has to know that whether it's a FiniteBits
> instance as well, due to bitSizeMaybe. Therefore, it should also be
> able to tell a program that it is in fact a FiniteBits instance. There
> should be a function added to Data.Bits.Bits:
>
> withFiniteBits :: Bits a => a -> (FiniteBits a => r) -> r -> r
>
> The default should be withFiniteBits _ _ x = x, at least for the next
> several versions. bitSizeMaybe can be defined as
>
> bitSizeMaybe x = withFiniteBits x (Just (finiteBitSize x)) Nothing
>
> once everyone is on board with properly defining the value.
> _______________________________________________
> Libraries mailing list
> [email protected]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>

_______________________________________________
Libraries mailing list
[email protected]
http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries