Re: Proposal: change the Bits instance for Bool to align with other basic types and support branchless calculations

I don't think this newtype idea is likely to work out so beautifully. The main problem is that real code is likely to do a lot of mixing and matching of short-circuit and non-short-circuit code. The newtype concept requires a lot of wrapping and unwrapping to express that, and trying out different approaches to find the fastest leads to a lot of complicated wrapper rearrangement. On Mon, Sep 29, 2014 at 12:54 PM, Brandon Allbery wrote:

On Mon, Sep 29, 2014 at 12:50 PM, Anthony Cowley wrote:

...

Yes, the differing opinions make the newtype introduction appealing, but if Bits is eventually made lazier to support generalized short-circuiting, will this then be a wart there? I've really liked a lot of the points I've seen from both sides of this debate, so it'd be great to navigate the branchy vs branchless crossroads with a bit of style.

I think the point is that this exactly addresses that: people who want the spine strictness of the existing Bits instances get it for Bool via the newtype and corresponding strict Bits instance (and maybe other instances), people who want laziness get it via Bool --- and this also advances the cause of generalizing existing Bool-related things, since the next obvious thing to do is make it possible to use && and || on a typeclass instead of hardcoded for Bool, so they can be extended to Bit.

-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

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