[Haskell-cafe] What is Data.Vec.DataFamily.SpineStrict.Pigeonhole and why is it following me?

[Adam Gundry]

> This <https://hackage.haskell.org/package/vec-0.4/docs/Data-Vec-DataFamily-SpineStrict-Pigeonhole.html> in Hackage is something a rank amateur like me can't fathom. ... Anyone know how I can figure this mystery out, like at least find the author or someone that knows something about this?

Regarding this part of the question, if you click the "Contents" link at
the top of the page to which you linked, it will take you to the package
main page (https://hackage.haskell.org/package/vec-0.4). The column on
the right gives the author's name and email address, and a link to the
source repository (https://github.com/phadej/vec).

The main column on that page gives the package description, which may
help explain and motivate what is going on a bit more. In this case it
also links to some relevant papers.

Hope this helps,

Adam


On 29/11/2021 04:59, David Feuer wrote:
> No, this seems to have nothing to do with the pigeonhole principle. It
> seems to be about the sizes of length-indexed vectors. The "pigeonhole
> size" is just the vector length, available at the type level. This all
> seems to be about matching up vectors to representable functors. So it
> would match up
> 
>     data Foo a = Foo a a a a
> 
> to the type of vectors of length 4, giving functions to convert between
> them. I'm ... not exactly sure what purpose this serves.
> 
> On Sun, Nov 28, 2021, 11:07 PM Galaxy Being <borgauf at gmail.com
> <mailto:borgauf at gmail.com>> wrote:
> 
>     Spam detection software, running on the system "mail.haskell.org
>     <http://mail.haskell.org>", has
>     identified this incoming email as possible spam.  The original message
>     has been attached to this so you can view it (if it isn't spam) or label
>     similar future email.  If you have any questions, see
>     @@CONTACT_ADDRESS@@ for details.
> 
>     Content preview:  This
>     <https://hackage.haskell.org/package/vec-0.4/docs/Data-Vec-DataFamily-SpineStrict-Pigeonhole.html
>     <https://hackage.haskell.org/package/vec-0.4/docs/Data-Vec-DataFamily-SpineStrict-Pigeonhole.html>>
>        in Hackage is something a rank amateur like me can't fathom. I
>     just hit a
>        chapter in a book that dives into the Pigeonhole Principle. Is
>     this the "accompanying
>        Haskell Wundercode" for the math world's PHP? I know PHP is a big
>     deal in
>        math. I don't see an "author," and I see no documentation. Anyone
>     know how
>        I can figure this mystery out, like at least find the author or
>     someone that
>        knows something about this? [...]
> 
>     Content analysis details:   (5.0 points, 5.0 required)
> 
>      pts rule name              description
>     ---- ----------------------
>     --------------------------------------------------
>      0.0 FREEMAIL_FROM          Sender email is commonly abused enduser
>     mail provider
>                                 (borgauf[at]gmail.com <http://gmail.com>)
>     -0.0 SPF_PASS               SPF: sender matches SPF record
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> 
>     ---------- Forwarded message ----------
>     From: Galaxy Being <borgauf at gmail.com <mailto:borgauf at gmail.com>>
>     To: haskell-cafe <haskell-cafe at haskell.org
>     <mailto:haskell-cafe at haskell.org>>
>     Cc: 
>     Bcc: 
>     Date: Sun, 28 Nov 2021 22:05:44 -0600
>     Subject: What is Data.Vec.DataFamily.SpineStrict.Pigeonhole and why
>     is it following me?
>     This
>     <https://hackage.haskell.org/package/vec-0.4/docs/Data-Vec-DataFamily-SpineStrict-Pigeonhole.html>
>     in Hackage is something a rank amateur like me can't fathom. I just
>     hit a chapter in a book that dives into the Pigeonhole Principle. Is
>     this the "accompanying Haskell Wundercode" for the math world's PHP?
>     I know PHP is a big deal in math. I don't see an "author," and I see
>     no documentation. Anyone know how I can figure this mystery
>     out, like at least find the author or someone that knows something
>     about this?
> 
>     -- 
>     ⨽
>     Lawrence Bottorff
>     Grand Marais, MN, USA
>     borgauf at gmail.com <mailto:borgauf at gmail.com>



-- 
Adam Gundry, Haskell Consultant
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