[Haskell-cafe] [ANN] isbn - ISBN Validation and Manipulation

[Carter Schonwald]

cool! Thanks for sharing!
(i mean, who doesn't like to read a good book!)

Question: would it be worth considering  internally having the digits be
stored as half bytes for space usage? eg ISBN10 -> use ~ 5 bytes, and
ISBN13 be ~ 7 bytes  (this could be within a word64 as a tiny 8 slot array,
OR  or any sort of vector/array datatype)? (or instead of a decimal binary
rep, pack it into a word64 as the number itself for either?) Granted this
would complicate some of the internals engineering a teeny bit

it looks like, in the current code, if there's  no hyphens, it'll keep the
input text value as the internal rep, *which can cause space leaks* if it's
a slice of a much larger text input you otherwise do not intend to retain.
When it generates its own text string, well...  the text package uses utf16
(aka 2 bytes per character for valid ascii) as the internal rep, so the
buffer representation  will occupy 10 * 2 bytes  or 13* 2bytes, so 20-26
bytes within the buffer, ignoring the extra word or two of indexing/offsets!

point being ... it seems like could embed them (with a teeny bit of work)
as follows

data ISBN =
     IsIBSN10 ISBN10
     | isISBN13 ISBN13

newtype ISBN10 = ISBN10 Word64
newtype ISBN13 = ISBN13 Word64

and then i'd probably be inclined to do use Data.Bits and do the "word 64
as a 16 slot array of  word4's," which would also support the base 11 digit
at the end encoding constraint, since word4 == base 16 :)
then a teeny bit of work to do the right "right" ords and shows etc on this
rep etc

i hope the design i'm pointing out makes sense for you (and if i'm not
being clear, please holler and i'll try to help)

and again, thanks for sharing this!
-Carter


On Wed, Jul 29, 2020 at 1:39 PM Christian Charukiewicz via Haskell-Cafe <
haskell-cafe at haskell.org> wrote:

> Hello Haskell Cafe,
>
> I wanted to share my first ever Haskell package: isbn
>
> https://hackage.haskell.org/package/isbn
>
> The package is motivated by my need to validate ISBNs (the unique
> identifier associated with every book published since 1970) in a Haskell
> application I am building. I published isbn as a back in May but yesterday
> I made some improvements the API and I think it is now ready to share as
> v1.1.0.0.
>
> I have been using Haskell commercially for a few years, and have made
> several contributions to various packages, but as mentioned, this is my
> first time authoring and publishing a package. If anyone has any feedback,
> I would be happy to hear it.
>
> Thank you,
>
> Christian Charukiewicz
> _______________________________________________
> Haskell-Cafe mailing list
> To (un)subscribe, modify options or view archives go to:
> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
> Only members subscribed via the mailman list are allowed to post.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/haskell-cafe/attachments/20200730/ff422ec6/attachment.html>