[Haskell-cafe] OverloadedStrings, but with compile-time invariants

[Brandon Allbery]

Might https://hackage.haskell.org/package/validated-literals be of interest?

On Fri, Dec 8, 2023 at 2:13 PM Viktor Dukhovni <ietf-dane at dukhovni.org>
wrote:

> On Fri, Dec 08, 2023 at 04:50:58PM +0100, Max Ulidtko wrote:
>
> > And overall, to zoom out of "XY Problem" pitfalls: am I missing a neater
> way
> > to have "partial" IsString instances, those that can reject some
> literals at
> > compile-time?
> >
> > Having this code work is the goal:
> >
> > text1, text2 :: NonEmptyText
> > text1 = "hello, types"
> > text2 = "" -- compile error
>
> Is at TH splice too cumbersome?
>
>     text1, text2 :: NonEmptyText
>     text1 = $$(neTxt "hello, types")
>     text = $$(neTxt "") -- compile error
>
> I am validating DNS domain name literals at compile time, where checks
> include full DNS syntax validation with no empty labels, no labels
> longer than 63 bytes, and overall wire length at most 255 bytes.
>
>
> https://github.com/dnsbase/dnsbase/blob/548270f2e575949592ca3f1e40c58edc450bd0c3/internal/Net/DNSBase/Internal/Domain.hs#L249-L267
>
> --
>     Viktor.
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-- 
brandon s allbery kf8nh
allbery.b at gmail.com
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