Proposal: Small & focussed Type Tag library

[benhutchison]

I use Type Tags myself pretty often... I've used the Shapeless implementation at time, but in other projects, which don't otherwise depend on Shapeless, Ive defined them myself from scratch.

On several occasions in the last two years, Ive seen interest in a type-tag focussed library, eg:

• Cats Gitter May 16
• Cats Gitter June 16
• Cats issue 425

I want to propose (and I offer to maintain) a small typelevel lib that probably provides just 2 operations:

• Subtype tagging
• Newtype tagging

This isn't about defining new functionality or supporting advanced tagging use-cases, rather standardising operations people are already doing into a lightweight lib. As such, buy-in from typelevel user community would be important to project success.

Hence Im testing interest in the idea..?

[larsrh]

What about @julien-truffaut's newts library? https://github.com/julien-truffaut/newts

…

On 30 November 2017 23:05:56 CET, Ben Hutchison ***@***.***> wrote: I use Type Tags myself pretty often... I've used the Shapeless implementation at time, but in other projects, which don't otherwise depend on Shapeless, Ive defined them myself from scratch. On several occasions in the last two years, Ive seen interest in a type-tag focussed library, eg: - [Cats Gitter May 16](https://gitter.im/typelevel/cats?at=56d9f70ab0cc3f1b415024fd) - [Cats Gitter June 16](https://gitter.im/typelevel/cats?at=575b2a1e6092456f663308e3) - [Cats issue 425](typelevel/cats#425 (comment)) I want to propose (and I offer to maintain) a small typelevel lib that probably provides just 2 operations: - [Subtype tagging](https://github.com/milessabin/shapeless/blob/master/core/src/main/scala/shapeless/typeoperators.scala#L25) - [Newtype tagging](https://github.com/milessabin/shapeless/blob/master/core/src/main/scala/shapeless/typeoperators.scala#L36) This isn't about defining new functionality or supporting advanced tagging use-cases, rather standardising operations people are already doing into a lightweight lib. As such, buy-in from typelevel user community would be important to project success. Hence Im testing interest in the idea..? -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: #87

[benhutchison]

I wasn't aware of newts actually. That seems to address much of what I had in mind. There are use cases where subtype tags are needed, eg attaching additional info to Array[Double] without losing the underlying type. I didn't see support for that in newts?

…

-Ben

On Fri, Dec 1, 2017 at 9:14 AM, Lars Hupel ***@***.***> wrote: What about @julien-truffaut's newts library? https://github.com/julien- truffaut/newts On 30 November 2017 23:05:56 CET, Ben Hutchison ***@***.***> wrote: >I use Type Tags myself pretty often... I've used the Shapeless >implementation at time, but in other projects, which don't otherwise >depend on Shapeless, Ive defined them myself from scratch. > >On several occasions in the last two years, Ive seen interest in a >type-tag focussed library, eg: >- [Cats Gitter May >16](https://gitter.im/typelevel/cats?at=56d9f70ab0cc3f1b415024fd) >- [Cats Gitter June >16](https://gitter.im/typelevel/cats?at=575b2a1e6092456f663308e3) >- [Cats issue >425](typelevel/cats#425 (comment)) > >I want to propose (and I offer to maintain) a small typelevel lib that >probably provides just 2 operations: >- [Subtype >tagging](https://github.com/milessabin/shapeless/blob/ master/core/src/main/scala/shapeless/typeoperators.scala#L25) >- [Newtype >tagging](https://github.com/milessabin/shapeless/blob/ master/core/src/main/scala/shapeless/typeoperators.scala#L36) > >This isn't about defining new functionality or supporting advanced >tagging use-cases, rather standardising operations people are already >doing into a lightweight lib. As such, buy-in from typelevel user >community would be important to project success. > >Hence Im testing interest in the idea..? > >-- >You are receiving this because you are subscribed to this thread. >Reply to this email directly or view it on GitHub: >#87 — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#87 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAF05FsEHXrjxSPYTaQvnG7x7I9MHzOcks5s7yjbgaJpZM4QxRe5> .

[benhutchison]

Also (belatedly!) just noticed discussion at typelevel/cats#1800 that seemed to reach leaving tags outside cats as at 1.0