Re: [Haskell-cafe] Bundle patterns with type aliases
Here's a class example: class (MFoldable t, Monoid t) => Sequence t where singleton :: Elem t -> t One might wish to write pattern synonyms for viewing the ends of a sequence, like the ones in Data.Sequence, and bundle them with this class. On Thu, Sep 16, 2021, 2:22 PM Carter Schonwald wrote: > These are great ideas! Could you please create a ghc tracker ticket with a > tiny examples or two? > > There may be specific technical reasons we might not be able to do so for > type synonyms in ghc, but I don’t see any obvious barriers in the case of > David’s excellent idea, I’ve def seen lots of great code out there where > you’d really want either associated pattern synonyms or to bundle pattern > synonyms with the exported public interface for a type class. > > I’m sure there’s some devil in the details but these sound lovely. Step > -1 is making up 1-2 toy examples and explaining what and why you want it on > a ghc ticket! > > On Wed, Sep 8, 2021 at 1:25 PM David Feuer wrote: > >> I would like that, along with the ability to bundle patterns with classes. >> >> On Wed, Sep 8, 2021, 1:13 PM Keith wrote: >> >>> Is there currently a way to 'bundle' a pattern with a type alias? And if >>> not, could that capability be added to the PatternSynonyms GHC extension? >>> (Is this the right place to ask, or should I be asking a GHC list?) >>> >>> --Keith >>> Sent from my phone with K-9 Mail. >>> ___ >>> 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. >> >> ___ >> 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. > > ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
Re: [Haskell-cafe] Bundle patterns with type aliases
Here's an example: pattern State :: (s -> (a, s)) -> State s a pattern State f <- (coerce . runStateT -> f) where State = state This would be very nice to bundle with the State type synonym. On Thu, Sep 16, 2021, 2:22 PM Carter Schonwald wrote: > These are great ideas! Could you please create a ghc tracker ticket with a > tiny examples or two? > > There may be specific technical reasons we might not be able to do so for > type synonyms in ghc, but I don’t see any obvious barriers in the case of > David’s excellent idea, I’ve def seen lots of great code out there where > you’d really want either associated pattern synonyms or to bundle pattern > synonyms with the exported public interface for a type class. > > I’m sure there’s some devil in the details but these sound lovely. Step > -1 is making up 1-2 toy examples and explaining what and why you want it on > a ghc ticket! > > On Wed, Sep 8, 2021 at 1:25 PM David Feuer wrote: > >> I would like that, along with the ability to bundle patterns with classes. >> >> On Wed, Sep 8, 2021, 1:13 PM Keith wrote: >> >>> Is there currently a way to 'bundle' a pattern with a type alias? And if >>> not, could that capability be added to the PatternSynonyms GHC extension? >>> (Is this the right place to ask, or should I be asking a GHC list?) >>> >>> --Keith >>> Sent from my phone with K-9 Mail. >>> ___ >>> 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. >> >> ___ >> 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. > > ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
Re: [Haskell-cafe] Bundle patterns with type aliases
These are great ideas! Could you please create a ghc tracker ticket with a tiny examples or two? There may be specific technical reasons we might not be able to do so for type synonyms in ghc, but I don’t see any obvious barriers in the case of David’s excellent idea, I’ve def seen lots of great code out there where you’d really want either associated pattern synonyms or to bundle pattern synonyms with the exported public interface for a type class. I’m sure there’s some devil in the details but these sound lovely. Step -1 is making up 1-2 toy examples and explaining what and why you want it on a ghc ticket! On Wed, Sep 8, 2021 at 1:25 PM David Feuer wrote: > I would like that, along with the ability to bundle patterns with classes. > > On Wed, Sep 8, 2021, 1:13 PM Keith wrote: > >> Is there currently a way to 'bundle' a pattern with a type alias? And if >> not, could that capability be added to the PatternSynonyms GHC extension? >> (Is this the right place to ask, or should I be asking a GHC list?) >> >> --Keith >> Sent from my phone with K-9 Mail. >> ___ >> 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. > > ___ > 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. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
