Proposal: Derive Lift for all data types in the template-haskell library
eir at cis.upenn.edu
Wed Sep 23 00:59:07 UTC 2015
+1 from me. Now that it's so easy, I think Lift should be instanced for all concrete types exported from the boot libraries. Do make sure to communicate with the authors of th-lift and th-orphans at some point, though.
On Sep 22, 2015, at 10:12 AM, Ryan Scott <ryan.gl.scott at gmail.com> wrote:
> The DeriveLift extension has landed in GHC HEAD, so now it's become apparent that the bikeshed needs a new coat of paint. The only Lift instances at the moment are base types , but with DeriveLift, it would be possible to implement Lift for many for data types with ease.
> I'll make (what I hope is) an uncontroversial first suggestion: we should derive Lift for every data type in the template-haskell library itself. These instances have proved to be useful for library authors who need to convert to and from the TH AST (th-desugar, for example, relies on this functionality via orphan instances ).
> Adding this would break some code out in the wild (the th-lift  and th-orphans  packages come to mind; there may be others), so I'll request feedback before marching forth with this proposal.
> Ryan S.
>  http://hackage.haskell.org/package/template-haskell-22.214.171.124/docs/Language-Haskell-TH-Syntax.html#t:Lift
>  http://hackage.haskell.org/package/th-desugar-126.96.36.199/docs/src/Language-Haskell-TH-Desugar-Lift.html
>  http://hackage.haskell.org/package/th-lift
>  http://hackage.haskell.org/package/th-orphans
> Libraries mailing list
> Libraries at haskell.org
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