+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.
Richard
On Sep 22, 2015, at 10:12 AM, Ryan Scott
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 [1], 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 [2]).
Adding this would break some code out in the wild (the th-lift [3] and th-orphans [4] packages come to mind; there may be others), so I'll request feedback before marching forth with this proposal.
Ryan S.
----- [1] http://hackage.haskell.org/package/template-haskell-2.10.0.0/docs/Language-H... [2] http://hackage.haskell.org/package/th-desugar-1.5.4.1/docs/src/Language-Hask... [3] http://hackage.haskell.org/package/th-lift [4] http://hackage.haskell.org/package/th-orphans _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries