Looping in Adam Gundry, who did the work! Simon
| -----Original Message----- | From: ghc-devs [mailto:[email protected]] On Behalf Of AntC | Sent: 15 October 2013 22:42 | To: [email protected] | Subject: Re: Status update on overloaded records work? | | > Johan Tibell <johan.tibell@...> writes: | > | > I'm curious about the current status of the overloaded records work. | | Hi Johan, I think Adam has documented as he's gone along: | http://ghc.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields/Pla | n | (And that points to implementation notes.) | | I'll leave Adam/Simon to comment more fully, but from my point of view | as | an observer with some 'skin in the game' ... | | > Is the design the same as when the project started? | | No: | - Higher-Ranked types can't be supported | -- and SPJ's initial proposal put a lot of weight on them. | There's an easy (IMO) work-round; | but it does compromise backward compatibility. | + Type changing update _is_ supported (with limits) | I think that was a justified trade-off for H-R types. | + Adam has been able to support Lenses. | | - (What I was hoping for but didn't get.) | No compiler flag to suppress creating selector functions. | This would have allowed records to be declared re-using the same | name; | but left it entirely to the developer as to how to access them. | (I was trying to promote the TH and/or Lenses cottage industries.) | | > Did we manage to keep the types simple? | | I guess simplicity is in the eye of the beholder ;-) | For 'gettable' fields, the sugar is as per SPJ's suggestion. | There isn't sugar for updating. | | The un-sugared types are pretty gnarly. | I suspect that'll mean obscure and confusing error messages. | | | AntC | | _______________________________________________ | ghc-devs mailing list | [email protected] | http://www.haskell.org/mailman/listinfo/ghc-devs _______________________________________________ ghc-devs mailing list [email protected] http://www.haskell.org/mailman/listinfo/ghc-devs
