> 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/Plan (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
