Records in Haskell
anthony_clayden at clear.net.nz
Thu Mar 1 21:52:29 CET 2012
Ian Lynagh <igloo <at> earth.li> writes:
> On Thu, Mar 01, 2012 at 07:58:42AM +0000, AntC wrote:
> > SORF's whadyoumaycalls are at the Kind level. (I'm not opposed to them
> > they're new-fangled, I'm opposed because I can't control the namespace.)
> I haven't followed everything, so please forgive me if this is a stupid
> question, but if you implement this variant of SORF:
> then do you get the behaviour of SORF when using field names starting
> with a lower-case letter, and DORF when they start with an upper-case
And you get "In my opinion, this is ugly, since the selector can be either a
type name or a label and the semantics are nonsame. Rather, we need scoped
So if we open the gate for "ugly", do we also open it for "hacks" and
Then we also have a solution for updating higher-ranked typed fields.
I guess this is all for decision by the implementors.
If we need to go into scoped instances, I'd be really scared -- that seems
like a huge, far-reaching change, with all sorts of opportunity for mysterious
compile fails and inexplicable behaviour-changing from imports.
I have some creative ideas for introducing overlapping instances; shall I run
them up the flagpole as well?
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