On Mon, Nov 07, 2011 at 08:31:04PM +0200, Wolfgang Jeltsch wrote:
The problem with this approach is that different labels do not have different representations at the value level. In my record system, I use label definitions like the following ones:
data MyName1 = MyName1
data MyName2 = MyName2
Instead of class Has (r :: *) (f :: String) (t :: *) where (as on the wiki), would it be possible to have something like class Has (r :: *) (ft :: *) (f :: ft) (t :: *) where (where ft stands for field type)? This could also solve the representation-hiding problem: foo.field would use the string "field" as the field name, as in the proposal on the wiki page. But foo.Field (capital first letter) would use the constructor Field that is in scope. If you don't want to export the field getter then capitalise the first letter and don't export the constructor. Thanks Ian