Yes, that _is_ obvious but then puts the burden on the programmer to define the getters. It also misses the setters issue entirely. Each field can definitely be made into a class and records can be composed dynamically, HList-style. I think HList is _the_ facility for doing this. How do you create a "record" that has a field dictionary for updates and retrievals and stores the order of the fields for serialization? I think HList does provide for the order of records since it keeps them in a list of sorts. Can serialization of these HList-style records serialization be efficient in this case? Would updating fields be efficient? I tried composing my records using HList and that made GHC run out of memory and bomb out. Simon Peyton-Jones fixed the problem promptly but since I was not familiar with the profiler at the time I never got to measuring the pickling efficiency. I figured if it's that tough on the compiler then maybe I should pick an easier path. Thanks, Joel On Jan 4, 2006, at 8:41 AM, Ketil Malde wrote:
Isn't the obvious solution to declare a class here? I.e.
class HasProfits h where profits :: h -> Word64
data Pot = Pot { pProfits :: !Word64, pAmounts = ![Word64] }
instance HasProfits Pot where profits = pProfits