[Haskell] RE: Extensible records: Static duck typing

[Barney Hilken]

> What about just implementing the cheapest solution that still gets  
> us most
> of the way?

> (3) If it is as cheap (to implement) as advertised then there is no  
> great
> risk involved. If it turns out the missing features are a great
> show-stopper for some people (which I don't believe) then let them  
> present
> their case afterwards, with good examples at hand. We can still  
> decide to
> aim for a higher goal in the long term.

> If in doubt, chose the solution that is easier to implement.

Since this paper, there have been several proposals which can be 90%  
implemented as libraries, using either functional dependencies or  
associated types. These all have much more expressive type systems  
than the SPJ paper, yet need very little compiler support. The  
question is, which one (if any) should get this small but necessary  
support?

Barney.