Strong Typing, Dynamic Languages, What to do?

[Shriram Krishnamurthi <sk@cs.brown.edu>]

I think for a large % of programming tasks, the ML family is just
about the sweet spot.  It breaks down in two places.

One is language design: as someone pointed out, not having any type
system means, in effect, that you have all type systems: there's
nothing to get in the way of your coding experiment.  But very few
people need that power (contrary to the claims made on c.l.s).

A bigger problem is handling some kinds of growth and extensibility,
for which subtyping seems to be essential (though Greg Cooper at Brown
is trying to convince me otherwise, and not failing so far).  Merging
object polymorphism with parametric polymorphism, doing this in the
presence of type inference, and offering users principal types -- this
is a huge big open problem.

Shriram