On Thu, 15 Nov 2007, Fernando Alegre wrote:

>
> The main problem I have with abstract types is that they are heavyweight
> since they need to be defined inside modules. In that particular, the
> proposed private types are also heavyweight.

I don't see modules as being that heavyweight.  Absent functors, they're 
just namespaces.  And Ocaml's cross-module inlining eliminates even most 
of that overhead- identity conversions are generally inlined and become 
no-ops.  Even with functors, the overhead is small, approximately that of 
calling a virtual function in C++ or Java.

Just my $0.02.

Brian