Re: [Caml-list] A shallow option type

2012-05-05 Thread Andreas Rossberg
On May 5, 2012, at 15.33 h, Goswin von Brederlow wrote: What I want is a type 'a shallow = NULL | 'a (constraint 'a != 'b shallow) This is a form of negation, which cannot be expressed in conventional type systems. Just consider what it should mean in the presence of type abstraction:

Re: [Caml-list] Proposal for extensible open datatypes

2012-01-06 Thread Andreas Rossberg
On Jan 6, 2012, at 07.26 h, Andrej Bauer wrote: I would be interested to hear what propeties of Ocaml you had to give up to get this interesting extension working? For example, what happens with checking for exhaustivness of match? Caml performs various optimizations in pattern matching, why are

Re: [Caml-list] Ocaml and the Fragile Base Class Problem

2011-08-28 Thread Andreas Rossberg
On Aug 28, 2011, at 12.11 h, Gerd Stolpmann wrote: Am Sonntag, den 28.08.2011, 11:31 +0200 schrieb Andreas Rossberg: On Aug 28, 2011, at 01.08 h, Gerd Stolpmann wrote: Let me point out one final thing. Information hiding is simply not a core concept of OO - which is in the first place

Re: [Caml-list] First-class module and higher-order types

2011-08-20 Thread Andreas Rossberg
On Aug 20, 2011, at 05.26 h, Jacques Garrigue wrote: On 2011/08/20, at 0:38, Arnaud Spiwack wrote: • On the theoretical side, how hard is it to design a variant of Hindley-Milner's typing algorithm with type-family quantification? (I understand that Ocaml's typing machinery is pretty hard