Hi Bob,

I have been teaching OCaml for a while, and like you I found error
messages to be a major issue. This motivated my recent work on
improving type error messages for OCaml.

My patch is ready for action.

opam switch 4.03.0+pr102
ocamlc -new-type-errors -strict-sequence test.ml

For more information: http://arthur.chargueraud.org/teach/ocaml/

If you have a chance to try it on beginners, please share your feedback!

Best,
Arthur Charguéraud

PS: I know of on-going efforts to try and improve parsing errors too
---it be great to have those fixed too.

PPS: although my patch is usable, I have planned to fix a few things.
- Have a two-column display for type errors on applications,
    with expected types and provided types.
- Remove bracket delimiters around types and use newlines instead.
- Have "-new-type-errors" imply "-strict-sequence",
- Document the fact it does not support GADTs, and does not
   typecheck with "-principal", in particular code that uses overloading
   of record fields.
- Isolate the code associated with "-new-type-errors" so that the patch
   may have a chance of being considered for integration in OCaml.

Greetings. Bob Muller here, in the CS dept. at Boston College. I've set out to develop an intro CS course in ML that I hope will be well-suited for similar universities in the US. My original plan was to teach the course in SML but after talking with a few people at neighboring schools, I switched to OCaml. I am now in the final weeks of the first run of the course. I plan to document my experience more fully at some point but I wanted to touch base with the OCaml community because I'm teaching the course again in the spring and I am leaning toward switching to F#. While OCaml has in many respects been great and it's easy to see that my students find the OCaml style of coding very compelling, there are significant problems. Of course, OCaml wasn't designed for teaching but I'm hoping that someone on this list might be able to advise me about solutions to some of these that I just don't know about. 1. Error messages: It's difficult to give good type errors for ML but I was hoping that the state-of-the-art of type error reporting had improved. When my students receive a type error, they are utterly mystified, 2. GUIs: several of my problem sets work with simple graphics (e.g., rendering tessellations) or animations (e.g., a maze walk or a simplified form of tetris, or the game "Flow"). We have been hobbling along with the Graphics and Labltk modules for this but it has been more pain than my students ought to know. We also have some problem sets that work with audio so I would like support for that. Any thoughts, ideas and/or leads on either of these would be much appreciated. I already plan to look at js_of_ocaml more closely. Thank you, Bob Muller -- Caml-list mailing list. Subscription management and archives: https://sympa.inria.fr/sympa/arc/caml-list Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs