Re: [Caml-list] Calling the toplevel from the toplevel

[rixed@happyleptic.org]

> Actually you can, you just have to make sure that .cmi files are
> available in the search paths of the toplevel when you run your
> application.

Yes, it works now. AFAICT the cmi have always been available,
but anyway...

> > - I cannot let the user uses the toplevel directives "use" and "load"
> >   because both writes into stdout whatever the formatter passed to
> >   Toploop.execute_phrase (for "use" this is easily solvable by shadowing
> >   the toplevel implementation by another one that call Toploop.use_file
> >   with my own formatter, but for "load" I would have to copy a lot of
> >   code from topdirs.ml
> 
> Why not use Topdirs.dir_load with a custom formatter ?

Because I had not noticed that these functions were available.
This is handy. So I end up with something similar to you, except
I don't shadow that much directives (only those I know and use
regularly, and I'm not very experienced with the toplevel to say
the least).

> If you are interested, i started some time ago an emacs-like editor
> which can run in both curses and gtk mode and which integrates a
> toplevel.

Haha!, this is the very same reason why I was asking these questions.
Except that my project is just a small pet project consisting only
of less than 1k LOC, and I hope it will stay that way. I'm just used
to mix C and scheme to use the scheme repl to manipulate the running
C app and wanted to know how easy/hard it would be to have the same
"hackability" with Ocaml.

> I add to face the same problems. I solved them by using
> Toploop.execute_phrase directly and redefining all directives.

I've seen. We use very similar approach.
The funny thing is that when I started I was convinced that it was
not possible to call the Toploop evaluator from within itself, and
tried many other solutions, until I noticed that topfind.ml actually
does this to enrich the toplevel directives.

> Also another problem i had is that Toploop.execute_phrase does not
> prints errors on the given formatter but raises an exception instead,
> and the printer used in Toploop.loop (Errors.report_error) is in the
> module Errors for which the cmi is not available.

I give the exception to Toploop.print_exception_outcome :

        let top_eval cmd =
            let cmd = Rope.to_string cmd in
            Log.p "Executing '%s'" cmd ;
            try
                let l = Lexing.from_string cmd in
                let ph = !Toploop.parse_toplevel_phrase l in
                Toploop.execute_phrase true self#formatter ph
            with exn ->
                Toploop.print_exception_outcome self#formatter exn ;
                false in

but the exceptions are only pretty printed to a depth of 1, further
values being replaced by "_", so it's far from perfect.

> I used a hack which
> consists on parsing the output of Toploop.use_silently (file
> peps_top.ml, function eval_command).

Ooooh, I see! I'd never come up with this idea.

BTW, do you have any future plan for peps?