Re: [Caml-list] A question about custom toplevels

["Nicolás Ojeda Bär" <nicolas.ojeda.bar@lexifi.com>]

Dear Jocely,

I do not think this is currently possible.

When you enter a phrase into the toplevel (custom or otherwise), it is
compiled much the same way as if it had been written in a file and
passed to ocamlc.
To do so the compiler needs access to the signature information stored
in the .cmi files of all referenced modules. This is completely
independent of whether the code of those modules is linked into the
toplevel or loaded separately which is what ocamlmktop is about.

Note that it works the same way even for modules of the stdlib. The
reason "it just works" in that case is because a flag "-I <stdlibdir>"
is added implicitly. But if you pass the -nostdlib flag to the
toplevel, this implicit flag is not added, and the toplevel will not
be able to find the .cmi files of the stdlib in much the same way in
cannot find foo.cmi.

Best wishes,
Nicolás

On Thu, Mar 8, 2018 at 9:19 AM, Jocelyn Sérot
<Jocelyn.Serot@univ-bpclermont.fr> wrote:
> Hello,
>
> I recently stumbled on a problem and am wondering whether it comes from a
> misunderstanding or a bad usage.
>
> When a custom toplevel is built using the [ocamlmktop] program, it seems
> that the modules which are « included » must be present in the path when the
> so-built toplevel is executed afterwards.
>
> For example, suppose that directory « bar » contains  a file foo.ml, with,
> let say the definition « let v=100 ».
> Then, making
>
> ocamlfind ocamlc -c -o foo.cmo foo.ml
> ocamlfind ocamlc -a -o foo.cma foo.cmo
> ocamlfind ocamlmktop -o foo.top foo.cma
>
> creates foo.top, which, when executed, behaves has expected.
>
> $ ./foo.top
>         OCaml version 4.06.0
>
> # Foo.v;;
> - : int = 100
>
> But, when trying to execute foo.top from another directory, for ex from
> ../bar, i get the following error :
>
> $ ./bar/foo.top
>         OCaml version 4.06.0
>
> # Foo.v;;
> Error: Unbound module Foo
>
> The error disappears if i add option « -I ./bar » when lauching foo.top (or,
> equivently execute the directive « #directory ./bar »).
>
> Is there a way to build a « self-contained » custom toplevel which could be
> executed without any explicit reference to the modules it included at
> creation ?
>
> Jocelyn
>
> ps : i tried the -custom option but, not surprisingly, it does not solve the
> pb since it only refers to external C code.