Toplevel - load cmo from given location

Toplevel - load cmo from given location

[Dawid Toton]

I've noticed stange behaviour:

The following works OK (using #directory directive):

#!/usr/bin/ocamlrun ocaml
#directory "/home/dt2/Calc1/CalcEngine/src/_build/extlib/"
#load "enum.cmo"
open Enum

But this version not (using the full path directly):

#!/usr/bin/ocamlrun ocaml
#load "/home/dt2/Calc1/CalcEngine/src/_build/extlib/enum.cmo"
open Enum

The problem is that it gives "Unbound module Enum" while no error about 
loading the cmo&cmi is shown.
So:
* if it finds correctly the enum.cmi: why "open Enum" doesn't work?
* if the cmi is not found, why I see no message like "*Cannot find file 
*/home/dt2/Calc1/CalcEngine/src/_build/extlib/enum.cmi*" - as chapter 
9.4 of docs suggests? Does the toplevel check for the cmi in the same 
location as cmo? *
(I tested this with the cmi file existing there as built by ocamlbuild)

Dawid

Re: [Caml-list] Toplevel - load cmo from given location

[Christophe TROESTLER]

On Fri, 09 Jan 2009 14:06:25 +0000, Dawid Toton wrote:
> 
> I've noticed stange behaviour:
> 
> The following works OK (using #directory directive):
> 
> #!/usr/bin/ocamlrun ocaml
> #directory "/home/dt2/Calc1/CalcEngine/src/_build/extlib/"
> #load "enum.cmo"
> open Enum
> 
> But this version not (using the full path directly):
> 
> #!/usr/bin/ocamlrun ocaml
> #load "/home/dt2/Calc1/CalcEngine/src/_build/extlib/enum.cmo"
> open Enum
> 
> The problem is that it gives "Unbound module Enum" while no error about loading the cmo&cmi is shown.

The #directory instruction is needed to find the .cmi.

My 0.02€,
ChriS

Re: [Caml-list] Toplevel - load cmo from given location

[Dawid Toton]

>> The problem is that it gives "Unbound module Enum" while no error about loading the cmo&cmi is shown.
> 
> The #directory instruction is needed to find the .cmi.

I see, so there are 2 problems:
* why the failure to load cmi is silent in this case?
* why the toplevel fails to check for cmi where the cmo is located? This 
looks as incorrect behaviour (the reference manual doesn't mention any 
exceptional rules for the #load directive).

Dawid

Re: [Caml-list] Toplevel - load cmo from given location

[Richard Jones]

On Fri, Jan 09, 2009 at 03:08:18PM +0000, Dawid Toton wrote:
> 
> >>The problem is that it gives "Unbound module Enum" while no error about 
> >>loading the cmo&cmi is shown.
> >
> >The #directory instruction is needed to find the .cmi.
> 
> I see, so there are 2 problems:
> * why the failure to load cmi is silent in this case?
> * why the toplevel fails to check for cmi where the cmo is located? This 
> looks as incorrect behaviour (the reference manual doesn't mention any 
> exceptional rules for the #load directive).

As you say this is kind of a bug.  You cannot solve it by assuming
some sort of one-to-one relationship between .cmi files and .cmo files
though.  You can have .cmi without .cmo, or .cmo without .cmi, or lots
of .cmi and a .cma, and probably other combinations.

Couple of practical points though: (1) Use ocamlfind in the toplevel
to solve all these problems:

  # #use "topfind";;
  - : unit = ()
  Findlib has been successfully loaded. Additional directives:
    #require "package";;      to load a package
    #list;;                   to list the available packages
    #camlp4o;;                to load camlp4 (standard syntax)
    #camlp4r;;                to load camlp4 (revised syntax)
    #predicates "p,q,...";;   to set these predicates
    Topfind.reset();;         to force that packages will be reloaded
    #thread;;                 to enable threads
  
  - : unit = ()
  # #require "netstring";;
  /usr/lib64/ocaml/pcre: added to search path
  /usr/lib64/ocaml/pcre/pcre.cma: loaded
  /usr/lib64/ocaml/unix.cma: loaded
  /usr/lib64/ocaml/netsys: added to search path
  /usr/lib64/ocaml/netsys/netsys.cma: loaded
  /usr/lib64/ocaml/netstring: added to search path
  /usr/lib64/ocaml/netstring/netstring.cma: loaded
  /usr/lib64/ocaml/netstring/netstring_top.cmo: loaded
  /usr/lib64/ocaml/netstring/netaccel.cma: loaded
  /usr/lib64/ocaml/netstring/netaccel_link.cmo: loaded

(2) Bugs should go in the bug tracker here:
http://caml.inria.fr/mantis/

Rich.

-- 
Richard Jones
Red Hat

Re: Toplevel - load cmo from given location

[Zheng Li]

Hi,

On 1/9/2009 3:06 PM, Dawid Toton wrote:
> But this version not (using the full path directly):
>
> #!/usr/bin/ocamlrun ocaml
> #load "/home/dt2/Calc1/CalcEngine/src/_build/extlib/enum.cmo"
> open Enum
>
> The problem is that it gives "Unbound module Enum" while no error about
> loading the cmo&cmi is shown.

It's because the toplevel doesn't have the "/home/dt2/..." in its paths, 
so it doesn't know where the enum.cmi is.

> So:
> * if it finds correctly the enum.cmi: why "open Enum" doesn't work?

No, it doesn't find the enum.cmi

> * if the cmi is not found, why I see no message like "*Cannot find file
> */home/dt2/Calc1/CalcEngine/src/_build/extlib/enum.cmi*" - as chapter

The enum.cmi was there, it was because the toplevel didn't know about 
this path. So it had the same effect as accessing a non-existed module 
or a module existed but not in the known paths (e.g. open NoSuchModule).

> 9.4 of docs suggests? Does the toplevel check for the cmi in the same
> location as cmo? *

No. Basically, cmi and cmo are two different things. You using one 
doesn't mean you'll use the other.

Using the "directory" directive or launching toplevel with "-I" 
parameters can add extra paths to toplevel (for accessing both cmi and cmo).

HTH.
--
Zheng