undefined symbol `caml_tuplify2' in dynamic rocaml extension

undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Jos Backus]

Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be accessed
from a dynamic Ruby extension (using Callback.register). Everything works,
except when I try to access the Ocaml type from Ruby the following Ruby
LoadError is emitted:

    undefined symbol: caml_tuplify2

So my question is: what do I need to do in order to satisfy this symbol? It
doesn't appear in any library. ocaml version is 3.09.2.

Thanks,
-- 
Jos Backus
jos at catnook.com

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Julien Moutinho]

On Tue, Jul 31, 2007 at 09:01:02PM -0700, Jos Backus wrote:
> Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be accessed
> from a dynamic Ruby extension (using Callback.register). Everything works,
> except when I try to access the Ocaml type from Ruby the following Ruby
> LoadError is emitted:
> 
>     undefined symbol: caml_tuplify2
> 
> So my question is: what do I need to do in order to satisfy this symbol? It
> doesn't appear in any library. ocaml version is 3.09.2.

AFAICS, when needed, caml_tuplifyN end up within the /tmp/camlstartup*.s file
mechanically generated at link time.
You can keep this file with -dstartup.

Unfortunately, due to its quasi-random name,
it is not easy to retrieve it mechanically.

Personally I have patched ocamlopt in order to have a -startup option
keeping camlstartup_<name_of_the_output>.o in the current directory.

Anyway, maybe there is a better way for your own concern.
Have a glance at -output-obj perhaps.

HTH.

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Mauricio Fernandez]

On Tue, Jul 31, 2007 at 09:01:02PM -0700, Jos Backus wrote:
> Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be accessed
> from a dynamic Ruby extension (using Callback.register). Everything works,
> except when I try to access the Ocaml type from Ruby the following Ruby
> LoadError is emitted:
> 
>     undefined symbol: caml_tuplify2
> 
> So my question is: what do I need to do in order to satisfy this symbol? It
> doesn't appear in any library. ocaml version is 3.09.2.

Do the examples included in rocaml work for you? In particular "oo", where an
abstract type is used from Ruby, and "simple", which passes tuples to a
function returning a tuple.  If you could pinpoint the conversion that's
triggering the problem (and it's indeed a problem caused by a Ruby <-> OCaml
conversion) we'd be one step away from fixing it.  Have you tried to
disassemble the extension and see where caml_tuplify2 is being called?

-- 
Mauricio Fernandez  -   http://eigenclass.org

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Mauricio Fernandez]

On Wed, Aug 01, 2007 at 09:44:22AM +0200, Julien Moutinho wrote:
> On Tue, Jul 31, 2007 at 09:01:02PM -0700, Jos Backus wrote:
> > Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be accessed
> > from a dynamic Ruby extension (using Callback.register). Everything works,
> > except when I try to access the Ocaml type from Ruby the following Ruby
> > LoadError is emitted:
> > 
> >     undefined symbol: caml_tuplify2
> > 
> > So my question is: what do I need to do in order to satisfy this symbol? It
> > doesn't appear in any library. ocaml version is 3.09.2.
> 
> AFAICS, when needed, caml_tuplifyN end up within the /tmp/camlstartup*.s file
> mechanically generated at link time.
> You can keep this file with -dstartup.
> 
> Unfortunately, due to its quasi-random name,
> it is not easy to retrieve it mechanically.
> 
> Personally I have patched ocamlopt in order to have a -startup option
> keeping camlstartup_<name_of_the_output>.o in the current directory.
> 
> Anyway, maybe there is a better way for your own concern.
> Have a glance at -output-obj perhaps.

rocaml already uses -output-obj; these are the steps it follows when building an
extension:

gcc -I. -Ipath/to/lib/ruby/1.8/i686-linux -I.  -fPIC -g -O2  -c oo_rocaml_wrapper.c
ocamlopt.opt -c   oo.ml
ocamlopt.opt -c   rubyOCamlUtil.ml
ocamlopt.opt  -output-obj -o oo_rocaml_runtime.o nums.cmxa oo.cmx \ 
              rubyOCamlUtil.cmx oo.o rubyOCamlUtil.o 
gcc -shared  -L'path/to/usr/lib' -Wl,-R'path/to/usr/lib' -o oo.so \
  oo_rocaml_wrapper.o oo_rocaml_runtime.o /usr/lib/ocaml/3.09.2/libasmrun.a \
  /usr/lib/ocaml/3.09.2/libunix.a /usr/lib/ocaml/3.09.2/libnums.a \
  -ldl -lcrypt -lm   -lc

oo_rocaml_wrapper.c and rubyOCamlUtil.ml are generated by rocaml, the actual
OCaml code is in oo.ml.

Under which circumstances would something like the above oo.so not be
self-contained as far as the OCaml code is concerned?

PS: I realize that the above only works as is on x86, Linux + Windows (maybe
elsewhere), but will fail on x86_64, whose linker cannot handle non-PIC code.
This is described in http://caml.inria.fr/mantis/view.php?id=3924
I believed it was fixed in 3.10 since the changelog indicates:
  - Intel/AMD 64 bits: generate position-independent code by default.
but I've had no success with 3.10 and -fPIC (I have to try again though, I
just realized that this could refer only to (2) in the bug report).

-- 
Mauricio Fernandez  -   http://eigenclass.org

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Gordon Henriksen]

On Aug 1, 2007, at 03:44, Julien Moutinho wrote:
> On Tue, Jul 31, 2007 at 09:01:02PM -0700, Jos Backus wrote:
>
>> Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be  
>> accessed from a dynamic Ruby extension (using Callback.register).  
>> Everything works, except when I try to access the Ocaml type from  
>> Ruby the following Ruby LoadError is emitted:
>>
>>     undefined symbol: caml_tuplify2
>>
>> So my question is: what do I need to do in order to satisfy this  
>> symbol? It doesn't appear in any library. ocaml version is 3.09.2.
>
> AFAICS, when needed, caml_tuplifyN end up within the /tmp/ 
> camlstartup*.s file mechanically generated at link time. You can  
> keep this file with -dstartup.
>
> Unfortunately, due to its quasi-random name, it is not easy to  
> retrieve it mechanically.
>
> Personally I have patched ocamlopt in order to have a -startup  
> option keeping camlstartup_<name_of_the_output>.o in the current  
> directory.
>
> Anyway, maybe there is a better way for your own concern. Have a  
> glance at -output-obj perhaps.
>
> HTH.

I wonder if there's a reason ocamlopt doesn't simply emit these glue  
functions alongside their uses as linkonce symbols. This is the same  
technique that a C++ compiler uses for template instantiations to  
avoid problems of this nature.

— Gordon

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Jos Backus]

On Wed, Aug 01, 2007 at 11:16:47AM +0200, Mauricio Fernandez wrote:
> On Tue, Jul 31, 2007 at 09:01:02PM -0700, Jos Backus wrote:
> > Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be accessed
> > from a dynamic Ruby extension (using Callback.register). Everything works,
> > except when I try to access the Ocaml type from Ruby the following Ruby
> > LoadError is emitted:
> > 
> >     undefined symbol: caml_tuplify2
> > 
> > So my question is: what do I need to do in order to satisfy this symbol? It
> > doesn't appear in any library. ocaml version is 3.09.2.
> 
> Do the examples included in rocaml work for you? In particular "oo", where an
> abstract type is used from Ruby, and "simple", which passes tuples to a
> function returning a tuple.

Yes; all the examples work fine.

The case that is failing is where I try to call functions in a .a created with
ocamlopt (it's an internal library written in Ocaml). I had to modify the
Makefile to add the .a to LOCAL_LIBS and surround it with -Wl,--whole-archive
.a -Wl,--no-whole-archive.  Without this option the resulting .so built by
rocaml would not have the Ruby-visible symbols (`KPP.make' in this case) and
the extension would fail with caml_named_value() returning NULL because the
named value would not be present.

> If you could pinpoint the conversion that's triggering the problem (and it's
> indeed a problem caused by a Ruby <-> OCaml conversion) we'd be one step
> away from fixing it.  Have you tried to disassemble the extension and see
> where caml_tuplify2 is being called?

I'll have a look. I do see references to caml_tuplify2 in other .a's as well.

Thanks for rocaml!

-- 
Jos Backus
jos at catnook.com

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Jos Backus]

On Wed, Aug 01, 2007 at 09:17:02AM -0700, Jos Backus wrote:
> On Wed, Aug 01, 2007 at 11:16:47AM +0200, Mauricio Fernandez wrote:
[snip]
> > If you could pinpoint the conversion that's triggering the problem (and it's
> > indeed a problem caused by a Ruby <-> OCaml conversion) we'd be one step
> > away from fixing it.  Have you tried to disassemble the extension and see
> > where caml_tuplify2 is being called?
> 
> I'll have a look. I do see references to caml_tuplify2 in other .a's as well.

It turns out my extension doesn't call it but one of the required libraries
does.

Here's what I am doing:

Exerpt from extconf.rb:

    # extension name, XXX in   require 'XXX'
    EXT_NAME = "kpp"

    Interface.generate("kpp") do
      def_class("KPP") do |c|
	t = c.abstract_type
	fun "make", STRING => t
	method "eval", [t, STRING] => LIST(STRING)
      end
    end

$ ruby extconf.rb
$ make
[lots of errors because of unfound header files]
$ vi Makefile
[Add `-I/usr/lib/ocaml' to INCFLAGS]
$ make
kpp_rocaml_wrapper.c:39: error: missing terminating " character
$ vi kpp_rocaml_wrapper.c
[Change line 39:

static VALUE String_list_caml_to_ruby(value v);"

to

static VALUE String_list_caml_to_ruby(value v);
]
$ make
gcc -I. -I/usr/lib/ruby/1.8/i386-linux -I/usr/lib/ruby/1.8/i386-linux -I. -I/usr/lib/ocaml  -fPIC -O2 -g -pipe -m32 -march=i386 -mtune=pentium4 -Wall  -fPIC  -c kpp_rocaml_wrapper.c
kpp_rocaml_wrapper.c: In function `string_ruby_to_caml_safe':
kpp_rocaml_wrapper.c:133: warning: implicit declaration of function `caml_alloc_string'
kpp_rocaml_wrapper.c: At top level:
kpp_rocaml_wrapper.c:45: warning: 'do_raise_exception' defined but not used
kpp_rocaml_wrapper.c:59: warning: 'do_raise_exception_tag' defined but not used
ocamlopt.opt -c   rubyOCamlUtil.ml
ocamlopt.opt  -output-obj -o kpp_rocaml_runtime.o nums.cmxa rubyOCamlUtil.cmx rubyOCamlUtil.o 
gcc -shared  -L"/usr/lib" -o kpp.so kpp_rocaml_wrapper.o kpp_rocaml_runtime.o /usr/lib/ocaml/libasmrun.a /usr/lib/ocaml/libunix.a /usr/lib/ocaml/libnums.a -lruby  -lpthread -ldl -lcrypt -lm   -lc
$ cat test_kpp.rb 
require 'kpp'

kpp = KPP.make ""
p kpp.eval("")
$ ruby test_kpp.rb 
test_kpp.rb:3:in `make': Couldn't find OCaml value 'KPP.make'. (StandardError)
        from test_kpp.rb:3
$ vi Makefile
[Add `-Wl,--whole-archive ../kpp/kpp.a -Wl,--no-whole-archive' to LOCAL_LIBS]
$ make clean all
$ ruby test_kpp.rb
./kpp.so: ./kpp.so: undefined symbol: camlStr__parse_368 - ./kpp.so (LoadError)
        from test_kpp.rb:1
$ vi Makefile
[Add `/usr/lib/ocaml/str.a' to LOCAL_LIBS]
$ make clean all
$ ruby test_kpp.rb
./kpp.so: ./kpp.so: undefined symbol: camlCamlinternalOO__create_object_opt_357 - ./kpp.so (LoadError)
        from test_kpp.rb:1
$ vi Makefile
[Add `/usr/lib/ocaml/stdlib.a' to LOCAL_LIBS]
$ make clean all
$ ruby test_kpp.rb
./kpp.so: ./kpp.so: undefined symbol: caml_hash_univ_param - ./kpp.so (LoadError)
        from test_kpp.rb:1
$ vi Makefile
[Add `/usr/lib/ocaml/libasmrun.a' (again) to LOCAL_LIBS]
$ make clean all
$ ruby test_kpp.rb
./kpp.so: ./kpp.so: undefined symbol: caml_tuplify2 - ./kpp.so (LoadError)
        from test_kpp.rb:1
$ 

At this point, LOCAL_LIBS looks like this:

LOCAL_LIBS = kpp_rocaml_runtime.o /usr/lib/ocaml/libasmrun.a \
    /usr/lib/ocaml/libunix.a /usr/lib/ocaml/libnums.a -Wl,--whole-archive \
    ../kpp/kpp.a -Wl,--no-whole-archive /usr/lib/ocaml/str.a \
    /usr/lib/ocaml/stdlib.a /usr/lib/ocaml/libasmrun.a
 
This is where I'm stuck.

-- 
Jos Backus
jos at catnook.com

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension (UPDATE)

[Jos Backus]

On Wed, Aug 01, 2007 at 10:59:07AM -0700, Jos Backus wrote:
> On Wed, Aug 01, 2007 at 09:17:02AM -0700, Jos Backus wrote:
> > On Wed, Aug 01, 2007 at 11:16:47AM +0200, Mauricio Fernandez wrote:
> [snip]
> > > If you could pinpoint the conversion that's triggering the problem (and it's
> > > indeed a problem caused by a Ruby <-> OCaml conversion) we'd be one step
> > > away from fixing it.  Have you tried to disassemble the extension and see
> > > where caml_tuplify2 is being called?
> > 
> > I'll have a look. I do see references to caml_tuplify2 in other .a's as well.
> 
> It turns out my extension doesn't call it but one of the required libraries
> does.
> 
> Here's what I am doing:
[snip]

Some good news. We got this to work by creating a kpp.ml file (containing the
Callback.register calls) in the extension directory, and adding some values to
CAML_LIBS, CAML_OBJS and CAML_INCLUDES. Yay!

It looks like we are really close. The next (final?) issue is that we have a
function with signature

    val eval : kpp -> string -> value list -> value list

where

    type value =
	| Vstr of string
	| Vtup of value list

which we want to export to Ruby. We tried:

    Interface.generate(EXT_NAME) do
      value = sym_variant("value") do |t|
	non_constant :Vstr, STRING
	non_constant :Vtup, LIST(t)
      end

      def_class("KPP") do |c|
	t = c.abstract_type
	fun "make", STRING => t
	method "eval", [t, STRING, value] => LIST(STRING)
      end
    end

but it doesn't work (it segfaults inside the extension).

How does one represent `value' on the Ruby side?

Btw, besides having to remove the stray `"' we also found that we had to patch
the kpp_rocaml_wrapper.c to make it compile, basically doing a `%s/t_value
/t_value_/g' in this case.

Hope this feedback is useful. Thanks!

-- 
Jos Backus
jos at catnook.com

rocaml bug + fix

[Jos Backus]

On Wed, Aug 01, 2007 at 10:59:07AM -0700, Jos Backus wrote:
[snip]
> $ make
> kpp_rocaml_wrapper.c:39: error: missing terminating " character
> $ vi kpp_rocaml_wrapper.c
> [Change line 39:
> 
> static VALUE String_list_caml_to_ruby(value v);"
> 
> to
> 
> static VALUE String_list_caml_to_ruby(value v);
> ]

--- rocaml.rb.orig      2007-08-01 19:30:01.000000000 -0400
+++ rocaml.rb   2007-08-01 19:30:33.000000000 -0400
@@ -512,7 +512,7 @@
 
     def caml_to_ruby_prototype
       <<-EOF
-static VALUE #{@typename}_list_caml_to_ruby(value v);"
+static VALUE #{@typename}_list_caml_to_ruby(value v);
 
       EOF
     end

-- 
Jos Backus
jos at catnook.com

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension (UPDATE)

[Mauricio Fernandez]

On Wed, Aug 01, 2007 at 04:24:05PM -0700, Jos Backus wrote:
> On Wed, Aug 01, 2007 at 10:59:07AM -0700, Jos Backus wrote:
> > On Wed, Aug 01, 2007 at 09:17:02AM -0700, Jos Backus wrote:
> > > On Wed, Aug 01, 2007 at 11:16:47AM +0200, Mauricio Fernandez wrote:
> > [snip]
> > > > If you could pinpoint the conversion that's triggering the problem (and it's
> > > > indeed a problem caused by a Ruby <-> OCaml conversion) we'd be one step
> > > > away from fixing it.  Have you tried to disassemble the extension and see
> > > > where caml_tuplify2 is being called?
> > > 
> > > I'll have a look. I do see references to caml_tuplify2 in other .a's as well.
> > 
> > It turns out my extension doesn't call it but one of the required libraries
> > does.
> > 
> > Here's what I am doing:
> [snip]
> 
> Some good news. We got this to work by creating a kpp.ml file (containing the
> Callback.register calls) in the extension directory, and adding some values to
> CAML_LIBS, CAML_OBJS and CAML_INCLUDES. Yay!

Yes, I wrote a very long message telling you exactly this (that you needed to
use CAML_LIBS so that -output-obj could work correctly) late at night but
forgot to send it :)

> It looks like we are really close. The next (final?) issue is that we have a
> function with signature
> 
>     val eval : kpp -> string -> value list -> value list
> 
> where
> 
>     type value =
> 	| Vstr of string
> 	| Vtup of value list
> 
> which we want to export to Ruby. We tried:
> 
>     Interface.generate(EXT_NAME) do
>       value = sym_variant("value") do |t|
> 	non_constant :Vstr, STRING
> 	non_constant :Vtup, LIST(t)
>       end
[...]
> but it doesn't work (it segfaults inside the extension).
> 
> How does one represent `value' on the Ruby side?

I think you have to wrap the LIST(t) in a TUPLE():

  value = sym_variant("value") do |t|
   non_constant :Vstr, STRING
   non_constant :Vtup, TUPLE(LIST(t))
  end

I'll try to either auto-detect this or perform a compile-time check.

> Btw, besides having to remove the stray `"' we also found that we had to patch
> the kpp_rocaml_wrapper.c to make it compile, basically doing a `%s/t_value
> /t_value_/g' in this case.

Chris Waterson has kindly sent me a patch fixing the problems you saw; I've
just pushed it to the online repository, along with an example of the above
TUPLE(LIST(t)) in examples/variants.

I'll work on the INCFLAGS issue so there's no need to hand-edit the generated
Makefile/wrappers.

-- 
Mauricio Fernandez  -   http://eigenclass.org 

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension (UPDATE)

[Mauricio Fernandez]

On Thu, Aug 02, 2007 at 11:20:50AM +0200, Mauricio Fernandez wrote:
> > It looks like we are really close. The next (final?) issue is that we have a
> > function with signature
> > 
> >     val eval : kpp -> string -> value list -> value list
> > 
> > where
> > 
> >     type value =
> > 	| Vstr of string
> > 	| Vtup of value list
> > 
> > which we want to export to Ruby. We tried:
> > 
> >     Interface.generate(EXT_NAME) do
> >       value = sym_variant("value") do |t|
> > 	non_constant :Vstr, STRING
> > 	non_constant :Vtup, LIST(t)
> >       end
> [...]
> > but it doesn't work (it segfaults inside the extension).
> > 
> > How does one represent `value' on the Ruby side?
> 
> I think you have to wrap the LIST(t) in a TUPLE():
> 
>   value = sym_variant("value") do |t|
>    non_constant :Vstr, STRING
>    non_constant :Vtup, TUPLE(LIST(t))
>   end
> 
> I'll try to either auto-detect this or perform a compile-time check.

Ignore that; I forgot that rocaml already detects when such extra boxing is
needed and performs it automatically, so   non_constant :Vtup, LIST(foo)
should work already. It can't be due to the type being recursive either
because that works fine in the tree example. 

Just to make sure, are you calling  eval as in

  kpp.eval(str, [[[ :Vtup, [ [[:Vstr, "foo"]] ] ]]])
                
The outer pair of [ ] because it's a block, the next one because it holds a
LIST, then the block represented as [symbol, value] where value is a block
holding a list of [symbol, value] blocks.

If you've got the wrong number of [ ], maybe the generated extension isn't
detecting it, and hence the crash.
		       
Yes, it's hard to get the above right, so I'll see if something can be done
from Ruby to make it easier.

-- 
Mauricio Fernandez  -   http://eigenclass.org

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension (UPDATE)

[Jos Backus]

On Thu, Aug 02, 2007 at 11:58:57AM +0200, Mauricio Fernandez wrote:
> On Thu, Aug 02, 2007 at 11:20:50AM +0200, Mauricio Fernandez wrote:
> > > It looks like we are really close. The next (final?) issue is that we have a
> > > function with signature
> > > 
> > >     val eval : kpp -> string -> value list -> value list
> > > 
> > > where
> > > 
> > >     type value =
> > > 	| Vstr of string
> > > 	| Vtup of value list
> > > 
> > > which we want to export to Ruby. We tried:
> > > 
> > >     Interface.generate(EXT_NAME) do
> > >       value = sym_variant("value") do |t|
> > > 	non_constant :Vstr, STRING
> > > 	non_constant :Vtup, LIST(t)
> > >       end
> > [...]
> > > but it doesn't work (it segfaults inside the extension).
> > > 
> > > How does one represent `value' on the Ruby side?
> > 
> > I think you have to wrap the LIST(t) in a TUPLE():
> > 
> >   value = sym_variant("value") do |t|
> >    non_constant :Vstr, STRING
> >    non_constant :Vtup, TUPLE(LIST(t))
> >   end
> > 
> > I'll try to either auto-detect this or perform a compile-time check.
> 
> Ignore that; I forgot that rocaml already detects when such extra boxing is
> needed and performs it automatically, so   non_constant :Vtup, LIST(foo)
> should work already. It can't be due to the type being recursive either
> because that works fine in the tree example. 
 
Thanks. We ended up doing

    Interface.generate(EXT_NAME) do
      kpp_value_t = sym_variant("kpp_value_t") do |t|
	non_constant :Vstr, STRING
	non_constant :Vtup, LIST(t)
      end

      def_class("KPP") do |c|
	t = c.abstract_type
	ctxt = LIST(kpp_value_t)
	fun "make", STRING => t
	method "eval", [t, STRING, ctxt] => ctxt
	...
      end
    end

so we can say

    kpp.eval("", [[:Vstr, "woot!"]])

> Just to make sure, are you calling  eval as in
> 
>   kpp.eval(str, [[[ :Vtup, [ [[:Vstr, "foo"]] ] ]]])
>                 
> The outer pair of [ ] because it's a block, the next one because it holds a
> LIST, then the block represented as [symbol, value] where value is a block
> holding a list of [symbol, value] blocks.
> 
> If you've got the wrong number of [ ], maybe the generated extension isn't
> detecting it, and hence the crash.
> 		       
> Yes, it's hard to get the above right, so I'll see if something can be done
> from Ruby to make it easier.

That would be nice. Thanks for the explanation Mauricio.

And thanks to everybody responding on this thread - it looks like we are all
set now.

-- 
Jos Backus
jos at catnook.com

Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension (UPDATE)

[Jos Backus]

On Thu, Aug 02, 2007 at 11:20:50AM +0200, Mauricio Fernandez wrote:
> On Wed, Aug 01, 2007 at 04:24:05PM -0700, Jos Backus wrote:
> > On Wed, Aug 01, 2007 at 10:59:07AM -0700, Jos Backus wrote:
[snip]
> > Some good news. We got this to work by creating a kpp.ml file (containing the
> > Callback.register calls) in the extension directory, and adding some values to
> > CAML_LIBS, CAML_OBJS and CAML_INCLUDES. Yay!
> 
> Yes, I wrote a very long message telling you exactly this (that you needed to
> use CAML_LIBS so that -output-obj could work correctly) late at night but
> forgot to send it :)

Heh. All's well that ends well.

> > Btw, besides having to remove the stray `"' we also found that we had to patch
> > the kpp_rocaml_wrapper.c to make it compile, basically doing a `%s/t_value
> > /t_value_/g' in this case.
> 
> Chris Waterson has kindly sent me a patch fixing the problems you saw; I've
> just pushed it to the online repository, along with an example of the above
> TUPLE(LIST(t)) in examples/variants.

Yeah, I dragged Chris into working on this yesterday (thanks Chris!) and he
beat me to the patch :)
 
> I'll work on the INCFLAGS issue so there's no need to hand-edit the
> generated Makefile/wrappers.

That would be nice. While you're at it, can you add LOCAL_LIBS, too? Those
were the only variables we needed to change in the Makefile.

> -- Mauricio Fernandez  -   http://eigenclass.org 

Thanks again Mauricio.

-- 
Jos Backus
jos at catnook.com