[Caml-list] [ANN] ocaml-lua v1.0: OCaml binding of Lua library

[Caml-list] [ANN] ocaml-lua v1.0: OCaml binding of Lua library

[Paolo Donadeo]

I'm happy to announce the first release of ocaml-lua, the OCaml
binding of the Lua library. With ocaml-lua you can embed a Lua
interpreter in an OCaml program in a few lines of code, and use Lua
for configuration or customization purposes.

Here are some references:

The homepage of the project is hosted on OCaml Forge:
http://ocaml-lua.forge.ocamlcore.org/
The complete library reference (ocamldoc generated) is here:
http://ocaml-lua.forge.ocamlcore.org/api-lua/
Source tarballs are on the download page on OCaml Forge:
http://forge.ocamlcore.org/frs/?group_id=167
The official GIT repository is here:
http://forge.ocamlcore.org/scm/browser.php?group_id=167
Bug reports and feature requests are on my page on GitHub:
https://github.com/pdonadeo/ocaml-lua/issues

I hope it could be useful.


-- 
Paolo

Re: [Caml-list] [ANN] ocaml-lua v1.0: OCaml binding of Lua library

[Florent Monnier]

Le samedi 01 septembre 2012 16:03:18, Paolo Donadeo a écrit :
> I'm happy to announce the first release of ocaml-lua, the OCaml
> binding of the Lua library. With ocaml-lua you can embed a Lua
> interpreter in an OCaml program in a few lines of code, and use Lua
> for configuration or customization purposes.
> 
> Here are some references:
> 
> The homepage of the project is hosted on OCaml Forge:
> http://ocaml-lua.forge.ocamlcore.org/
> The complete library reference (ocamldoc generated) is here:
> http://ocaml-lua.forge.ocamlcore.org/api-lua/
> Source tarballs are on the download page on OCaml Forge:
> http://forge.ocamlcore.org/frs/?group_id=167
> The official GIT repository is here:
> http://forge.ocamlcore.org/scm/browser.php?group_id=167
> Bug reports and feature requests are on my page on GitHub:
> https://github.com/pdonadeo/ocaml-lua/issues
> 
> I hope it could be useful.

It is useful at least for me ;)
Thanks a lot!

There is a problem with the returned status, and to make ocaml-lua able to be 
compiled with both Lua 5.1.X and 5.2.X,

in Lua 5.1.X there is:

/* thread status; 0 is OK */
#define LUA_YIELD       1
#define LUA_ERRRUN      2
#define LUA_ERRSYNTAX   3
#define LUA_ERRMEM      4
#define LUA_ERRERR      5


in Lua 5.2.X there is:

/* thread status */
#define LUA_OK          0
#define LUA_YIELD       1
#define LUA_ERRRUN      2
#define LUA_ERRSYNTAX   3
#define LUA_ERRMEM      4
#define LUA_ERRGCMM     5
#define LUA_ERRERR      6


and in ocaml-lua there is:

let thread_status_of_int = function
  | 0 -> LUA_OK
  | 1 -> LUA_YIELD
  | 2 -> LUA_ERRRUN
  | 3 -> LUA_ERRSYNTAX
  | 4 -> LUA_ERRMEM
  | 5 -> LUA_ERRERR
  | _ -> failwith "thread_status_of_int: unknown status value"


I asked to join the project but I didn't commit anything because I don't know 
how to fix this kind of translations.

I've found this kind of mismatch in other ocaml bindings when the real values 
are used instead of the symbolic names, but it seems that this kind of code is 
written for performance purpose.

In my own projects I always use a switch to convert from C to ocaml, and an 
array in the other direction, as in:
http://www.linux-nantes.org/%7Efmonnier/ocaml/ocaml-wrapping-c.php#ref_enums


So my question is, what is the better way to handle this kind of problems with 
this kind of translations ?


And even with the other method (switch/array), we can use the C preprocessor 
on the C side, and add a default at the end of the switch, but what is the 
recommended method for the OCaml side ? If there is an additional value for 
the enum, should we include it or not when compiled with the older version of 
the API ? (and raise an exception). Or generate different variants to reflect 
the API at compiled time ?


-- 
Best Regards
Florent

Re: [Caml-list] [ANN] ocaml-lua v1.0: OCaml binding of Lua library

[Francois Berenger]

On 09/04/2012 08:57 AM, Florent Monnier wrote:
> Le samedi 01 septembre 2012 16:03:18, Paolo Donadeo a écrit :
>> I'm happy to announce the first release of ocaml-lua, the OCaml
>> binding of the Lua library. With ocaml-lua you can embed a Lua
>> interpreter in an OCaml program in a few lines of code, and use Lua
>> for configuration or customization purposes.

Is there the same thing for Haskell?

Some OCaml binding to Haskell libraries or embedding an Haskell 
interpreter in OCaml programs? I'm just curious.

Thanks,
F.

Re: [Caml-list] [ANN] ocaml-lua v1.0: OCaml binding of Lua library

[Paolo Donadeo]

I don't know how to solve the problem of translating such things
automagically, and I suspect it's simply impossible.

Aside from this problem, ocaml-lua is a binding of Lua 5.1.x, and 5.2
is not (still) supported. It's not only a matter of some enums, the
language itself changed from 5.1 to 5.2:
http://www.lua.org/manual/5.2/manual.html#8

The work is not so lengthy, but it requires attention (I have to
carefully check the new behaviour wrt. the two garbage collectors) and
it's not on top on my todo list. Do you really need Lua 5.2? :-)

In any case, until ocaml-lua for Lua 5.2 is not out, I strongly
recommend you to link with Lua 5.1, which is present in Debian and
Ubuntu:
http://packages.ubuntu.com/precise/lua5.1
http://packages.debian.org/squeeze/lua5.1


-- 
Paolo