simple example of using ocamlbuild with C

simple example of using ocamlbuild with C

[Ashish Agarwal]

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Please can someone explain in simple terms how to build C code with
ocamlbuild. The example at the wiki has more going on than I can understand.
Here's a simple test program:

---- avg.c ---
#include <stdio.h>
#include <stdlib.h>
#include <caml/mlvalues.h>
#include <caml/memory.h>

double avg(double *v, int N) {
  int i;
  double sum = 0.0;

  for (i = 0; i < N; ++i) {
    sum += v[i];
  }

  double ans = sum/N;
  return ans;
}

value avg_c(value v) {
  CAMLparam1(v);
  double ans = avg((double *) v, Wosize_val(v)/Double_wosize);
  CAMLreturn(caml_copy_double(ans));
}

--- math.mli ---
val avg : float array -> float

--- math.ml ---
external avg : float array -> float = "avg_c"

--- run.ml ---
print_float (Math.avg [|1.0; 1.5|]);;
print_newline()


Command line instructions for producing byte and native code are as follows.
I would like to please know how to get ocamlbuild to do this.

Byte code:
% cc -c -I /usr/local/lib/ocaml/ avg.c
% ocamlc -c math.mli
% ocamlc -c math.ml
% ocamlc -custom -o run.byte avg.o math.cmo run.ml
% run.byte
1.25

Native code:
% cc -c -I /usr/local/lib/ocaml/ avg.c
% ocamlopt -c math.mli
% ocamlopt -c math.ml
% ocamlopt -o run.native avg.o math.cmx run.ml
% run.native
1.25

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Re: [Caml-list] simple example of using ocamlbuild with C

[Matthieu Dubuget]

---- myocamlbuild.ml ------

open Ocamlopen Ocamlbuild_plugin
open Command
;;
dispatch begin function
 | After_rules ->
     flag ["link"; "ocaml"; "byte"] (A"-custom");
     dep  ["link"; "ocaml"; "use_my_math"] ["avg.o"];
 | _ -> ()
end

---- _tags ----- (do not forget the endline before end of file)
<run.{native,byte}>: use_my_math

++++++++++++++++

Works for me.

Salutations

P.S.

 I had to modify the beginning of

---- avg.c ---
#include <stdio.h >
#include <stdlib.h>
#include <caml/mlvalues.h>
#include <caml/memory.h>

into

---- avg.c ---
#include <caml/mlvalues.h>
#include <caml/memory.h>
#include <caml/alloc.h>

Type checking question

[Axel Poigné]

Hello

why does this work


#class xxx (x:int) =

object(self)

     val mutable _x = x
     method get = _x

end;;
               class xxx : int -> object val mutable _x : int method  
get : int end

#class yyy (x:int) =

object(self)
     inherit xxx x

     method set y = _x <- y

end;;

               class yyy :
   int ->
   object val mutable _x : int method get : int method set : int ->  
unit end

#class zzz (x:xxx) =

object(self)

     method get = x#get

end;;

             class zzz : xxx -> object method get : int endlet yy =  
new yyy 8;;

#let zz = new zzz((yy:yyy):>xxx);;

val zz : zzz = <obj>

#zz#get;;
- : int = 8

I would expect  that yy is of not  type yyy = int -> ...

Axel

Re: [Caml-list] Type checking question

[Jacques GARRIGUE]

From: Axel Poigné <axel.poigne@iais.fraunhofer.de>

> why does this work
[...]
> #class yyy (x:int) =
> object(self)
>      inherit xxx x
>      method set y = _x <- y
> end;;
> class yyy : int ->
>    object val mutable _x : int method get : int method set : int -> unit end
> #let yy = new yyy 8;;
> val yy : yyy
> 
> I would expect  that yy is of not  type yyy = int -> ...

The confusion is due to the fact a class definition actually defines 4 things:
* the class itself, whose type is displayed
* a class type with same name, which is the displayed type _without_ the
  parameters (here, without int ->)
* an object type with same name, which is constructed from the public
  methods of the class type
* an extensible object type #yyy, which is unifiable with any subclass of
  yyy.

The yyy in "new yyy" is the class, but the one in "val yy : yyy" is
the object type.

Jacques Garrigue

Re: [Caml-list] Type checking question

[Axel Poigné]

Hello Jacques

many thanks for the clarification. The example is an abstraction of a  
bigger piece of software with some unexpected behaviour (actually  
defining the ttk widget in terms of classes and building new composite  
widgets ).

Your answer proves that this is not due to the afore-mentioned problems.

Axel

Re: [Caml-list] simple example of using ocamlbuild with C

[Ashish Agarwal]

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Thanks!


On Jan 10, 2008 3:05 AM, Matthieu Dubuget <matthieu.dubuget@gmail.com>
wrote:
> ---- myocamlbuild.ml ------
>
> open Ocamlopen Ocamlbuild_plugin
> open Command
> ;;
> dispatch begin function
> | After_rules ->
> flag ["link"; "ocaml"; "byte"] (A"-custom");
> dep ["link"; "ocaml"; "use_my_math"] ["avg.o"];
> | _ -> ()
> end
>
> ---- _tags ----- (do not forget the endline before end of file)
> <run.{native,byte}>: use_my_math
>
> ++++++++++++++++
>
> Works for me.
>
> Salutations
>
> P.S.
>
> I had to modify the beginning of
>
>
> ---- avg.c ---
> #include <stdio.h >
> #include <stdlib.h>
> #include <caml/mlvalues.h>
> #include <caml/memory.h>
>
> into
>
> ---- avg.c ---
>
> #include <caml/mlvalues.h>
> #include <caml/memory.h>
> #include <caml/alloc.h>
>

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