[OCaml] Add a callback example

It is based on the the Python and Go examples.

Examples/ocaml/callback/Makefile

@@ -0,0 +1,31 @@
+TOP          = ../..
+SWIGEXE      = $(TOP)/../swig
+SWIG_LIB_DIR = $(TOP)/../$(TOP_BUILDDIR_TO_TOP_SRCDIR)Lib
+SWIGOPT      =
+SRCS         = example.c
+TARGET       = example
+INTERFACE    = example.i
+PROGFILE     = runme.ml
+OBJS         = example.o
+
+check: build
+	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' TARGET='$(TARGET)' ocaml_run
+
+build: static
+
+static:
+	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' SRCS='$(SRCS)' \
+	SWIG_LIB_DIR='$(SWIG_LIB_DIR)' SWIGEXE='$(SWIGEXE)' \
+	SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' \
+	PROGFILE='$(PROGFILE)' OBJS='$(OBJS)' \
+	ocaml_static_cpp
+
+static_top:
+	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' SRCS='$(SRCS)' \
+	SWIG_LIB_DIR='$(SWIG_LIB_DIR)' SWIGEXE='$(SWIGEXE)' \
+	SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' \
+	PROGFILE='$(PROGFILE)' OBJS='$(OBJS)' \
+	ocaml_static_cpp_toplevel
+
+clean:
+	$(MAKE) -f $(TOP)/Makefile SRCDIR='$(SRCDIR)' TARGET='$(TARGET)' ocaml_clean

Examples/ocaml/callback/example.c

@@ -0,0 +1,3 @@
+/* File : example.c */
+
+#include "example.h"

Examples/ocaml/callback/example.h

@@ -0,0 +1,20 @@
+/* File : example.h */
+
+#include <iostream>
+
+class Callback {
+public:
+	virtual ~Callback() { std::cout << "Callback::~Callback()" << std::endl; }
+	virtual void run() { std::cout << "Callback::run()" << std::endl; }
+};
+
+
+class Caller {
+	Callback *_callback;
+public:
+	Caller(): _callback(0) {}
+	~Caller() { delCallback(); }
+	void delCallback() { delete _callback; _callback = 0; }
+	void setCallback(Callback *cb) { delCallback(); _callback = cb; }
+	void call() { if (_callback) _callback->run(); }
+};

Examples/ocaml/callback/example.i

@@ -0,0 +1,10 @@
+/* File : example.i */
+%module(directors="1") example
+%{
+#include "example.h"
+%}
+
+%feature("director") Callback;
+
+%include "example.h"
+

Examples/ocaml/callback/runme.ml

@@ -0,0 +1,30 @@
+(* file: runme.ml
+
+This file illustrates cross-language polymorphism using directors. *)
+
+open Swig
+open Example
+
+let new_OCamlCallback ob meth args =
+  match meth with
+    | "run" -> print_endline "OCamlCallback.run()"; C_void
+    | _ -> (invoke ob) meth args
+
+let caller = new_Caller '()
+
+let _ = print_endline "Adding and calling a normal C++ callback"
+let _ = print_endline "----------------------------------------"
+
+let callback = new_Callback '()
+let _ = caller -> "setCallback" (callback)
+let _ = caller -> "call" ()
+let _ = caller -> "delCallback" (0)
+
+let _ = print_endline "\nAdding and calling an OCaml callback"
+let _ = print_endline "------------------------------------"
+
+let callback = new_derived_object new_Callback (new_OCamlCallback) '()
+let _  = caller -> "setCallback" (callback)
+let _  = caller -> "call" ()
+let _  = caller -> "delCallback" (0)
+let _  = print_endline "\nOCaml exit"

Examples/ocaml/check.list

@@ -1,5 +1,6 @@
 # see top-level Makefile.in
 argout_ref
+callback
 class
 contract
 scoped_enum

Examples/ocaml/stl/example.i

@@ -7,6 +7,4 @@
 #define ENABLE_STRING_VECTOR
 %include stl.i
 
-%feature("director");
-
 %include example.h