Re: Pointer to method C++ style

2009-07-23 Thread BLS 

Sergey Gromov wrote:

Use case: I'm writing an ActiveX plug-in for a dynamic language.  The



class Component : IUnknown


WOW!

But shouldn't you use

class Component : IDispatch
{
  HRESULT QueryInterface( REFIID riid, LPVOID * ppvObj) {};
  ULONG   AddRef() {};
  ULONG   Release(){};

  // plus IDispatch methods
  // GetTypeInfoCount, GetTypeInfo, GetIDsOfNames, Invoke.
  // to support late binding ?
}

instead ?

Beside, John C. (Juno library) is a specialist (guru) regarding this 
topic. maybe he is willing to help.


However, I am _very_ interested in having/seeing the source of a very 
basic ActiveX control. Any chance that you share the core implementation 
with us ?

björn

Re: Pointer to method C++ style

2009-07-23 Thread Sergey Gromov 
Thu, 23 Jul 2009 12:37:42 +0200, BLS wrote:

Sergey Gromov wrote:
 Use case: I'm writing an ActiveX plug-in for a dynamic language.  The

 However, I am _very_ interested in having/seeing the source of a very 
 basic ActiveX control. Any chance that you share the core implementation 
 with us ?

Sorry, I'm not a guru at all, so ActiveX was a misnomer.  What I'm
writing is a simple in-process server DLL which implements a couple of
interfaces.

Re: Pointer to method C++ style

2009-07-23 Thread Sergey Gromov 
Thu, 23 Jul 2009 04:11:14 + (UTC), BCS wrote:

 Hello Sergey,
 
 Is there a way to declare and statically initialize some sort of
 pointer to method, and later call it for an actual object instance?
 
 
 dosn't work but might point you in the right direction:
 
 template Pn2Fn(R, char[] method)
 {
  ReturnTypeOf!(mixin(R. ~ method)) Pn2Fn(R r, ArgsOf!(mixin(R. ~ 
 method)) args)
  {
   return mixin(r.~method~(args););
  }
 
 }

Thanks for the advice.  The following code actually works:

import std.stdio;

struct Handler(T)
{
  string name;
  void function(T instance) handler;
}

class A
{
  void method1() { writefln(method1); }
  void method2() { writefln(method2); }

  void call(int i)
  {
LOOKUP_TABLE[i].handler(this);
  }

private:

  static Handler!(A)[] LOOKUP_TABLE =
  [
{ method1, callMethod!(method1) },
{ method2, callMethod!(method2) }
  ];

  static void callMethod(string name)(A instance)
  {
mixin(instance. ~ name ~ (););
  }
}

void main()
{
  A a = new A;
  a.call(0);
  a.call(1);
}

Re: Pointer to method C++ style

2009-07-23 Thread Steven Schveighoffer 
On Wed, 22 Jul 2009 23:47:30 -0400, Sergey Gromov snake.sc...@gmail.com  
wrote:



Is there a way to declare and statically initialize some sort of pointer
to method, and later call it for an actual object instance?


I don't know why the non constant expression error happens, but  
constructing a delegate from function pointers is pretty simple:


import tango.io.Stdout;

struct Method
{
char[] name;
void function() method;
}

class Component
{
void method1() {Stdout(method1).newline;}
void method2() {Stdout(method2).newline;}


// this works, but not sure why I couldn't initialize via a simple  
array assign...

static Method[] LOOKUP_TABLE;
static this()
{
LOOKUP_TABLE = new Method[2];
LOOKUP_TABLE[0] = Method(method1, Component.method1);
LOOKUP_TABLE[1] = Method(method2, Component.method2);
}

void call(int i)
{
// construct a delegate to call
void delegate() dg;
dg.ptr = cast(void*)this;
dg.funcptr = LOOKUP_TABLE[i].method;
// call the delegate
dg();
}
}

void main()
{
Component a = new Component;
a.call(0);
a.call(1);
}

---
outputs:

method1
method2

-Steve

Re: Pointer to method C++ style

2009-07-23 Thread BLS 

Sergey Gromov wrote:

Thu, 23 Jul 2009 12:37:42 +0200, BLS wrote:




Sorry, I'm not a guru at all, so ActiveX was a misnomer.  What I'm
writing is a simple in-process server DLL which implements a couple of
interfaces.


Oh, that's sad. :(

well, especially in this case I would suggest to have a look on this page :
http://www.dsource.org/projects/juno/wiki/ComProgramming

--- I think John's juno.com.server module contains almost everything you 
need.


good luck

Re: Pointer to method C++ style

2009-07-23 Thread Sergey Gromov 
Thu, 23 Jul 2009 19:07:43 +0200, BLS wrote:

 Sergey Gromov wrote:
 Sorry, I'm not a guru at all, so ActiveX was a misnomer.  What I'm
 writing is a simple in-process server DLL which implements a couple of
 interfaces.
 
 Oh, that's sad. :(
 
 well, especially in this case I would suggest to have a look on this page :
 http://www.dsource.org/projects/juno/wiki/ComProgramming

Thanks, I'll look into it when I have time.

Re: Pointer to method C++ style

2009-07-23 Thread Sergey Gromov 
Thu, 23 Jul 2009 11:54:40 -0400, Steven Schveighoffer wrote:

 On Wed, 22 Jul 2009 23:47:30 -0400, Sergey Gromov snake.sc...@gmail.com  
 wrote:
 
 Is there a way to declare and statically initialize some sort of pointer
 to method, and later call it for an actual object instance?
 
 I don't know why the non constant expression error happens, but  
 constructing a delegate from function pointers is pretty simple:

It's my understanding that you cannot construct a delegate from a
function pointer because they use different calling conventions.  Though
you show here that it *is* possible to construct a delegate from another
delegate you dissected earlier.

  LOOKUP_TABLE[0] = Method(method1, Component.method1);
  LOOKUP_TABLE[1] = Method(method2, Component.method2);

These two lines are weird.  ``pragma(msg)`` shows that type of
``method1`` is ``void function()`` while it must be ``void delegate()``
for a non-static member because of difference in calling convention.
Actually I think that taking an address of a non-static member in a
static context must be a compile time error.