lambda functions with classic 32 bit Borland compiler ?

[MJS@mjs.us]

Sample anonymous function usage with C++ classic compiler without lambda functions:


//---------------------------------------------------------------------------
From 'How to Handle Delphi Anonymous Methods in C++' RAD Studio help.
This needs to be included once so the function pointers can be wrapped.
//---------------------------------------------------------------------------
enum _DummyType{};
template <typename INTF, // Interface with Invoke
          typename F,    // Functor type
          typename R,    // Return type
          typename P1 = _DummyType,  // Param #1
          typename P2 = _DummyType,  // Param #2
          typename P3 = _DummyType,  // Param #3
          typename P4 = _DummyType,  // Param #4
          typename P5 = _DummyType>  // Param #5
class TMethodRef : public TCppInterfacedObject<INTF>
{
private:
  F callback;
public:
  TMethodRef(F _callback) : callback(_callback) {}
  INTFOBJECT_IMPL_IUNKNOWN(TInterfacedObject);
  R __fastcall Invoke(P1 p1) {
    return callback(p1);
  }
  R __fastcall Invoke(P1 p1, P2 p2) {
    return callback(p1, p2);
  }
  R __fastcall Invoke(P1 p1, P2 p2, P3 p3) {
    return callback(p1, p2, p3);
  }
  R __fastcall Invoke(P1 p1, P2 p2, P3 p3, P4 p4) {
    return callback(p1, p2, p3, p4);
  }
  R __fastcall Invoke(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5) {
    return callback(p1, p2, p3, p4, p5);
  }
};


//Sample TSessionProc callback
//---------------------------------------------------------------------------
void LookUpProc(System::TObject* obj)
{
  TIWApplication *ASession =  (TIWApplication *)obj;
  UserSession()->tmpStr = ASession->IP+","+ASession->LastAccess.FormatString("yyyy-mm-dd hh:nns");
}


// Sample callback usage
//---------------------------------------------------------------------------
void __fastcall TMJForm::btnRefreshAsyncClick(TObject *Sender, TStringList *EventParams)
{
  auto_ptr<TStringList> sl(new TStringList), sl2(new TStringList);
  
  gSessions->GetList(sl.get());
  for(int i=0;i<sl->Count;i++) {
    gSessions->LookUp(sl->Strings[i],new TMethodRef<Iwlfsessionlist::TSessionProc,void (*)(System::TObject*),void,System::TObject* >(LookUpProc));
    sl2->DelimitedText = UserSession()->tmpStr;
    ...
  }
}