Hello,

Vladimir Ulchenko wrote:

> > that was a joke. I have written numerous macros which would easily
> > resist being ported to Delphi, but I don't really use them in
> > production code :)
> 
> why not? I do it all the time

the small ones are all right, but I was rather thinking of a little
framework which I built upon macros and templates and which basically
emulated Delphi's "safecall" convention (i.e. COM exception
firewalling) in C++.

> I wonder whether is is possible to implement something similar in
> newer delphi versions in order to avoid aforementioned ubiquitous
> nested try/finally boredom?

With Delphi's generics it's possible to build some kind of equivalent
for std::auto_ptr<>. However generics differ from templates in that
they're strictly typed at declaration time. I assume your
MakeBeginEndUpdate() is a function template that generates calls to
obj->BeginUpdate() and obj->EndUpdate() regardless of what type obj has
(some kind of static duck typing). You can't do that with generics;
you'd have to write specific scopeguards for TListBox, TTreeView etc.


My generic scope guard, however, is easily portable using anonymous
methods:


// -----
uses
  SysUtils;


type
  TScopeGuard = record
  private
    FExitProc: TProc;
  public
    constructor Create (InitProc, ExitProc: TProc);
  end;


constructor TScopeGuard.Create (InitProc, ExitProc: TProc);
begin
  InitProc;
  FExitProc := ExitProc; // note: assign AFTER calling InitProc!
end;


....
procedure TForm1.Button1Click (Sender: TObject);
var
  LVSG: TScopeGuard;
begin
  LVSG.Create (procedure begin ListView1.BeginUpdate end,
    procedure begin ListView1.EndUpdate end);
  ...
end;
// -----


-- 
Moritz


"Hey, it compiles! Ship it!"