Thema: Delphi into Record?

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himitsu

Registriert seit: 11. Okt 2003
Ort: Elbflorenz
44.071 Beiträge
 
Delphi 12 Athens
 
#13

AW: into Record?

  Alt 28. Aug 2022, 23:54
Ohhhh, die neuen Custom Managed Records verhalten sich übrigens ganz anders.
Sie werden "sofort" freigegeben, wenn sie nicht mehr benötigt werden ... nicht erst zum Ende des aktuellen Scopes.


Delphi-Quellcode:
type
  TTest = record
    Name: string;
    constructor Create(S: string);
    class operator Implicit(S: string): TTest;
    class operator Initialize(out Dest: TTest);
    class operator Finalize(var Dest: TTest);
    class operator Assign(var Dest: TTest; const [ref] Src: TTest);
  end;

constructor TTest.Create(S: string);
begin
  Name := S;
  ShowMessage('Create ' + Name);
end;

class operator TTest.Implicit(S: string): TTest;
begin
  Result.Name := S;
  ShowMessage('Impicit ' + Result.Name);
end;

class operator TTest.Finalize(var Dest: TTest);
begin
  ShowMessage('Final ' + Dest.Name);
  Dest.Name := '';
end;

class operator TTest.Initialize(out Dest: TTest);
begin
  Dest.Name := 'Init';
  ShowMessage('Init');
end;

class operator TTest.Assign(var Dest: TTest; const [Ref] Src: TTest);
begin
  if Dest.Name = 'Initthen
    ShowMessage('Assign ' + Src.Name)
  else
    ShowMessage('Assign ' + Src.Name + '>' + Dest.Name);
  Dest.Name := Src.Name;
end;

procedure TForm11.FormCreate(Sender: TObject);
var
  Var1a, Var1, Var2a, Var2, Var3a, Var3, Var4a, Var4: TTest;
begin // Init Var1a..Var4
  Var1a := 'Var1a'; // Init/Implicit (Temp)Var1a / Assign Var1a / Final (Temp)Var1a
  Var1 := TTest.Create('Var1'); // Init/Create (New)Var1 / Assign Var1 / Final (New)Var1
  var Inline1 := TTest.Create('Inline1'); // Init/Create Inline1
  TTest.Create('Temp1'); // Init/Create/Final Temp1
  Beep;
  if Tag = 0 then
    Var2a := 'Var2a'; // Init/Implicit (Temp)Var2a / Assign Var2a / Final (Temp)Var2a
  if Tag = 0 then
    Var2 := TTest.Create('Var2'); // Init/Create (New)Var2 / Assign Var2 / Final (New)Var2
  if Tag = 0 then
    var Inline2 := TTest.Create('Inline2'); // Init/Create/Final Inline2
  if Tag = 0 then
    TTest.Create('Temp2'); // Init/Create/Final Temp2
  Beep;
  if Tag = 0 then begin
    Var3a := 'Var3a'; // Init/Implicit (Temp)Var3a / Assign Var3a / Final (Temp)Var3a
    Var3 := TTest.Create('Var3'); // Init/Create (New)Var3 / Assign Var3 / Final (New)Var3
    var Inline3 := TTest.Create('Inline3'); // Init/Create Inline3
    TTest.Create('Temp3'); // Init/Create/Final Temp3
  end; // ###NOT FInal Temp3 / Final Inline3
  Beep;
  if Tag = 0 then begin
    Var4a := 'Var4a'; // Init/Implicit (Temp)Var4a / Assign Var4a / Final (Temp)Var4a
    Var4 := TTest.Create('Var4'); // Init/Create (New)Var4 / Assign Var4 / Final (New)Var4
    var Inline4 := TTest.Create('Inline4'); // Init/Create Inline4
    TTest.Create('Temp4'); // Init/Create/Final Temp4
    Beep;
    begin
      TTest.Create('Temp6'); // Init/Create/Final Temp6
      Beep;
      TTest.Create('Temp7'); // Init/Create/Final Temp7
      Beep;
    end; // ###NOT Final Temp7/Temp6
    Beep;
    begin
      var Temp8 := TTest.Create('Temp8'); // Init/Create Temp8
      Beep;
      Temp8 := TTest.Create('Temp9'); // Init/Create (New)Temp9 / Assign Temp9>Temp8 / Final (New)Temp9
      Beep;
    end; // NOT Final (Temp8)Temp9
    Beep;
    ShowMessage('Show'); // Show
    Beep;
  end; // ###NOT Final Temp4 / Final Inline4
  Beep;
end; // ###NOT Final Temp1 / Final Inline1/Var4..Var1a
Neuste Erkenntnis:
Seit Pos einen dritten Parameter hat,
wird PoSex im Delphi viel seltener praktiziert.
  Mit Zitat antworten Zitat