Was kompiliert Delphi 10.3.3 da???

[Uwe Raabe]

Zitat von Fritzew:

Delphi-Quellcode:

with fb := CalculateFooBar do begin
  writeLn(fb);
end;

// fb is not available here anymore.

Wozu dann überhaupt das with , wenn man doch wieder die Variable fb benutzen muss?

In Delphi würde man das in etwa so schreiben:

Delphi-Quellcode:

  begin
    var fb := CalculateFooBar;
    Writeln(fb);
  end;
  // fb is not available here anymore.

[Fritzew]

Zitat von Uwe Raabe:

Wozu dann überhaupt das with , wenn man doch wieder die Variable fb benutzen muss?

Im Prinzip hast Du recht.... Das geht aber noch weiter:

Zitat:

When the expression for the with statement is a Record or other value type, the new variable acts as an alias to toe original record, and any changes done on the identifier will directly affect the original record.

By contrast, assigning the record to a new local var declaration would create a copy opf the record on the stack:

Delphi-Quellcode:

var x: Person;
x.Name := "Peter";

with y := x do  
  y.Name := "Paul";
  
// x.Name is now Paul

Compared to:

Delphi-Quellcode:

var y := x;
y.Name := "Paul";

// x.Name is unchanged, as y is a separate copy