[fpc-devel] [] property overloads

[Ben Grasset]

On Tue, Jul 9, 2019 at 3:17 PM Ryan Joseph <genericptr at gmail.com> wrote:

> Please post an example of the var/out bug if you don’t mind. Just to be
> sure.
>

I don't know if it necessarily *is* a bug.

It would definitely be if it worked with literals as input, which is the
impression I had based on what someone reported previously for some reason,
but again, after testing it myself that is not the case.

program Example;

{$mode ObjFPC}
{$modeswitch AdvancedRecords}

type
  TRecord = record
  private
    function GetBoolOut(out Index: PtrUInt): Boolean;
    function GetBoolVar(var Index: PtrUInt): Boolean;
  public
    property OutBools[out Index: PtrUInt]: Boolean read GetBoolOut;
    property VarBools[var Index: PtrUInt]: Boolean read GetBoolVar;
  end;

  function TRecord.GetBoolOut(out Index: PtrUInt): Boolean;
  begin
    Result := Index > 5000;
  end;

  function TRecord.GetBoolVar(var Index: PtrUInt): Boolean;
  begin
    Result := Index > 5000;
  end;

var
  R: TRecord;
  I: PtrUInt = 5000;

begin
  // Error: Variable identifier expected
  WriteLn(R.OutBools[5001]);
  // Error: Variable identifier expected
  WriteLn(R.VarBools[5001]);
  // Works fine
  WriteLn(R.OutBools[I]);
  // Works fine
  WriteLn(R.VarBools[I]);
end.

So the behavior as far as making sense based on the definition of "out" and
"var" is correct. The only thing that's really "strange" to me is the fact
that getters are completely unrestricted in that regard, while setters
explicitly need {$VARPROPSETTER ON}.
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