On 05.07.2019 14:58, Martok wrote:
Am 05.07.2019 um 12:20 schrieb Ondrej Pokorny:
Anything that even looks like a subrange cannot be used for these interfaces.
You may use enumerations for these interfaces - you may just not fill
them directly but through an integer variable in between when reading
from outside.
Then you're not using them *in* the interface ;-)
For records you could use such a workaround:
program Project1;
{$mode objfpc}
{$modeswitch advancedrecords}
type
TMyEnum = (one, two, three);
TMyRecord = record
public
function IsValid: Boolean;
public
case Boolean of
False: ( // real values
Enum: TMyEnum;
);
True: ( // used for interface
EnumIntf: Integer;
{$IF SizeOf(Integer)<>SizeOf(TMyEnum)}
{$ERROR Size mismatch}
{$ENDIF}
);
end;
{ TMyRecord }
function TMyRecord.IsValid: Boolean;
begin
Result := EnumIntf is TMyEnum;
end;
var
R: TMyRecord;
begin
// fill R with data ...
Randomize;
FillChar(R, SizeOf(R), Random(High(Byte)));
// check validity
if R.IsValid then
Writeln('R is valid')
else
Writeln('R is not valid');
Writeln(R.EnumIntf);
ReadLn;
end.
Best
Ondrej
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