I'm trying to use this feature, but I'm having some trouble: All of my records contain a parameterless `class function Create: TWhateverRecord; static;`.
Now, when I try to contain one within the other, I'm stumbling across this compiler error: Error: Overloaded identifier "CREATE" isn't a function I guess this is because both records now have a `Create` function with the same signature. But how can I resolve that conflict? And one more question: Does `Default(TComposedRecord)` correctly intialize the complete structure? Kind regards, Thomas ----- Original Message ----- From: Mattias Gaertner via fpc-pascal <[email protected]> To: [email protected] <[email protected]> Sent: Monday, October 19, 2026, 11:40:23 Subject: [fpc-pascal] Record Composition Hi all, Thanks to Frederic Kehrein FPC main now supports Record Composition: A record can now "contain" another record and have that record's members appear as its own. Firstly this allows easy and automated conversion of C code, which uses anonymous structs and unions introduced in C11, into Pascal and to use C libraries frictionless and transparently through the same types and interfaces. Secondly it allows for non trailing and multiple variant parts. And last but not least it can avoid {$IFDef} structures within the record definition allowing to reuse existing types. The feature is enabled with {$modeswitch RecordComposition} It is not part of any mode by default. Example: ------------------------ program demo; {$mode objfpc}{$H+} {$modeswitch advancedrecords} {$modeswitch recordcomposition} type TPoint = record X, Y: Integer; procedure Offset(dx, dy: Integer); end; TSize = record Width, Height: Integer; function Area: Integer; end; TRectangle = record contains TopLeft: TPoint; // named composition contains TSize; // unnamed composition function Right: Integer; end; procedure TPoint.Offset(dx, dy: Integer); begin Inc(X, dx); Inc(Y, dy); end; function TSize.Area: Integer; begin Result := Width * Height; end; function TRectangle.Right: Integer; begin Result := X + Width; // composed members, no qualifier needed end; var r: TRectangle; begin r.X := 10; // same as r.TopLeft.X r.Y := 20; r.Width := 300; r.Height := 200; r.Offset(5, 5); // calls TPoint.Offset with Self = r.TopLeft WriteLn(r.TopLeft.X, ' ', r.Right, ' ', r.Area); // 15 315 60000 end. ------------------------ See here for the more information: https://wiki.freepascal.org/FPC_New_Features_Trunk#Record_Composition Mattias _______________________________________________ fpc-pascal maillist - [email protected] https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal _______________________________________________ fpc-pascal maillist - [email protected] https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
