Seems like it's mixed up in some way with the FPC-style enumerator
operator, so the "class" version is recognized but not actually implemented
currently or something.
The normal way for classes/records/objects is to implement a GetEnumerator
function, anyways. Here's an expanded-on version of your example, using
your generic constants feature:
program Test;
{$mode ObjFPC}
{$PointerMath On}
{$modeswitch AdvancedRecords}
type
generic TConstArray<T; const N: PtrUInt> = array[0..N] of T;
generic TArrayEnumerator<T; const N: PtrUInt> = record
public type
PT = ^T;
public const
HIGH_INDEX = N;
private
CurrentIndex: PtrUInt;
DataPointer: PT;
public
function GetCurrent: T; inline;
class function Create(const A: PT): TArrayEnumerator; static; inline;
function MoveNext: Boolean; inline;
property Current: T read GetCurrent;
end;
generic TRec<T; const N: PtrUInt> = record
public type
TRecEnumerator = specialize TArrayEnumerator<T, N>;
private
FData: specialize TConstArray<T, N>;
public
class operator Initialize(var Rec: TRec);
function GetEnumerator: TRecEnumerator; inline;
end;
function TArrayEnumerator.GetCurrent: T;
begin
Result := DataPointer[CurrentIndex];
end;
class function TArrayEnumerator.Create(const A: PT): TArrayEnumerator;
begin
with Result do begin
DataPointer := A;
CurrentIndex := -1;
end;
end;
function TArrayEnumerator.MoveNext: Boolean;
begin
Inc(CurrentIndex);
Result := CurrentIndex <= HIGH_INDEX;
end;
class operator TRec.Initialize(var Rec: TRec);
var I: PtrUInt;
begin
for I := 0 to N do Rec.FData[I] := I;
end;
function TRec.GetEnumerator: TRecEnumerator;
begin
Result := TRecEnumerator.Create(@FData);
end;
var
Arr: specialize TRec<SizeInt, 5>;
Value: SizeInt;
begin
for Value in Arr do WriteLn(Value);
end.
On Tue, Apr 23, 2019 at 2:08 PM Ryan Joseph <r...@thealchemistguild.com>
wrote:
> Is "class operator enumerator” supposed to work or is this a bug that it
> compiles but doesn’t do anything? Seems like it should work.
>
> ===========================
>
> {$mode objfpc}
> {$modeswitch advancedrecords}
>
> program test;
>
> type
> TArrayEnumerator = class
> public type
> TArrayValue = integer;
> public
> function GetCurrent: TArrayValue;
> constructor Create(a: pointer);
> property Current: TArrayValue read GetCurrent;
> function MoveNext: Boolean;
> end;
> TRec = record
> class operator enumerator(a: TRec): TArrayEnumerator;
> end;
>
> class operator TRec.Enumerator(a: TRec): TArrayEnumerator;
> begin
> result := TArrayEnumerator.Create(@a);
> end;
>
> function TArrayEnumerator.GetCurrent: TArrayValue;
> begin
> end;
>
> constructor TArrayEnumerator.Create(a: pointer);
> begin
> end;
>
> function TArrayEnumerator.MoveNext: Boolean;
> begin
> end;
>
> var
> arr: TRec;
> value: integer;
> begin
> for value in arr do // <<<< ERROR: Cannot find an enumerator for the
> type "TRec"
> begin
> end;
> end.
>
>
> Regards,
> Ryan Joseph
>
> _______________________________________________
> fpc-pascal maillist - fpc-pascal@lists.freepascal.org
> http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
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