Generic number math without generics

program GenericMath;

{$APPTYPE CONSOLE}

uses
  SysUtils;

procedure AddInt32(const arr: TArray<Integer>; index: Integer; var result: UInt64);
begin
  Inc(result, arr[index]);
end;

procedure AddUInt32(const arr: TArray<Cardinal>; index: Integer; var result: UInt64);
begin
  Inc(result, arr[index]);
end;

procedure AddExtended(const arr: TArray<Extended>; index: Integer; var result: Extended);
begin
  result := result + arr[index];
end;

procedure SumArray(const arr: Pointer; addProc: Pointer; var result); //inline;
type
  TAddProc = procedure(const arr; index: Integer; var result);
var
  i: Integer;
begin
  for i := 0 to High(TArray<Byte>(arr)) do
    TAddProc(addProc)(arr^, i, result);
end;

function Sum(const arr: TArray<Integer>): UInt64; overload; inline;
begin
  Result := 0;
  SumArray(arr, @AddInt32, Result);
end;

function Sum(const arr: TArray<Cardinal>): UInt64; overload;
begin
  Result := 0;
  SumArray(arr, @AddUInt32, Result);
end;

function Sum(const arr: TArray<Extended>): Extended; overload;
begin
  Result := 0;
  SumArray(arr, @AddExtended, Result);
end;

var
  arr1: TArray<Integer>;
  arr2: TArray<Extended>;
  sum1: Integer;
  sum2: Extended;
begin
  arr1 := TArray<Integer>.Create(1, 2, 3, 4, 5, 6, 7, 8, 9);
  arr2 := TArray<Extended>.Create(1.1, 2.2, 3.3, 4.4, 5.5, 6.6, 7.7, 8.8, 9.9);
  sum1 := Sum(arr1);
  sum2 := Sum(arr2);
  Writeln(sum1);
  Writeln(sum2);
  Readln;
end.