arrays - 我可以定义不同类型的数组类型吗？

Question

我想定义一个由不同类型组成的数组类型，例如String、Integer、Boolean、 Double 等，但没有对象、结构或任何此类性质的东西。然后我想使用这种类型作为函数参数，例如......

type
  TMyArray = array of ...?...;

function GetSomething(const Input: TMyArray): String;
var
  X: Integer;
begin
  for X:= 0 to Length(Input) - 1 do begin
    //Identify type and handle accordingly...
    //Serialize data for the result...

  end;
end;

并像...一样使用它

Variable:= GetSomething(['some string', 123, 'something else', 12.3, false]);

那么，在迭代这样的数组时如何识别每个元素的类型？

我很确定这是可能的，但甚至不知道要搜索什么术语。我该怎么做？

我是否必须将其定义为变体数组？或者有没有办法准确定义数组接受哪些类型？

编辑

不改变任何问题，但在RRUZ回答之后，我发现an intriguing article关于以不同方式执行此操作时的性能...

Answer 1

如果您的 Delphi 版本支持 RTTI，您可以使用 TValue 数组和 Kind 属性，如下所示。

{$APPTYPE CONSOLE}


uses
  System.TypInfo,
  System.Rtti,
  System.SysUtils;


function GetSomething(const Input: array of TValue): String;
var
  X: Integer;
  LValue : TValue;
begin
  for LValue in Input  do begin
     case LValue.Kind of
       tkUnknown: Writeln('Unknown');
       tkInteger:  Writeln(Format('The Kind of the element is Integer and the value is %d',[LValue.AsInteger]));
       tkChar: Writeln('Char');
       tkEnumeration: if LValue.TypeInfo=TypeInfo(Boolean) then Writeln(Format('The Kind of the element is Boolean and the value is %s',[BoolToStr(LValue.AsBoolean, True)]));
       tkFloat: Writeln(Format('The Kind of the element is Float and the value is %n',[LValue.AsExtended]));
       tkString: Writeln('String');
       tkSet: Writeln('Set');
       tkClass: Writeln('Class');
       tkMethod:Writeln('method');
       tkWChar: Writeln('WChar');
       tkLString: Writeln('String');
       tkWString: Writeln('String');
       tkVariant: Writeln('Variant');
       tkArray: Writeln('Array');
       tkRecord: Writeln('Record');
       tkInterface: Writeln('Interface');
       tkInt64: Writeln('Int64');
       tkDynArray: Writeln('DynArray');
       tkUString:  Writeln(Format('The Kind of the element is String and the value is %s',[LValue.AsString]));
       tkClassRef:  Writeln('Class Ref');
       tkPointer: Writeln('Pointer');
       tkProcedure:  Writeln('procedure');
     end;
  end;
end;

begin
  try
    GetSomething(['some string', 123, 'something else', 12.3, false]);
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
  Readln;
end.

另一个选项是使用const数组

{$APPTYPE CONSOLE}

uses
  SysUtils;


procedure GetSomething(const Input: array of const);
var
  LIndex: Integer;
begin
  for LIndex := Low(Input) to High(Input) do
  begin
    case Input[LIndex].VType of
      vtWideString: Writeln('WideString = ''', WideString(Input[LIndex].VWideChar), '''');
      vtInt64: Writeln('Int64 = ', Input[LIndex].VInt64^);
      vtCurrency: Writeln('Currency = ', CurrToStr(Input[LIndex].VCurrency^));
      vtInteger: Writeln('Integer = ', Input[LIndex].VInteger);
      vtBoolean: Writeln('Boolean = ', BoolToStr(Input[LIndex].VBoolean, True));
      vtChar: Writeln('Char = ''', Input[LIndex].VChar, '''');
      vtExtended: Writeln('Extended = ', FloatToStr(Input[LIndex].VExtended^));
      vtString: Writeln('ShortString = ''', Input[LIndex].VString^, '''');
      vtPChar: Writeln('PChar = ''', Input[LIndex].VPChar, '''');
      vtAnsiString: Writeln('AnsiString = ''', Ansistring(Input[LIndex].VAnsiString), '''');
      vtWideChar: Writeln('WideChar = ''', Input[LIndex].VWideChar, '''');
      vtPWideChar: Writeln('PWideChar = ''', Input[LIndex].VPWideChar, '''');
      vtUnicodeString : Writeln('UnicodeString = ''', string(Input[LIndex].VUnicodeString), '''');
    else
      Writeln('Unsupported');
    end;
  end;
end;

begin
  try
    GetSomething(['some string', 123, 'something else', 12.3, false]);
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
  Readln;
end.