基于具体类型的泛型类的条件行为

问题描述

由于我的问题从可能并不完全清楚，我没有得到答案我想，我会尝试以更一般的方式来制定它：

Since my question from yesterday was perhaps not completely clear and I did not get the answer I wanted, I will try to formulate it in a more general way:

有没有办法根据实例化的泛型类型的实际类型来实现特殊行为，阐述条件陈述或使用某种专业化？伪代码：

Is there a way to implement special behaviour based on the actual type of an instantiated generic type either using explict conditional statements or using some kind of specialization? Pseudocode:

TGenericType <T> = class
  function Func : Integer;
end;
...
function TGenericType <T>.Func : Integer;
begin
  if (T = String) then Exit (0);
  if (T is class) then Exit (1);
end;
...
function TGenericType <T : class>.Func : Integer;
begin
Result := 1;
end;
function TGenericType <String>.Func : Integer;
begin
Result := 0;
end;

推荐答案

您可以回到RTTI，使用 TypeInfo（T）= TypeInfo（string）。要测试某些东西是否是一个类，可以使用类似于 PTypeInfo（TypeInfo（T））^。Kind = tkClass 。

You can fall back to RTTI, by using TypeInfo(T) = TypeInfo(string). To test to see if something is a class, you could use something like PTypeInfo(TypeInfo(T))^.Kind = tkClass.

在 TypInfo中定义了 PTypeInfo 类型和 tkClass 枚举成员单位。

The PTypeInfo type and tkClass enumeration member are defined in the TypInfo unit.

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