向通用TArray类添加非类函数 [英] Adding non class functions to generic TArray class

问题描述

在 System.Generics.Collections 中， TArray 类型仅具有类函数.

In System.Generics.Collections, the TArray type has class functions only.

例如:

class procedure Sort<T>(var Values: array of T); overload; static;

这意味着唯一接受的语法如下:

This implies the only accepted syntax is the following:

var
  Arr : TArray<integer>;
begin
  SetLength(Arr, 2);
  Arr[0] := 5;
  Arr[1] := 3;

  TArray.Sort<integer>(Arr);
end;

我想定义一个对象的函数，以便使用以下语法对通用数组的值进行排序:

I would like to define an object's function in order to sort the values of the generic array using the following syntax:

var
  Arr : TArray<integer>;
begin
  SetLength(Arr, 2);
  Arr[0] := 5;
  Arr[1] := 3;

  Arr.Sort();
end;

推荐答案

您可以为非通用动态数组或完全专用的通用动态数组定义帮助程序.例如，您可以编写:

You can define helpers for non-generic dynamic arrays, or for fully specialized generic dynamic arrays. For instance, you can write:

type
  TMyArray1 = array of Integer;
  TMyArray2 = TArray<Integer>;

  TMyArrayHelper1 = record helper for TMyArray1
  end;
  TMyArrayHelper2 = record helper for TMyArray2
  end;
  TMyArrayHelper3 = record helper for TArray<Integer>
  end;

这允许您将方法添加到此类数组的范围.

This allows you to add methods to the scope of such arrays.

所以你可以写

type
  TIntegerArrayHelper = record helper for TArray<Integer>
    procedure Sort;
  end;

procedure TIntegerArrayHelper.Sort;
begin
  TArray.Sort<Integer>(Self);
end;

但是，您不能做的是写:

However, what you cannot do is write:

  TMyArrayHelper<T> = record helper for TArray<T>
  end;

编译器根本不支持通用帮助器.

The compiler simply does not support generic helpers.

在我看来，这些都不值得，只需致电:

None of this is worthwhile in my view, just call:

TArray.Sort<T>()

直接.在我看来，添加一个记录助手，并为每种希望支持的元素类型创建一个助手，这似乎并不足以证明返回的合理性.

directly. Adding a record helper, and having to make one for each element type that you wish to support, seems to me like a cost that does not justify the return.

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