delphi 运算符重载

2024-01-07 22:59:52

譬如上面的 record 可以这样声明:

type
  TMyRec = record
    name: string;
    age: Word;
    class operator GreaterThan(a,b: TMyRec): Boolean;
  end;

还得有方法的实现(遗憾的是有些不能用 Ctrl+Shift+C 自动建立, 那就复制吧):

class operator TMyRec.GreaterThan(a,b: TMyRec): Boolean; {注意复制后再加上方法名: "TMyRec."}
begin
  Result := a.age > b.age;
end;

Delphi for Win32 只支持 record 类型的运算符重载，而 Delphi .NET 还支持 class 类型的运算符重载
下面是Delphi支持的可重载运算符

运算符类型声明语法应用符号
Implicit 转换 Implicit(a: type): resultType; 隐式转换

Explicit 转换 Explicit(a: type): resultType; 显式转换

负一元运算 Negative(a: type): resultType; -

正一元运算 Positive(a: type): resultType; +

递增一元运算 Inc(a: type): resultType; Inc

递减一元运算 Dec(a: type): resultType; Dec

逻辑非一元运算 LogicalNot(a: type): resultType; not

按位非一元运算 BitwiseNot(a: type): resultType; not

截取一元运算 Trunc(a: type): resultType; Trunc

舍入一元运算 Round(a: type): resultType; Round

等于比较 Equal(a: type; b: type) : Boolean; =

不等于比较 NotEqual(a: type; b: type): Boolean; <>

大于比较 GreaterThan(a: type; b: type) Boolean; >

大于等于比较 GreaterThanOrEqual(a: type; b: type): resultType;>=

小于比较 LessThan(a: type; b: type): resultType; <

小于等于比较 LessThanOrEqual(a: type; b: type): resultType; <=

加二元运算 Add(a: type; b: type): resultType; +

减二元运算 Subtract(a: type; b: type): resultType; -

乘二元运算 Multiply(a: type; b: type): resultType; *

除二元运算 Divide(a: type; b: type): resultType; /

整除二元运算 IntDivide(a: type; b: type): resultType; div

模二元运算 Modulus(a: type; b: type): resultType; mod

左移二元运算 ShiftLeft(a: type; b: type): resultType; shl

右移二元运算 ShiftRight(a: type; b: type): resultType; shr

逻辑与二元运算 LogicalAnd(a: type; b: type): resultType; and

逻辑或二元运算 LogicalOr(a: type; b: type): resultType; or

逻辑异或二元运算 LogicalXor(a: type; b: type): resultType; xor

按位与二元运算 BitwiseAnd(a: type; b: type): resultType; and

按位或二元运算 BitwiseOr(a: type; b: type): resultType; or

按位异或二元运算 BitwiseXor(a: type; b: type): resultType; xor

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