function - 如何将类型传递给在内部构造函数 ("this"等效项中调用的函数)？

Question

我有一个在不同结构中运行的函数，如何知道我的函数在哪个结构中运行。 示例:

function foo()
#here I need to find out the name of the struct  this function runs (which constructor called it) 
   in, A or B
end



  struct A
    arg
    function A(arg)
        foo(arg)
      return new(arg)
     end
   end



 struct B
    arg
   function B(arg)
        foo(arg)
      return new(arg)
    end
 end

Answer 1

在内部构造函数中使用 new 创建的实例来分派(dispatch) foo。当然，您可以自由自定义 foo 来做更多不同的事情，而不仅仅是打印类型的符号。

foo(t::T) where T = Symbol(T)

struct A
  function A()
    instance = new()
    println("foo was called in ", foo(instance))
    return instance
  end
end

struct B
  function B()
    instance = new()
    println("foo was called in ", foo(instance))
    return instance
  end
end

A() # prints: foo was called in A
B() # prints: foo was called in B