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Overload -> operator to forward member-access through Proxy


Overload -> operator to forward member-access through Proxy

By : user2948353
Date : November 14 2020, 04:51 PM
Any of those help I'm trying to wrap a Python PyObject* in an Object class. In Python, everything is a PyObject*. A list is a PyObject*, and each item in the list is itself a PyObject*. Which could even be another list. etc. , If you can change Object, you may add
code :
class Object {
public:
    // other code
    const Object* operator -> () const { return this; }
    Object* operator -> () { return this; }
};
Object operator->() { return container[key]; }
myObj[42]->myFoo = ...
Proxy proxy = myObj[42];
Object obj = proxy.operator ->();
Object* pobj = obj.operator ->(); // so pobj = &obj;
pobj->myFoo = ...


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Templated operator overload resolution, member vs non-member function

Templated operator overload resolution, member vs non-member function


By : Red Knight
Date : March 29 2020, 07:55 AM
Any of those help Overload resolution adds an additional parameter to a member function just for the purpose of overload resolution:
[over.match.funcs]/2
code :
template<class T>
ostr& ostr::operator<<(ostr&, const T&);    // F1

template<class Stream>
Stream& ::operator<<(Stream&, const xy&);    // F2
ostr& ostr::operator<<(ostr&, const xy&);
ostr& ::    operator<<(ostr&, const xy&);
struct unique_T {};
struct unique_Stream {};
ostr& ostr::operator<<(ostr&, const unique_T&);
ostr& ::    operator<<(unique_Stream&, const xy&);
ostr a0;
unique_T a1; // no reference, no cv-qualifier
::operator<<(a0, a1) // does template argument deduction succeed?

// reminder: signature of ::operator<<
template<class Stream>
Stream& ::operator<<(Stream&, const xy&);
unique_Stream a0;
xy a1;
ostr::operator<<(a0, a1);

// reminder: signature of ostr::operator<<
template<class T>
ostr& ostr::operator<<(ostr&, const T&);
C++ istream operator overload - cant access data member even though declared friend

C++ istream operator overload - cant access data member even though declared friend


By : user2659840
Date : March 29 2020, 07:55 AM
wish helps you I have a class Complex and I'm trying to overload the istream operator >> to allow the user to input a complex number in the form "(a, b)". Below is my header file and my implementation. Right now, I'm getting an error saying that my overloaded >> function can not access the real or imaginary data members because they are inaccessible, even though I declared them as friends in the class header file. Can anyone explain what I'm not seeing? , Your error is here
code :
 friend std::istream &operator>>(std::istream &, const Complex &);
                                              // ^^^^^
 istream &operator>>(istream &in, Complex &operand2)
Overload member access operator

Overload member access operator


By : user3345543
Date : March 29 2020, 07:55 AM
may help you . Is there a way to overload member access operator in python? Example (as it can be a XY problem, I'll provide an example containing what I want to do): , You can try overriding getattr:
code :
class A:
    def __getattr__(self, name):
        if name == "foo":
            return lambda: print("hi")


>>> a = A()
>>> a.foo()
hi
class A:
    def __getattr__(self, name):
        if name == "foo":
            return lambda *args: print(args)


>>> a = A()
>>> a.foo(1, 2, 3)
(1, 2, 3)
Overload operator << for enumerated member of a class in member functions

Overload operator << for enumerated member of a class in member functions


By : user3945939
Date : March 29 2020, 07:55 AM
should help you out How do I overload the << operator for enums that are members of a class. Specifically, I have the following code below: , Here is a simple solution :
Cannot overload operator because cannot access private member declared in class

Cannot overload operator because cannot access private member declared in class


By : Sue Steiner
Date : March 29 2020, 07:55 AM
it fixes the issue I have a class with an operator overload as so: , You have to return a reference.
code :
friend ostream& operator<< (ostream &stream, const Item &item)
//            ^
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