Overload () operator in Python
You can make an object callable by implementing the __call__ method: class FunctionLike(object): def __call__(self, a): print(“I got called with {!r}!”.format(a)) fn = FunctionLike() fn(10) # –> I got called with 10!
operator-overloading
What is “Best Practice” For Comparing Two Instances of a Reference Type?
Implementing equality in .NET correctly, efficiently and without code duplication is hard. Specifically, for reference types with value semantics (i.e. immutable types that treat equvialence as equality), you should implement the System.IEquatable<T> interface, and you should implement all the different operations (Equals, GetHashCode and ==, !=). As an example, here’s a class implementing value equality: … Read more
How arrow-> operator overloading works internally in c++?
The operator-> has special semantics in the language in that, when overloaded, it reapplies itself to the result. While the rest of the operators are applied only once, operator-> will be applied by the compiler as many times as needed to get to a raw pointer and once more to access the memory referred by … Read more
difference between global operator and member operator
One reason to use non-member operators (typically declared as friends) is because the left-hand side is the one that does the operation. Obj::operator+ is fine for: obj + 2 but for: 2 + obj it won’t work. For this, you need something like: class Obj { friend Obj operator+(const Obj& lhs, int i); friend Obj … Read more
Override the Equivalence Comparison in Javascript
That is because the == operator doesn’t compare only primitives, therefore doesn’t call the valueOf() function. Other operators you used do work with primitives only. I’m afraid you cannot achieve such thing in Javascript. See http://www.2ality.com/2011/12/fake-operator-overloading.html for some more details.
How do I prevent a class from being allocated via the ‘new’ operator? (I’d like to ensure my RAII class is always allocated on the stack.)
All you need to do is declare the class’ new operator private: class X { private: // Prevent heap allocation void * operator new (size_t); void * operator new[] (size_t); void operator delete (void *); void operator delete[] (void*); // … // The rest of the implementation for X // … }; Making ‘operator new’ … Read more
C++: Convenient way to access operator[] from within class?
(*this)[bar]; works fine for me.
Making operator
The problem with this setup is that the operator<< you defined above is a free function, which can’t be virtual (it has no receiver object). In order to make the function virtual, it must be defined as a member of some class, which is problematic here because if you define operator<< as a member of … Read more
Why doesn’t `std::initializer_list` provide a subscript operator?
According to Bjarne Stroustrup in Section 17.3.4.2 (p. 497) of The C++ Programming Language, 4th Edition: Unfortunately, initializer_list doesn’t provide subscripting. No further reason is given. My guess is that it’s one of these reasons: it’s an omission, or because the initializer_list class is implemented with an array and you’d have to do bounds checking … Read more
Why can overloaded operators not be defined as static members of a class?
Because there isn’t an obvious syntax to call such an operator, which would mean we’d have to make up something. Consider the following variables: X x1; X x2; Now, let’s pretend for a moment that we’re using normal member functions instead of operators – let’s say I changed operator+ to plus in your example. Each … Read more