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I always thought I understood how OOP works (and I have been using it for years), but sometimes I realize some concepts are still not so clear to me. I just came across this question about method visibility in PHP. The accepted answer explains that a private method cannot be overridden by a child class in PHP. Okay, that makes sense. However, the example made me think about the internal inheritance mechanism in PHP, and the way $this behaves on inherited methods. Consider this code ( example from the PHP Manual , also included in the question mentioned above): class Bar { public function test(

I have been confused about this for a while, even despite reading the Scala Style Guide - Method Invocation several times. I want to be able to call this method def foldRVL[A,B](l: List[A], z: B)(f: (A, B) => B) = //"Right-Via-Left" l.reverse.foldLeft(z)((a, b) => f(b, a)) using dot notation like this List(1,2,3).foldRVL(0)(_ + _) . And not like this: foldRVL(List(1,2,3), 0)(_ + _) . Also, sometimes I've seen code that shows methods that actually either takes zero parameters in their signature, or one fewer parameters than I would expect them to take, and still properly take a parameter using

Oracle reference doesn't tell about best practice of this keyword while we overload constructors. Can anyone suggest the best practice for it? Option 1: delegate to another constructor public class A { private int x, y, z, p; public A() { this(1,1,1,1); } public A(int x, int y, int z, int p) { this.x = x; this.y = y; this.z = z; this.p = p; } } and Option 2: set each field rather than delegating public class A { private int x, y, z, p; public A() { this.x = 1; this.y = 1; this.z = 1; this.p = 1; } public A(int x, int y, int z, int p) { this.x = x; this.y = y; this.z = z; this.p = p; } } The

"The this keyword always refers to the object that the containing function is a method of." Great, sounds simple enough, but here's what I'm wondering about... For example: function func1() { function func2() { alert(this == window); // true } func2(); alert(this == window); // true } func1.func3 = function () { alert(this == window); // false alert(this == func1); // true }; func1(); func1.func3(); Now, since func1 is actually a method of the global ( window ) object (a function object assigned to the property func1 of the global object) it makes sense that this inside func1 refers to the