Ruby and other languages (such as Smalltalk and Objective-C) prefer the term “message passing”, whereas Java and C++ prefer “method invocation”. That is, the “Java way” is to call a method on an object — running code in the context of an object — whereas the “Ruby way” is to send an object a message, … Read more
There is no generic way for a function to refer to itself. Consider using a decorator instead. If all you want as you indicated was to print information about the function that can be done easily with a decorator: from functools import wraps def showinfo(f): @wraps(f) def wrapper(*args, **kwds): print(f.__name__, f.__hash__) return f(*args, **kwds) return … Read more
This is because attributes/associations are actually methods(getters/setters) and not local variables. When you state “parent = value” Ruby assumes you want to assign the value to the local variable parent. Somewhere up the stack there’s a setter method “def parent=” and to call that you must use “self.parent = ” to tell ruby that you … Read more
self points to the class in which it is written. So, if your getInstance method is in a class name MyClass, the following line : self::$_instance = new self(); Will do the same as : self::$_instance = new MyClass(); Edit : a bit more information, after the comments. If you have two classes that extend … Read more
See this thread http://www.cocoabuilder.com/archive/cocoa/241465-iphone-why-can-a-uitextfield-be-its-own-delegate.html#241505 Basically, the reason for the “freeze” when you click on your UITextField with itself as a delegate is that respondsToSelector is calling itself -> infinite recursion. UITextField is unique AFAIK. You can usually use a class as its own delegate with no particular problems. For UITextField you must create an actual … Read more
In Python, this: my_object.method(“foo”) … is syntactic sugar, which the interpreter translates behind the scenes into: MyClass.method(my_object, “foo”) … which, as you can see, does indeed have two arguments – it’s just that the first one is implicit, from the point of view of the caller. This is because most methods do some work with … Read more
In Python, this: my_object.method(“foo”) …is syntactic sugar, which the interpreter translates behind the scenes into: MyClass.method(my_object, “foo”) …which, as you can see, does indeed have two arguments – it’s just that the first one is implicit, from the point of view of the caller. This is because most methods do some work with the object … Read more
The reason you need to use self. is because Python does not use special syntax to refer to instance attributes. Python decided to do methods in a way that makes the instance to which the method belongs be passed automatically, but not received automatically: the first parameter of methods is the instance the method is … Read more
In addition to what others said (especially PeterSO and dskinner—in his comment to the Peter’s answer), note several important things: You can call a method like a simple function In Go, you can call any method function not as a method on a receiver but rather as a regular function—simply by qualifying its name with … Read more
self refers to the instance of the current class that you are working in, and yes, it is analagous to this in Java. You use it if you want to perform an operation on the current instance of that class. For example, if you are writing an instance method on a class, and you want … Read more