metaclass

In the following example, the newly created subclass ends up being the metaclass __module__ rather than the parent classes' module. I've only seen this happen when using ABCMeta so it could be something specific to that module, anyone know what might be happening? In [1]: from abc import ABCMeta In [2]: class test(metaclass=ABCMeta): ...: pass ...: In [3]: newclass = type('newclass', (test,), {}) In [4]: newclass.__module__ Out[4]: 'abc' The behavior I want happens when I define the subclass in the more standard way: In [5]: class subtest(test): ...: pass ...: In [6]: subtest.__module__ Out[6]

I've been trying to learn about metaclasses in Python. I get the main idea, but I can't seem to activate the mechanism. As I understand it, you can specify M to be as the metaclass when constructing a class K by setting __metaclass__ to M at the global or class level. To test this out, I wrote the following program: p = print class M(type): def __init__(*args): type.__init__(*args) print("The rain in Spain") p(1) class ClassMeta: __metaclass__ = M p(2) __metaclass__ = M class GlobalMeta: pass p(3) M('NotMeta2', (), {}) p(4) However, when I run it, I get the following output: C:\Documents and

I'm trying to implement a basic object-oriented ANSI C runtime and using Objective-C as a guide. They're seems to be three parts. A Class Description, Class Interface, and Class Implementation. In order for the Class Interface to be instantiated, the familiar method of using the Class object to instantiate one's object can only happen if the runtime has already instantiated your class object using the class description. So are all Class definitions allocated statically at first run to provide the ability to instantiate using the Class object? Or if they are allocated dynamically (on initial

This question already has an answer here: How to create a custom string representation for a class object? 5 answers Can I define a __repr__ for a class rather than an instance? For example, I'm trying to do this class A(object): @classmethod def __repr__(cls): return 'My class %s' % cls What I get is In [58]: a=A() In [59]: a Out[59]: My class <class '__main__.A'> In [60]: A Out[60]: __main__.A I'm trying to get the output of line 60 to look like "My Class A", not for the instance a. The reason I want to do this is I'm generating a lot of classes using Python's metaclass. And I want a more

I have a following script: task myTask {} class Person { Person() { Person instance = this println this.metaClass.class.name println this.getMetaClass().class.name println instance.metaClass.class.name println instance.getMetaClass().class.name } } Person person = new Person() And the output is : groovy.lang.MetaClassImpl groovy.lang.MetaClassImpl org.codehaus.groovy.runtime.HandleMetaClass org.codehaus.groovy.runtime.HandleMetaClass Can anyone explain to me what is going on? Thanks in advance. Take a look at this class , class Person { def a, b Person() { a = this b = this println "this $this

In the vein of... @implementation MyClass - (id) objectForKeyedSubscript:(id)k { return [self something:k]; } Is it also possible to "subscript" Class objects? I too, am about to find out, with you.. but thought I would post this question as I tested it out, myself... + (id) objectForKeyedSubscript:(id)k { return [self.shared something:k]; } And alas.. it is not... id x = MyClass[@"document"]; error: unexpected interface name 'MyClass': expected expression But why, Daddy? Class ' sure get the short end of NSObject 's stick, if you ask me . Alex Gray Josh Caswell's comment pointed out the

I have several objects of different kinds (different function names, different signatures) and I monkey patch them to have a common way to access them from different functions. Briefly, there is a dispatcher that takes the objects that I want to patch and depending on the object type it calls different patcher. A patcher will add methods to the object: def patcher_of_some_type(object): def target(self, value): # do something and call self methods object.target = types.MethodType(target, object) # many more of these As the program grows more complicated making a wrapper around the object (or