monkeypatching

I want to generate human-readable HTML and CSS code (properly indented) preprocessed by the Django template system for my standalone application. I've modified the render method from the NodeList class found in the django.template.base module. My code seems to work properly, but I'm using monkey-patching to replace the old render method. Is there a more elegant way that does not use monkey-patching in this case? Or maybe monkey-patching is the best way here? My code looks like this: ''' This module monkey-patches Django template system to preserve indentation when rendering templates. '''

It is very convenient in numpy to use the .T attribute to get a transposed version of an ndarray . However, there is no similar way to get the conjugate transpose. Numpy's matrix class has the .H operator, but not ndarray. Because I like readable code, and because I'm too lazy to always write .conj().T , I would like the .H property to always be available to me. How can I add this feature? Is it possible to add it so that it is brainlessly available every time numpy is imported? (A similar question could by asked about the .I inverse operator.) You can subclass the ndarray object like: from

I'm monkey-patching a Rails engine with something like: SomeClass.class_eval do # ... end The first time I hit the web site, on development mode at least, it works, but the second time it's like my patch never existed. I presume it's Rails auto-reloading the engine (which is installed in vendor/) and not reloading my code. This is Rails 2.3. Any ideas how to do it so that my code also gets reloaded? EDIT: This solution only works for Rails 3+ since it's dependent on some functionality in Rails::Railtie. Put this code in an initializer. This question is quite old, but here's a solution I found:

How can I extend a builtin class in python? I would like to add a method to the str class. I've done some searching but all I'm finding is older posts, I'm hoping someone knows of something newer. S.Lott Just subclass the type >>> class X(str): ... def my_method(self): ... return int(self) ... >>> s = X("Hi Mom") >>> s.lower() 'hi mom' >>> s.my_method() Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 3, in my_method ValueError: invalid literal for int() with base 10: 'Hi Mom' >>> z = X("271828") >>> z.lower() '271828' >>> z.my_method() 271828 One way

I don't want to discuss the merits of this approach, just if it is possible. I believe the answer to be "no". But maybe someone will surprise me! Imagine you have a core widget class. It has a method calculateHeight() , that returns a height. The height is too big - this result in buttons (say) that are too big. You can extend DefaultWidget to create your own NiceWidget, and implement your own calculateHeight() to return a nicer size. Now a library class WindowDisplayFactory, instantiates DefaultWidget in a fairly complex method. You would like it to use your NiceWidget. The factory class's

Some languages like Ruby and JavaScript have open classes which allow you to modify interfaces of even core classes like numbers, strings, arrays, etc. Obviously doing so could confuse others who are familiar with the API but is there a good reason to avoid it otherwise, assuming that you are adding to the interface and not changing existing behavior? For example, it might be nice to add a an Array.map implementation to web browsers which don't implement ECMAScript 5th edition (and if you don't need all of jQuery). Or your Ruby arrays might benefit from a "sum" convenience method which uses

I'm using the Devise authentication gem in my Rails project, and I want to change the keys it's using in flash alerts. (Devise uses :notice and :alert flash keys, but I want to change them to :success and :error so that I can display nice green/red boxes with Bootstrap .) So I want to be able to somehow override the set_flash_message method in DeviseController . Here's the new method: def set_flash_message(key, kind, options = {}) if key == 'alert' key = 'error' elsif key == 'notice' key = 'success' end message = find_message(kind, options) flash[key] = message if message.present? end But I