Cocoa (OS X) vs. Yesod vs. webapp2

Much of Cocoa is implemented in Objective-C, an object-oriented language that is compiled to run at incredible speed, yet employs a truly dynamic runtime making it uniquely flexible. Because Objective-C is a superset of C, it is easy to mix C and even C++ into your Cocoa applications.

Yesod believes in the philosophy of making the compiler your ally, not your enemy. We use the type system to enforce as much as possible, from generating proper links, to avoiding XSS attacks, to dealing with character encoding issues. In general, if your code compiles, it works. And instead of declaring types everywhere you let the compiler figure them out for you with type inference.

webapp2 is a simple. it follows the simplicity of webapp, but improves it in some ways: it adds better URI routing and exception handling, a full featured response object and a more flexible dispatching mechanism.