No, it's not. He's just showcasing the simplicity of bottle.py

Not as bad as those examples you just saw, but as others already said, those are mainly illustrative. Beyond that, it's a matter of template engines and most frameworks allow you to choose one.

Generally you won't see PHP/JSP levels of code, but the more popular engines do allow quite a bit of logic, i.e. don't adhere to StringTemplate-level purity[1].

[1]: http://www.cs.usfca.edu/~parrt/papers/mvc.templates.pdf

Those micro-frameworks are designed to make a hello-world app very short and to the point. There's one (aspen.io) that uses the ^L character as a section separator to achieve maximum concision: setup, request handling, optional template. No space is wasted on function blocks or explicit registration calls.

PHP is about mixing it with other stuff (hence the <?php tag). So PHP smells by definition :-)

This is a simple example to make a point about the simplicity of using bottle, a python micro-framework contained in a single file with all the stuff you need for simple web projects (like routing, templates, various utilities and even a test server).