> both look up methods by name in a hash table and then call them.

Except Ruby doesn't? cue `method_missing`. If you take only trivial examples you're not going to see much difference, this starts to show when you involve more advanced situations e.g with inheritance, and then you're drilling into singleton classes.

> Ruby immediately calls the method once it's found, whereas Python (generally) doesn't - instead it returns a binding to be called later

Again incorrect, `foo.bar` in Ruby and Python are two very fundamentally different things.

Python returns a binding to a method because it's an attribute accessor; when you throw inheritance into the mix it ends up that that attribute is inherited from the parent class, bound to the instance (which really in python means pass `self` as first argument), and - schematically - adding `()` after that ends up calling that bound method. If there's no attribute that's a no method error. It's all very C-ish and make believe, barely a notch above Go structs and their functions. The closest parallel in Ruby would be `foo.method(:bar).call()`

By contrast Ruby is going to send the :bar message along the inheritance chain, and if someone can respond it's going to invoke the responder's code, and surprise surprise method_missing happens only if it has exhausted inheritance but it's itself a method-slash-message; Oh and by the way the message passing is naturally so lazy that you can actually modify the inheritance chain -in flight- and inject a parent responder right before calling `super`. The whole notion of `binding` is a very concrete construct, way more rich that simply "hey I'm passing self as first argument". It becomes even more strange to "C&al. folks" when you start to involve singleton classes and start to realise weird things like Ruby classes are merely instances of the class Class and it's all instance turtles all the way down and all stupidly simple but you gotta have to wrap your head around it.

I surmise that so many differences and surprises have with Ruby are because most languages have some ALGOL legacy and Ruby is a conceptual heir to Smalltalk (and LISP†); the whole concept of open classes being another one: nothing is ever "finished" in Ruby!

Most of the time you don't have to care about these differences, until you do.

† While code isn't quite S-expr data in Ruby, there are more than enough first-class facilities that you can create and inject code entirely dynamically without resorting to `eval`ing strings.

Nice summary. I've been using Ruby both professionally and not for going on 20 years and I just today learned about singleton_class when attempting to build something like Rails' view helpers from first principles.

Thanks. I've been trying to put these bits in a succinct format:

https://lloeki.github.io/illustrated-ruby/

Each chapter kind of builds up on the previous one. It's still WIP and far from complete but what's there has helped me onboard a few people to Ruby already.

You might be interested in the Classes and Ancestry chapters.