[Screencast] Elixir: Object Orientation and charming syntax on top of Erlang

http://blog.plataformatec.com.br/2011/03/screencast-elixir-simple-object-orientation-and-charming-syntax-on-top-of-erlang/

by josevalim • 15 years ago

34 11 15 years ago

blog.plataformatec.com.br

edw2• 15 years ago

Eval?! In all my years of writing Scheme, Javascript, and Clojure, I don't think I've ever written "eval" without later regretting it.

josevalim5• 15 years ago

It is "module_eval", which is not the same eval as Scheme, Javascript or Clojure. It means to evaluate the code in the context of a given module, allowing you to dynamically define new methods. The old regular eval is also available.

edw2• 15 years ago

Ah, is this the "monkey patching" I've heard (so many bad things) about? Or something closer to Objective C's protocols and Java's interfaces?

Ezku2• 15 years ago

This definitely makes Erlang more approachable for me - I've managed to develop a strong dislike for the syntaxes in a lot of functional languages including Lisp and Haskell. From my perspective, the syntactic choices documented in https://github.com/josevalim/elixir seem rather reasonable on the whole, but functions are a tad odd. Is there any specific reason why it's "-> (x, y) x + y"? I always thought the motive for the arrow notation in the form "(x, y) -> x + y" was an obvious cognitive mapping into "x and y becomes x + y". Seems a bit bass ackwards as it is. I also have a minor issue with the atom prefix (to me : would have been more distinctive), but that's admittedly more of a personal thing.

josevalim5• 15 years ago

I'm glad that you found the syntax reasonable as a whole. :D Regarding to functions and atoms, their syntax choices are a trade-off. If I have "(x, y) -> x + y" for functions, I need explicit parens when invoking a method (otherwise we will have ambiguity), so I prefer to have this flexibility on method invocations. A similar choice happened to atoms. As I preferred to save ":" for dicts, as in { x: y }, the syntax would get very confusing if I allowed: { :x: :y }. That said, I have chosen 'atom, which is common in some Lisp dialects.

Ezku2• 15 years ago

Having now read the entirety of the readme, I'm left a bit unclear on the object model's semantics. If I declare a mixin in an object, those become class methods? Whereas declaring a prototype results in instance methods? Also, "set_ivar" seems like a needlessly complex and obscure statement.

davidw• 15 years ago

Wow, looks cool! How does it compare with, say, Reia, which is very similar?

josevalim5• 15 years ago

There is one key difference right now: Elixir is much better documented. Elixir also has a well defined Object Model which helps a lot understanding what is going on and makes meta programming easier. I also find Elixir data structure's syntax closer to Erlang's, but that is not necessarily something positive or negative.

[Screencast] Elixir: Object Orientation and charming syntax on top of Erlang

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