After Dan’s post, we had a great discussion on reddit that was not a religious discussion, but a “civil and thought-provoking” discussion. And that, in my mind, is the greatest power of Clojure.

And The Winner is…

Yes, we have not established which is better mount or component, but that was never the point. The great summary of the discussion was a realization that @yogthos and @weavejester made at the end:

“Overall, it sounds like both approaches are actually fairly similar: Mount uses namespaces and vars where Component uses records and protocols, but the purpose is broadly the same.”

This is interesting for two major reasons:

* It advocates the proper usage of Component with using protocols over records/components

* It draws a clear parallel between Mount and Component, so it is a lot easier to choose which one fits your coding style / (formal vs. simple) mindset.

Libraries vs. Frameworks

Since I am obviously biased towards Mount :)..

Component manages protocols and records, and in order to do that it requires a whole app buyin, which makes it a framework. Mount does not need to manage namespaces and vars, since it is very well managed by the Clojure Compiler. Which makes it a library, which I prefer. You may not, and I respect that.

Math vs. Music

Another thing I keep noticing is that “formally” inclined people prefer records and protocols for many solutions, and for them it is easier to reason about applications since it fits better into the formal mindset.

What I disagree with is equating “more formal” with simpler. It is simpler for a formal mindset, yes, but it is not simpler for me. Explicit formalism complects things for my mindset. I do not believe there is an objective truth here, since we are just different. But I believe Clojure has both: which allows for both mindsets to coexist.

What I like protocols for is an optimized dynamic dispatch, creating libraries (which use protocols internally), and a way to tame the expression problem if and when it arises. Protocols make it simple for me.

“Frogs All Look The Same”

And to make it more interesting, I am currently on the train going back to Philly from the great NYC Lisp meetup, where Gerald Sussman presented a way to write systems that evolve and expand to handle any future functionality that is thrown at them (“extensible generics”).

He drew an interesting parallel between software systems and biology saying that “many biological mutations are fatal, but as a result we end up with extremely robust systems“, doesn’t sound very formal to me ;)

Tags: clojure, component, formalism, mount, music