This is my impressionistic non-canonical irregular Clojuresque-Erlangish notes on Lambda Jam conference which took place in Chicago on July 8–10, 2013. These notes are pretty long, and I don’t split them on purpose. If you read them all, you should become overwhelmed and overloaded with the information. Only this way you can feel the same I felt on the last day of the conference :)

After working on Sleeping Barber problem at Coding Dojo I decided to implement it in Erlang. Because Erlang is the perfect language for these sorts of problems, many people have alredy solved it in many different ways. I found at least three groups of solutions: 1) direct implementation using message passing between processes, 2) OTP solution using gen_server, and 3) something resembling object-oriented approach.

Strangely enough, I didn’t see any solution based on FSM. That is odd because this is the first thing coming to my mind when I hear this problem. To fill the gap, I’m going to solve it using gen_fsm, which is a standard OTP behaviour for FSM.

Rod Johnson, creator of Spring, programmer that became entrepreneur:

One thing I think that you really need to be careful of as well, particularly if you, like me, are a programmer, is don’t get carried away writing code. Typically in my experience anyone who is a good programmer is pretty passionate about it, love writing code, get addicted to the process of writing code, fell pretty good about their code basis. As soon as you get down that path you are not thinking straight anymore and now you are increasing your emotional investment, you are having lots of fun writing interesting code and you are no longer in a place mentally where you are going to be trying to find some reason that you shouldn’t write that code. That has been a big lesson for me that the quicker I get to coding, the longer it takes me to ask the kind of questions I should ask upfront.

Linus Torvalds, creator of Linux, programmer that still programs:

I’m interested in programming. When business started happening, I didn’t get into this for the business side. I wanted to do programming. When other people started selling Linux, I said “Yes! Now I can avoid caring about that side too.”

I never had to deal with single business related thing in Linux ever. Seriously, I had to deal with lot of other things but business related things… I got queries and I just said “I don’t care.”

The main guest at today’s MostlyErlang podcast is Joe Armstrong, the co-inventor of Erlang, a wise man, and a brilliant speaker. I listened to the podcast few times, and every time enjoyed it. I highly recommend it to all programmers regardless whether they are using Erlang or not.

While we are waiting for the oficial transcript, this post provides some highlights. I put here the quotes I found particularly interesting or funny.

Concurrency

I’ve got a blog on my GitHub, and I thouhgt I’d put two different types of articles there and see what the response is. One theme I’m pursuing is “explaining to 5-year-old” theme, and the other is “technically complicated” theme.

Then he describes the “concurrency vs parallelism” picture for 5 y.o.

That blog entry got 25,000 people read it, and they got 10 responses and quite a lot of criticism actually from people who know what concurrency and parallelism is. And then I compare it to some other articles I’ve written that technically deeper. There you got only few hundred people read it.

I noticed it too. All those people, who responded with long blogs about concurrency, missed the point: This picture was for kids, and for kids it’s a pretty good picture. Adults should go and read the technical papers, but they didn’t.

Barbara Liskov in her keynote presentation:

I’m a little dismayed what’s happened in programming languages. And the reason I’m dismayed is because on the one hand we have the programming languages that experts use — I’m thinking of Java and C# but you can name bunch of others. And the problem with these languages is — they are powerful, you can build big systems in them — but they aren’t very good for beginners. And what happens in MIT, and I think this is happening across the US anyway, is the people are no longer using those languages in their introductory programming language courses, because the amount of craft you have to go through in order to write the little print-loop is just too much, and the students just get lost in the process. So they’ve been switching to languages like Python.

Python is very simple and nice when you start to use it. But you don’t get too far down the road, if you me, before you discover it has no data abstraction at all. That’s not good because big programs require modularity and encapsulation, and you’d like the language that supports that. So my question is: Can we find a language that will work for both communities? And the reason it matters is because a lot of kids start off programming in their first programming language and that’s it. They may have to change eventually, but they are building huge systems in languages that are really ill-suited for this. So it would be good if the language they started off with is the one they can grow with, and would be good for building big programs as well as small ones.