What's all this fuss about Erlang? (2007)

Post by titraprutr » Wed, Jan 25, 2017, 12:34 PM UTC

digitalzombie wrote: post #139

mnd wrote: post #44

Earlier quoted context omitted.

Erlang is a great programming language after one takes the time to understand the principles underlying it and its design. Everything fits very nicely into place. There are definitely things that could be done better, but then that’s the case with most programming languages and technologies after they have accumulated some dust. Elixir on the other hand, in my personal opinion, is a false prophet simply because it lo…

Elixir is prettier than Erlang but it really mess up on certain things. Erlang have pattern matching via function with same name and you can tell if it's a group of pattern matching with semicolon and period. But with Elixir you can't tell it's just def and end. Erlang's: -module(recursive). -export([fac/1]). fac(N) when N == 0 -> 1; fac(N) when N > 0 -> N * fac(N-1). You can tell fac(N) both are in a group of patter…

Post by amelius » Wed, Jan 25, 2017, 1:54 PM UTC

joesb wrote: post #169

amelius wrote: post #168

Earlier quoted context omitted.

> As Erlang requires message passing overhead by design That's Erlang's main weakness. For parallel code, structurally shared data is immensely useful for processes running in the same address space. With Erlang, you have to give that up. OTOH, not having this possibility makes distributing processes to other nodes a lot simpler.

You should be able to share data in Erlang's model, because the data are immutable. You just can't modified the shared data.

Post by ww520 » Wed, Jan 25, 2017, 2:42 PM UTC

BeetleB wrote: post #153

m00x wrote: post #118

Earlier quoted context omitted.

And then you also need to implement mailboxes to receive new data, supervisors to watch the threads and revive them when they fail, initialization methods to get back to the original state, etc. You can trivialize any issue if you ignore all the facts, but it doesn't make your argument have any correctness.

I'm really surprised at the arguing in this thread. Embarrassingly parallel algorithms are trivial in pretty much every language. That is why is embarrassing. >And then you also need to implement mailboxes to receive new data If you did, it is not embarrassingly parallel. You know, a huge amount of parallel work is done in C/C++. It was the language used for multiple parallel algorithms courses in my university. Bein…

Post by BoorishBears » Wed, Jan 25, 2017, 2:45 PM UTC

jknoepfler wrote: post #156

digitalzombie wrote: post #139

Earlier quoted context omitted.

Elixir is prettier than Erlang but it really mess up on certain things. Erlang have pattern matching via function with same name and you can tell if it's a group of pattern matching with semicolon and period. But with Elixir you can't tell it's just def and end. Erlang's: -module(recursive). -export([fac/1]). fac(N) when N == 0 -> 1; fac(N) when N > 0 -> N * fac(N-1). You can tell fac(N) both are in a group of patter…

I honestly don't understand how this messes anything up... the elixir syntax produces something semantically equivalent with a lot less garbage. Opinions may differ I guess, but I find your Elixir example much easier to read than your Erlang example (I program in Elixir, so that's not much of a datapoint).

   fac(0) -> 1;
   fac(N) -> N * fac(N-1).

Post by devishard » Wed, Jan 25, 2017, 3:13 PM UTC

BeetleB wrote: post #109

aeturnum wrote: post #107

Earlier quoted context omitted.

I'm not devishard, but I parsed his statement slightly differently. He's not saying that Erlang makes things parallel magically. Rather, he's saying that Erlang forces tasks that /could/ be parallel to be parallel by default. Thus, Erlang will tend to maximize the sections of your program that are run in parallel compared to other languages.

Which would make the original commenter's point valid: >Your Erlang program should just run N times faster on an N core processor No, it won't. It will only be true for tasks that /could/ be (completely/embarrasingly) parallel (as you say). Which is kind of circular.