Node is popular because it allows normal people to do high concurrency servers. It's not the fastest or leanest or even very well put together - but it makes good trade offs in terms of cognitive overhead, simplicity of implementation, and performance.
I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programming model for app developers. I love Go so much (SO MUCH), but I cannot get past the fact that goroutines share memory or that it's statically typed. I love Erlang but I cannot get the past the syntax. I do not like the JVM because it takes too long to startup and has a bad history of XML files and IDE integration - which give me a bad vibe. Maybe you don't care about Erlang's syntax or static typing but this is probably because you're looking at it from the perspective of an engineer trying to find a good way to implement your website today. This is the source of our misunderstanding - I am not an app programmer arguing what the best platform to use for my website--I'm a systems person attempting to make programming better. Syntax and overall vibe are important to me. I want programming computers to be like coloring with crayons and playing with duplo blocks. If my job was keeping Twitter up, of course I'd using a robust technology like the JVM.
Node's problem is that some of its users want to use it for everything? So what? I have no interest in educating people to be well-rounded pragmatic server engineers, that's Tim O'Reilly's job (or maybe it's your job?). I just want to make computers suck less. Node has a large number of newbie programmers. I'm proud of that; I want to make things that lots of people use.
The future of server programming does not have parallel access to shared memory. I am not concerned about serialization overhead for message passing between threads because I do not think it's the bottleneck for real programs.
"I love Erlang but I cannot get the past the syntax."
I cannot understand this hangup about syntax. Syntax is the easiest thing to learn with a new language, you just look it up. It's the semantics and usage where the real problems are.
Erlang doesn't have static typing, it is dynamically typed. It has always been dynamically typed.
And however you look at it doing highly concurrent systems with processes is much easier. And who says that processes imply "parallel access to shared memory"? Quite the opposite actually.
syntax is the user interface of the language. it is one of the parts you have to deal with on a constant basis, both writing and reading code. i can well see how an unpleasant syntax can be a constant, grating annoyance when dealing with a language. (i happen to really like erlang's syntax, but it definitely has very different aesthetics from javascript's)
I think it would be dangerous if Erlang's syntax were to resemble that of another language like Java or C. Especially for beginners. That is because if things look the same you expect them to behave the same, and Erlang's semantics is very different from those languages whose syntax people think it should be like.
There is no getting around the difference in semantics. For this I think that having a different syntax is actually better. Also there are things in Erlang which are hard to fit syntactically into the syntax of OO languages, for example pattern-matching.
Honestly? Erlang's syntax is not that bad. It's not great in that it has prolog legacy with uncanny valleys to C-legacy left and right, but it's effective.
Really the only really tricky thing for a newbie is strings.
these things are very much a matter of taste. what does "effective" mean with respect to syntax? for instance, lispers will argue that their syntax is effective because of the things it lets you do, but that's orthogonal to whether it's actually a pleasant syntax to program in, which comes down to personal taste[1]. likewise, i love mlish syntax, but opa, a language steeped in ml semantics, nonetheless switched to something more javascripty for their main syntax because it proved more popular[2]. and read through the wrangling over ruby versus python sometime - the two languages are very similar under the hood, but their respective syntaxes are one of the things proponents of each language complain about when they have to use the other.
[1] as larry wall famously said, "lisp has all the visual appeal of oatmeal with fingernail clippings mixed in."
It takes a lot of chutzpah for Larry Wall to say anything critical about Lisp syntax. Larry Wall. Come on.
I'm not the author of the comment above, but I think Erlang's syntax is effective in that it strongly emphasizes computation by pattern matching. If you write very imperative code in it (as people tend to, coming from Ruby or what have you), yes, it will look gnarly. Good Erlang code looks qualitatively different. There are pretty good examples of hairy, imperative Erlang code being untangled in this blog post: http://gar1t.com/blog/2012/06/10/solving-embarrassingly-obvi...
The . , ; thing is a bit of a hack, admittedly -- I suspect that comes from using Prolog's read function to do parsing for the original versions of Erlang (which was a Prolog DSL), and reading every clause of a function definition at the same time. Prolog ends every top-level clause with a period, not "; ; ; ; .". (Not sure, but a strong hunch, supported by Erlang's history.) I got used to it pretty quickly, though.
As in Prolog ',' and ';' are separators: ',' behaves like an and, first do then and then do this (as in Prolog); while ';' is an or, do this clause or do this clause (again as in Prolog). '.' ends something, in this case a function definition. Erlang's functions clauses are not the same as Prolog's clauses which explains the difference.
It is very simple really, think of sentences in English and it all becomes trivially simple.How many sentences end in a ';'?. And you almost never need to explicitly specify blocks.
Sort of. The syntax evolved at the same time we were moving from Prolog onto our own implementation, which forced us to write our own parser and not rely on the original Prolog one. The biggest syntax change came around 1991, since then it has been mainly smaller additions and adjustments.
Anyways, my experience is that all languages will get people criticizing them. And, in my experience, those kinds of criticisms should almost always be categorized as "does not want to talk about language FOO" and a proper response is probably something like "if you don't want to give that subject the respect it deserves, let's change the subject to something you find interesting".
Erlang syntax maybe jarring but one benefit of it is there is actually very little syntax relative to languages like Java, C++, Python. There isn't that much to hold in your head. I can switch between Erlang and another language pretty effortlessly because the context switch is so small.
FWIW I believe "Maybe you don't care about Erlang's syntax or static typing" was referring to his earlier mention of Go as statically typed. A comma would have improved the clarity :-)
"I love Erlang but I cannot get the past the syntax."
I also thought this. For some reason though the more I use it the more I am coming around to its syntax. There are lots of gotchas when compared with other popular languages, but still its syntax has grown on me recently.
At the opposite end of the syntactic spectrum is Lisp. The more I use Clojure the more I am loving it as well.
"The future of server programming does not have parallel access to shared memory."
I agree. The future of server programming is also not spawning multiple child processes. The question I have is how far off is that future? I know that most of my web applications today simply run in multiple spawned OS processes.
I agree. The future of server programming is also not spawning multiple child processes. The question I have is how far off is that future? I know that most of my web applications today simply run in multiple spawned OS processes.
Barring a massive shift in hardware architectures, shared access by cooperating threads is your only option for high-performance shared state. Look at core counts vs core flops for the last five years. Look at Intel's push for NUMA architectures. This is a long-scale trend forced by fundamental physical constraints with present architectures, and I don't see it changing any time soon.
Anyone telling you shared state is irrelevant is just pushing the problem onto someone else: e.g., a database.
"The future of server programming does not have parallel access to shared memory."
What about STM in Clojure? It's technically parallel access to shared memory, but the transactional nature obviates the need for mutexes and all the crap that makes shared memory a pain in the ass.
Erlang has a far superior computational model an implementation than Node, it can handle way more requests faster and is newcomer friendlier as any web request is simply a message received.
I do not see how you can simultaneously care about making programming better but not care about how people use what you're making to solve that problem.
Programming is a verb describing what people do with programming systems, and we're nowhere near the point where it can be done automatically yet. You cannot remove people from the equation and claim to be interacting with it.
I think he's saying he wants to make programming better for newbies.
It really kinda sucks for them right now.
Serious hard-core engineers that need serious tools are actually pretty well served by current tools. No, no, they're not perfect. But we're way better off than somebody who's just beginning in terms of what tools are aimed at us.
Agreed, and as computing grows messaging will just get cheaper and cheaper. zeromq is a great example of that, 5 million messages per second over TCP on a macbook air is not half bad.
Personally I like static typing, especially if somewhat optional, it's something we effectively do through documentation anyway (via JSdoc or similar), but makes it concrete.
I dont think light-weight threads sharing memory is so bad, symmetric coroutines are more or less the same as an event loop IMO, the thought put into working with them is more or less identical, just without callback hell and odd error-handling, but I suppose going all-out with message passing could be fine. I think that's still a bit of an implementation detail unless you get rid of the concept of a process all together and start just having a sea of routines that talk to each other.
I think the reaction from many long-term programmers who have switched technologies, careers, frameworks, languages is to the "...use it for everything?" mantra. I applaud your goals and the success at getting more people to program and build things. That's what we really do need. Let's hope this audience is reading HN with an open mind and figure out, as many here have, that the problem to be solved is the most important decision, not the tool.
Is that good or bad? I personally don't mind Erlang syntax at all or the syntax overhead to you have to write a gen_server that does nothing. Elixir saves you some of that overhead. It's kind of like CoffeeScript for Erlang. It's fully compatible since it compiles to Erlang AST which compiles to BEAM. You can do "everything" with Elixir you can do with Erlang. Of course, you have to understand how to work with Erlang/OTP to actually benefit.
I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programming model for app developers. I love Go so much (SO MUCH), but I cannot get past the fact that goroutines share memory or that it's statically typed. I love Erlang but I cannot get the past the syntax. I do not like the JVM because it takes too long to startup and has a bad history of XML files and IDE integration - which give me a bad vibe. Maybe you don't care about Erlang's syntax or static typing but this is probably because you're looking at it from the perspective of an engineer trying to find a good way to implement your website today. This is the source of our misunderstanding - I am not an app programmer arguing what the best platform to use for my website--I'm a systems person attempting to make programming better. Syntax and overall vibe are important to me. I want programming computers to be like coloring with crayons and playing with duplo blocks. If my job was keeping Twitter up, of course I'd using a robust technology like the JVM.
Node's problem is that some of its users want to use it for everything? So what? I have no interest in educating people to be well-rounded pragmatic server engineers, that's Tim O'Reilly's job (or maybe it's your job?). I just want to make computers suck less. Node has a large number of newbie programmers. I'm proud of that; I want to make things that lots of people use.
The future of server programming does not have parallel access to shared memory. I am not concerned about serialization overhead for message passing between threads because I do not think it's the bottleneck for real programs.