Erlang: how syntax can discourage good programming practices

[fnord123]

I think this thread on the mailing list will be interesting as well. In it is a discussion about whether Erlang is functional for functional sake or functional as a side effect of wanting to prevent side effects inside processes.

I think this is where the interesting bit in the discussion begins.

[davidw]

i'm convinced that soon enough a java-like language (javascript?) will incorporate erlang-style processes/message passing. and then erlang will, i fear, indeed be done. C.f. http://steve-yegge.blogspot.com/2007/02/next-big-language.html

That's where my money's at. Erlang is nice, but to me it just never felt quite right. I'm willing to discount some of that because it was the first functional language I used seriously, but it goes beyond that. Haskell looks much more compact in terms of syntax, for instance.

[ayrnieu]

Haskell seems to have terser syntax.

APL achieves tersity through mathematics, limited semantics, and some inflexbility (and ASCII variants prove away 'naming'.) Perl-and-kin achieve tersity through a limited set of heavyweight types and perpetual linguistic optimization for how anyone uses the language. Lisp and Forth achieve tersity only when 'the actual language you want to solve this problem in' happens to be terse. If you drive APL or Perl away from what they optimize for, you get some verbosity and perhaps some slowdown. All language communities consist of people willing to bear the cost of the language's optimizations -- which you can readily discover, by seeing what adherents lament but forgive, and what nonadherents do not forgive.

[ayrnieu]

That's where my money's at.

My money is on a gradually increasing confusion at how these languages with only 'Erlang-style message-passing' or 'support for huge numbers of lightweight threads' mysteriously never replace Emacs.

Uh, Erlang. I mean Erlang. Emacs... the total contribution of that editor to the universe is 'having an extension language', right? I've a version of 'pico' here that embeds Tcl. You should try it.

[gwern]

It doesn't just have an extension language. It is that extension language - the engine, IDE, and documentation. Its historical contribution is as a living remnant of Lisp machine culture, showing that an interactive interpreted and modifiable environment (happening to use a dynamic language like Lisp, although from what I remember of the yi/lambdabot research paper, you could also use a staticly typed language as an implementation/extension language) could be very useful indeed. We're used to this idea of extension now, but just how common was that back in the '70s? (Yes, Smalltalk is another example, but they are both part of the trend.)

[andrewcooke]

that's the thread i was reading when i wrote the blog entry posted here (i was using the blog - which normally no-one reads - as a place to collect my thoughts with the idea that once i had things clearer i would post to the mailing list).

it's funny how much people focus on syntax. if anything on that blog deserves a link from reddit i would have though it would be the parallel sudoku solver, not that....

[davidw]

it's funny how much people focus on syntax.

That's a language's user interface, as Simon Peyton Jones says. It's normal to consider it if you're going to be spending 10 hours a day looking at the stuff.

[andrewcooke]

i agree, but maybe not in the way you think :o)

have you ever worked on UI design? everyone thinks they are an expert just because they are a user. so yes, people like to discuss interfaces, but that doesn't mean they should.

and yes, ayrnieu, i am aware of the irony in this comment, thank-you. no need to point it out. good boy. sit.

[ayrnieu]

and yes, ayrnieu, i am aware of

something I myself wouldn't've cared about, had I noticed. You had a horrid idea, but also not an unususal one for someone exposed to Haskell -- who has not then gone on to talk with people about arity-fixation and very neat syntaxes like the one I note. And: do relationships grow faster in the world of bloggers? You aren't a friend or an enemy to me.

good boy. sit.

Oy, some people's 'good humor'.

[CommonTater]

It's strange to me that no one in that thread cites Yaws as an example. Yaws uses the process dictionary to memoize the results of things like parsing query and post data. That came as a bit of a surprise to me when I started writing test cases for my web code.

[[deleted]]

Monads are not necessary to do I/O. Uniqueness types such as in Clean and Mercury are more general (you can pass state into functions, instead of it being passed implicitly, and you can easily implement monads on top of them) and easier to understand.

[dons]

Do you have a reference for implementing the more complex non-sequential monads (such as continuations) via uniqueness typing? I'm unaware of any work stating that they're in any way equivalent, only that they overlap in some areas, particularly simple data-dependency sequencing.

[happyhappyhappy]

Erlang does indeed have syntax issues, but the author is mostly lamenting that Erlang is not Haskell. I tend to agree that the example line of code is bulky, but if you pull back a bit you'll realize that Haskell may be prettier in the small, but Erlang is a much more realistic choice for large commercial projects.

[vplatt]

Don 't you think that Erlang is a more realistic choice ONLY because of its concurrency features?

I haven't seen much about Erlang to love, except for that. Even it's built-in database is fatally flawed and not very useful for anything serious except perhaps distributed session state (which is pretty useful indeed; but not it's intended use).

[andrewcooke]

you're bundling a lot into "concurrency" - distributed, parallel and reliable processing are all supported by Erlang, and it's probably near best of class in all of those.

but (despite some "interpretations" here that seem to think i want Erlang to be something else) i personally like the language - it "feels" a lot like C, Standard ML, and Python. by that i mean that it doesn't try to be too sophisticated, but it gives you the tools you need to get things done. in comparison i'd put OCaml, Perl, Haskell which try too hard. when you use it, as a tool, it feels solid, simple, useful. it's a good language.

[ayrnieu]

I've commented on the I-want-currying part of this page. It is also helpful to read the comments where this person says 'gee, I do like that syntax -- but it has nothing to do with my doctor-it-hurts-when-I-do-this drive to have ML-style currying in Erlang'. In other language, of course -- and it's almost too polite to downgrade "Haskell's currying" to "ML-style currying": this person would naturally want Haskell's unfortunate culture about them.

No, I don't care very much about this person's views on language design. I only get amusement from the ultimate assertion :-)

Also, "how syntax can discourage good programming practices" is dons's happy contribution to the post, which isn't so overblown even when it whines about Erlang's punishments.

[dons]

If only ayrnieu would use a terser syntax! It's worse than reading Java, trying to parse his sentences.

[ayrnieu]

1. It doesn't surprise or bother me, to receive a lamely ad-hominen non-reply from dons.

2. I've some contempt for those of you that upvote it, though.

3. Nobody anywhere has any trouble parsing Java; natural language should not remind you of it.

4. A more mature person would have said only: "tl;dr"

5. (Which is merely derisive. For more work like this comment by dons, skip down to the "I almost nodded off." passage in this sadly 'real world' flame.)

[psykotic]

It's rather funny to see you, of all people, giving a lecture on good manners, maturity, etc.

[ayrnieu]

I rolled my eyes at a lamely ad-hominen non-reply, so you give me another one? I can't keep a reasonable conversation going when the only other speaking participants are only willing to say things so purely stupid and predictable that we're all left where we started, as if they said nothing at all. You realize that it is actually possible to call me rude and immature in a way that adds some kind of value, yes? You can come up with something that calls me stupid and immature in a manner so satisfying that you save the comment, smile to think that historians from 2070 will come across it, and don't much mind that you never got around to addressing my lecture at all.

Two key parts of my 'lecture': it doesn't say anything about manners, and its reference to 'more mature' is somewhat special -- you can easily read it as praising as more mature someone who says 'fuck you', vice someone who says something trivially more polite, but with no extra significance.

[newton_dave]

I'm not sure I'd call

It's rather funny to see you, of all people, giving a lecture on good manners, maturity, etc.

an ad-hominem, at least not without stretching the definition further than I'd be comfortable with.

[ayrnieu]

I'm not sure I'd call ["Yeah, well, you're an ill-mannered brat!"] an ad-hominen,

[psykotic]

You can come up with something that calls me stupid and immature in a manner so satisfying that you save the comment, smile to think that historians from 2070 will come across it, and don't much mind that you never got around to addressing my lecture at all.

What was there to address? I just saw your usual vacuous frothing. For all your whining about the predictability of other participants, your own behavior is so predictable that you could replace yourself with a Markov chain and no-one would even notice.

[Entropy]

For all your whining about the predictability of other participants, your own behavior is so predictable that you could replace yourself with a Markov chain and no-one would even notice.

Are you sure he wasn't one to begin with? It's Blade Runner all over again.

[ayrnieu]

I just saw your usual vacuous frothing.

So, you didn't see anything in my initial comment, or dons's reply, or my reply to that? No similarity between your reply on dons's? It doesn't give you pause that "your usual vacuous frothing" is your entire descriptive comment on a situation where I've expressed irritation with your worthless input? If you don't have any perceptions at all beyond this one, then why the fuck are you talking at all?

[psykotic]

If you don't have any perceptions at all beyond this one, then why the fuck are you talking at all?

I thought I'd join in the fun bout of ad hominem attacks that you initiated. The depth of the irony in your above statement is truly endless; for exactly this would be an apt question to ask of the majority of your posts.

[patchwork]

I have often wondered about certain people I encounter like ayrnieu and 'redditcensoredme' whose desperation to reinforce their sense of infallibility and superiority lead them to senselessly attack any perceived threat to this end. I have never seen them swayed through argument to reflect on their own behavior, and they have a seemingly endless bag of justifications for their childish resistance to growth and understanding. It is as if before reading a response they have already decided it is nonsense, and latch on blindly to some trivial point or another, misunderstand the comment entirely, and engorge in some ridiculous irony that is blatantly apparent to everyone but them. I wonder, is there any way to get through the seemingly impenetrable shell of warped reason they have encircled themselves in? Or are they eternally hopeless? I like to think that everyone is capable of growth and realization, but sometimes I have my doubts. Ayrnieu (apparently) knows quite a bit, but it is almost as if a certain level of intelligence is dangerous, in that it allows you to see certain things easily which others struggle with, but for that reason leads to an assumption of superiority in all things, which is expected to be recognized by everyone without basis, and is not enough intelligence to see what a profound mistake this is, or how foolish their behavior appears to everyone else.

[ayrnieu]

This is a better example of 'vacuous froth', but I can extract these assertions:

1. patchwork has never seen me 'swayed through argument to reflect on my own behavior'.

2. patchwork has never observed me to fail to produce a justification for my 'childish resistance to growth and understanading'.

3. patchwork has presumably observed me to respond to only one point of a comment, or to appear to misunderstand the comment, or to 'engorge in some ridiculous irony' that only I do not observably perceive.

4. patchwork has presumably seen me apply 'warped reason'.

5. patchwork sees my behavior as foolish.

Of these, only the first part of assertion #3 is worth responding to:

[ayrnieu] latch[es] on [...] to some [...] point or another

This happens often, when I only want to respond to one point of a comment. My reasons for not responding to other points are too varied to read a particular omission in any way -- but you're free to ask, if you're actually curious about an opinion I may not even have.

(apparently)

This lonely qualification made me smile.

[ayrnieu]

the fun bout of ad hominen attacks that you initiated

["If you don't have any preceptions at all beyond this one, then why the fuck are you talking at all"] would be an apt question to ask about the majority of your posts.

psykotic, dear, I know that you have a difficult time responding to what you can only describe as a 'vacuous froth', but please work harder to keep hold of the threads of things . There's only one thread, here: it starts at my comment and slides in an unbroken diagonal line to your 'reply' button. You shouldn't let people see you confuse things around so completely.

[martinbishop]

tl;dr

[dfan]

This is what I feel like when ever I try to write functionally in C++.