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Ruby 3.0 Preview 1

622 points| polysaturate | 5 years ago |ruby-lang.org

203 comments

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_odey|5 years ago

My thoughts:

- RBS: meh... might get more useful in the future (in 2-5 years maybe).

- Ractor: Wohooo! I'm writing a DAG library where I was thinking of implementing something like this, good to know I can use it and get real parallelism on top.

- Scheduler: :shrug: don't know about this one, might be relevant with future concurrent ruby code, any ideas?

- Rightward assignment: it's a bit awkward but I see the use case, just wish we had the pipe operator too like in Elixir.

- Endless method: this one is cute, I love it!

- Find pattern: oh boy, code reviews are going to be interesting now!

- Hash#except: yes, definitely a welcome one.

- Memory view: if this helps with numpy style gems it will be great!

- `send(:"do_#{ meth }", ...)`: don't do meth kids! (it's a joke!)... seems like a reasonable feature.

- `order of backtrace had been reversed`: good! it was confusing...

- Promote default gems to bundled gems (rexml): I like this one, if only nokogiri was a stdlib gem or part of core, imagine how much time would be saved instead of having to compile it every time in a `bundle install`.

- `Promote stdlib to default gems`: what does this mean? Do I now have to add `gem "securerandom"` to Gemfiles instead of having it by default and just needing to require it?

- Mjit improvements: can't wait to try it!

Overall, I'm delighted!

JohnBooty|5 years ago

My thoughts:

- A Ruby "Preview 1" release? Oh crap, I have to start Christmas shopping soon.

transfire|5 years ago

> Endless method: this one is cute, I love it!

Now they just need to make it defless too.

UncleOxidant|5 years ago

> - Endless method: this one is cute, I love it!

It's a weird name for it. It should probably be called something like 'equational method definitions'

reader_mode|5 years ago

>Rightward assignment statement is added. >fib(10) => x

This is exactly the kind of stuff I hated when I had to work with ruby in my last gig and why I will never accept a job using it again - soo many pointless and inconsistent ways to do the same thing ... they have method aliases for collection operations like map/filter in standard library ! .NET went with non-standard SQL-like names (select/where) and I'm not a fan but at least they made their choice and stuck with it. And it's inconsistent all over the place - like '!' postfix means "operation mutates the object" in std lib BUT in rails it means the operation will raise an exception and not return an error code.

Now they add a pointless operator that means completely different thing in other languages to throw off even more people.

It's just a hell of a language to maintain someone else's code in.

JohnBooty|5 years ago

I love Ruby, but I agree with you about disliking that kind of thing.

I've done Ruby since 2014 or so at a few shops. My general anecdotal experience:

- Lone Ruby coders often use a lot of that cutesy/obscure/dense stuff.

- Teams of people writing Ruby, with healthy code review practices, tend to value simple, easy-to-read Ruby.

- A lot of Popular Ruby gems (and projects at aforementioned Ruby shops) have Rubocop-based style guides. Rubocop has some very strict ideas about Ruby coding style. The defaults are mostly quite sane and it's easy to disable/customize the ones you disagree with.

Not making excuses for some of the more florid parts of Ruby's syntax and stdlib, but in practice I do find things are manageable!

d3nj4l|5 years ago

But that's what I love about Ruby! There's so many great ways to express logic, making Ruby a language that really rewards exploration. Of course, when working with a team on a production application, you'd set up standards everyone can agree on and understand with rubocop or prettier-rb (which I loathe and will not touch with a 10-foot long pole for my personal projects). That's also great for onboarding newcomers - they can get their feet wet with "standard" ruby at work, and then experiment with it more deeply in their own time, finding themselves in the ways they choose to express their logic. And then, every now and then if you find something really elegant and beautiful in your own exploration, you can introduce it to your team and add it to your team's style if they all agree on it. Between a language that makes all the choices for you, and a language that gives you the freedom to choose how you do things, I'd pick the latter nine times out of ten: at least in the latter, you can restrict yourself from the more wild stuff, but in the former you're forced into a narrow band of choices. I sure didn't ask for right assign, but I'll be trying it out in my personal projects!

strken|5 years ago

The thing that most annoyed me about Rails (not Ruby) was that

    users.size
    users.length
    users.count
are all valid, all useful, all have different meanings, are all present in plain Ruby but with different meanings, and contain absolutely no information about what they do.

For reference, .length loads everything and gets the length of the collection, .count runs a SQL COUNT query, and .size uses length if the query has already been run and .count if it hasn't.

gorgoiler|5 years ago

I would never share a Ruby code base with anyone either. It’s like issuing kindergartners a can of silly string and asking them to be sensible with it.

I consider myself a sensible developer, but even I’ve had some childish moments with Ruby: doing something I thought was clever and productive but which really just made my code inscrutable and unmaintainable...

...by other people. The flip side is I can just about figure out what I was trying to do when I read my own code: enough so that I still always use Ruby for personal projects.

Ruby is just too much fun and critically, to date, it’s the only language where I can write a page of code at the same speed I am thinking. It also usually executes first time without any errors, which is a joyous thing.

I am not claiming to be some kind of 10x uber hacker. Ruby just happens to be an incredibly wonderful language for thinking aloud with code.

philwelch|5 years ago

Ruby can also be an extremely decision-fatiguing language to write code in.

steveklabnik|5 years ago

! means “dangerous”, not mutation. Yes, that’s how it plays out because it is one kind of danger, but it’s not inconsistent.

jrumbut|5 years ago

I love all that stuff in Ruby to-date (used in it's appropriate place, following convention, etc) but the rightward assignment feels useless to me.

I have no idea why the few languages that allow it do so. I've never wanted it and I can't imagine it makes parsing simpler in a language where you are sometimes compiling code at runtime and where parsing is already pretty wild.

I've said this before and been wrong so let's hope this turns out to have excellent use cases.

levi0214|5 years ago

Totally agree.Different approaches to the same thing won't add points to the language.

P.S. the 'endless method definition' is meaningless, too.

> def square(x) = x * x

The original reason of this proposal was:

> Ruby syntax is full of “end”s. I’m paranoid that the ends end Ruby. I hope Ruby is endless. --mame (Yusuke Endoh)

It sounds like "let's add a new syntax for lisp because it has too many brackets"

wrp|5 years ago

Ruby has been referred to as Smalltalk meets Perl, and the problem of dealing with other people's code is one of the main things that kept me in the past from using Perl on text processing projects. The problem of collaborating in Perl was lessened a lot by adhering to Damian Conway's Perl Best Practices. Is there anything similar for Ruby?

cageface|5 years ago

In a sense Ruby is sort of a cleaned up Perl but maybe not cleaned up enough.

I fell totally in love with it almost 20 years ago but these days I think we have better languages to choose from even if their ecosystems aren't always as rich.

chrisoverzero|5 years ago

>.NET went with non-standard SQL-like names (select/where) […]

Which names do you believe are standard?

crehn|5 years ago

Happy someone else echoes my sentiment too, especially when Ruby seems to be beloved by everyone around. So many ways of doing the same thing; unnecessary cognitive burden for both reading and writing.

eddietejeda|5 years ago

If you interested in seeing how the 3x3 initiative* has come along, here are the benchmarks so far: https://github.com/mame/optcarrot#readme

Personally, I am very excited for this release.

* Matz's goal to get Ruby 3 to be 3x faster than Ruby 2.

--

@sosodev Thanks for the updated info!

czbond|5 years ago

I have been out of the ecosystem for a while, but use Ruby frequently. So the 3x3 is coming along? More up to date places I could see benchmarks or similar?

Note: I have been using Roda with Ruby 2 and it is pretty fast. Can't wait to see what it would be with 3x3.

thatguyagain|5 years ago

This might be a bit of a novice question, but will this affect the initializations of ActiveRecord objects in Rails anything?

For example, processing a large CSV file and inserting new rows in a database from it has always been extremely slow using Ruby/Rails unless you basically just write raw SQL that copies from the CSV and don't do any initializations of Rails models, #create, etc. I wonder if this will improve these things at all, but my guess is that it has to do with memory usage and not the speed of Ruby?

rco8786|5 years ago

This is all great stuff. I’m rather meh on RBS, mainly because separating types from code is less than ideal but I like the potential here.

But the right hand assignment operator. What on earth. Nobody asked for that and nobody wants it. Why.

inopinatus|5 years ago

Ruby already had a sort of limited form of rightward assignment, in exception rescue:

    begin
      #... do something
    rescue StandardError => ex
      #... handle exception
    end
The ex here can be any assignment expression, it's not just a lexical variable. So you could already do this:

    class Guru
      def meditate=(exception)
        puts "caught #{exception.inspect}"
      end
    end

    # later ...
    rescue OutOfCheeseError => Guru.new.meditate
i.e. creating a nice opportunity for passing error handlers around as an argument; or, this worrying idea:

    rescue TransactionError => Thread.current[:exception]
and now I'm afraid you can do this:

    Cat = Struct.new(:name) do
      class << self
        def all() = @all ||= Set.new
        def adopt=(...)
          all << new(...)
        end
      end
    end

    "Astrid" => Cat.adopt

djur|5 years ago

What's strange is that it seems to have been an offshoot of the pipeline operator (|>) work from last year[1], which was originally proposed as having an assignment syntax like

  foo |> bar(20) |> (x)
where x is assigned to. People didn't like that syntax, and there were issues with = being higher precedence than |> [2]. This new right-assignment operator was created in response to that [3].

The weird thing is that the pipeline operator got killed, so the original reason for r-assign no longer exists. It looks to me like there's just some people on the Ruby team who took a shine to it.

[1]: https://bugs.ruby-lang.org/issues/15799 [2]: https://bugs.ruby-lang.org/issues/15799#note-22 [3]: https://bugs.ruby-lang.org/issues/15921

burlesona|5 years ago

The examples given were all things that would be nice to do in the REPL. What I don’t understand is why not just define it in the repl, then, like ‘_’.

phaedryx|5 years ago

I have mixed feelings.

I'm not a fan of rightward assignment because I don't see much value and now the => operator has even more meanings.

I'm not a fan of endless methods because how lazy do you have to be to not want to type 'end'? My editor does it for me automatically. Now there is even more parsing.

dmix|5 years ago

JS has already adopted the endless style and it’s obvious when to use it and where a single line adds needless complexity. It’s really an overrated barrier to entry with a high return value in code simplicity (particularly aesthetically, which goes a long way with Ruby).

I have no comment on the rightward bit though. That is more... radical. Until I see how it is adopted generally.

levi0214|5 years ago

Completely unnecessary syntax.

It does nothing but add complexity.

shadykiller|5 years ago

I love Ruby and great to see Ruby love on hacker news. Just curious on how popular it is in the hacker news community ?

swat535|5 years ago

You know I've long stopped caring about how popular a language is in the community.

As I get older the question I ask myself is do I honestly enjoy using it? If the answer is yes, then I put it in my programming toolbox and ignore the hype.

koffiezet|5 years ago

I only ever tried out a rails tutorial once, and coming from a C/C++ background, but having used with many languages, too many things felt like magic back then, but no further experience with the language itself, so can’t really judge it.

However, now I’m on the operational side of things, and there are 2 types of applications I avoid to deploy/maintain, mainly because of their runtime: Java and Ruby apps. It’s very likely the Ruby runtime has improved, but we actually set up a haproxy with multiple instances of the same ruby app, which we just restarted every 2 hours, just to keep it running properly. Upgrading ruby back-then was a mess, and could break a lot of things. I can’t comment on the language itself, but the runtime left a very bad impression. I since then (4/5 years ago or so) have successfully avoided ruby, so it’s possible things have improved, but first impressions last...

Justsignedup|5 years ago

Reactor model. Nice. Very nice. So real ruby multithreading at last.

Okay time to upgrade to latest rails and wait for the multithreaded rails release. :P

sosodev|5 years ago

I suspect it will be quite a while before we see Ractor being used in Rails. Ractor is very strict about data isolation to prevent race conditions and existing code will need significant refactoring.

joelbluminator|5 years ago

I don't understand what you mean by "real multithreading". What I understand from Ractor is that it makes it safer to write concurrent code (e.g there are constructs that keep you from mutating shared data). But there is still a global VM lock, or is that gone in Ractor?

dorianmariefr|5 years ago

puma, the default webserver when using rails, is most-likely what would be using ractors

jasonhansel|5 years ago

Question: will the nonblocking scheduler start to make Ruby concurrency competitive with e.g. Node.js and Go? Currently Ruby mostly uses heavyweight threading mechanisms that cause trouble for I/O-bound microservices.

sosodev|5 years ago

In theory the scheduler should be similar to NodeJS and Ractor should be similar to Go if they’re both applied correctly.

andoriyu|5 years ago

Well, ruby was able to be concurrent for a while now. It has lightweight cooperative threads, it has reactor loops. The problem was/is/will be - lack of gems that support either of them.

EventMachine was a nightmare to work on and to work with, but with fibers it and some wrappers you could write some neat code. Most library were making a lot of bad assumptions - "there is a GIL and i'm running on a full thread and also wtf are threads in general, never heard of it?"

Almost no one in ruby world thought about writing a better code to make application faster, it was always about either finding a better gem or adding more application servers. Here is the closest ruby has been towards concurrency https://github.com/igrigorik/em-synchrony guess why it never took off.

Ruby 3.0 is a first step towards having libraries being aware that they are in on fiber and not thread.

maxpert|5 years ago

In theory yes; but if there is something native that uses blocking API then your thread will be still blocked.

gorgoiler|5 years ago

It feels like RBS is for library writers, so that they can ship type information to help the consumers of their library. It’s not really aimed at the consumers themselves — the long tail of casual Ruby hackers like me.

If RBS was for end users, adding types inline with the source code would make more sense compared to the RBS approach: keeping the source file and typedef file in sync.

That might actually be a pretty smart move. At first it seemed inconvenient to have to maintain a separate file for the type information, but maybe this focus on type-checking being made easy for the 90% of us who hack scripts is a much smarter one.

schneems|5 years ago

I don’t think anyone expects you to maintain two files. The idea is that RBS is an interface that is tooling agnostic. The idea is to have tooling (sorbet, etc.) generate those files for you.

crb002|5 years ago

I wish I had kept maintaining my port of Ruby to the IBM BLue Gene/L, "Blue Ruby". It scaled to millions of cores with MPI. Had distributed versions of familiar Ruby data types. There was no fork() - restriction of the BGL kernel not supporting it - only green threads - making parallel operations truly parallel with independent Ruby VMs and passing code to data instead of data to code.

Jarred|5 years ago

Does message passing mean it copies objects you send between threads / fibers, rather than sharing memory?

JavaScript has a similar pattern with Workers, and it makes concurrency for hot code impractical. Serializing/deserializing objects is a lot slower than just not doing that. In JavaScript’s case, you can also use SharedArrayBuffer, but Safari hasn’t re-enabled it.

kevincox|5 years ago

IIUC Yes. Although there are some cases where it can share immutable objects or pass ownership.

However you can always just open a shared memory region and write bytes back and forth. You don't get ruby types but if you are worried about performance that probably isn't much of a concern.

desireco42|5 years ago

There were times where I would not be able to sleep when such a release was done :). It isn't as much lately, but still, fantastic work by fantastic team. Congratulations!

There are some seriously good stuff there.

sickcodebruh|5 years ago

Didn’t see it linked in the preview announcement, here’s the RBS syntax guide: https://github.com/ruby/rbs/blob/master/docs/syntax.md

Glanced at it from my phone but it looks good! I’m looking forward to seeing it in RubyMine. Still sad that we can’t write these in .rb files but I wonder if the plan is to go the other way, eventually permit typed code in .rbs?

Does anyone know what the story will be with third-party definitions? Are we headed towards a DefinitelyTyped style repository for Ruby?

sosodev|5 years ago

It seems like the intent is for RBS to be auto generated from other tooling. Sorbet for example lets you write inline type definitions and is planned to fully integrate with RBS.

The other good thing about RBS being in separate files is it can be integrated into a library without breaking compatibility with older Ruby versions.

aryik|5 years ago

Great stuff! Does anyone who’s been in the Ruby ecosystem longer than me have a prediction for when Rails will support Ruby 3?

bilekas|5 years ago

Am I alone in saying; for some damn reason, I don't like Ruby.. I appreciate what it can do, and indeed what it does.. I just feel like I slipped in between that moment to appreciate it more. I will go and spend some time to learn it more but out of a novelty aspect.. And that makes me feel bad.

Glyptodon|5 years ago

I find it more productive, intuitive, and painless than the major scripting languages (PHP, JS, Python...), but it's definitely a bit different and less popular (given Python and JS are insanely popular).

joelbluminator|5 years ago

No you're not alone, it's (surprisingly, to me) one of the more controversial languages. I love it. Lot's of people don't. These things are subjective, we don't all have the exact same brains and life experiences, us humans appreciate different things and that's fine.

aitchnyu|5 years ago

Not a Rubyist. Would Ractor allow one process to use up all CPUs while avoiding copying objects? Can I build shareable objects with immutable lists and maps right now?

sosodev|5 years ago

Yes, Ractor allows you to share fully immutable objects. So you can freeze an array or hash and share it as long as it doesn’t contain any references to mutable objects.

phplovesong|5 years ago

Look like a great release! Have not used Ruby in years, but i recon the Ractor and Scheduler brings some nice perf improvements.

sarfraaz|5 years ago

I don't know why am I writing this, but..

monadic2|5 years ago

Ruby is a really cool language but I'm dying for an update where features are removed.

choward|5 years ago

Then Ruby isn't your language. There are a million ways to do everything by design. It's so you can make your code look pretty (or as they like to say "expressive") for whatever you interpretation of that means. It's one of the things that made me stop using it for most things.

riffraff|5 years ago

$SAFE was removed in this one :)

Lordarminius|5 years ago

The language is just becoming needlessly (?) complex. I'll stick to writing my code in --version 2.7 for the foreseeable future

zelly|5 years ago

So now there are basically no dynamically typed languages left. There's Scheme, JavaScript, what else? All languages nowadays are converging to TypeScript/Rust. It's kind of sad.

theonemind|5 years ago

Static typing seems like the underdog outside of Java EE/big enterprise stuff.

A matter of perspective, I suppose. You seem to like dynamic typing so static typing seems ubiquitous and inescapable. I find dynamic typing completely infuriating over 100 lines or so, and dynamic typing seems inescapable.

Others have pointed out the big dynamically typed languages, so I won't rehash, but suffice it to say, there basically are some dynamically typed languages left.

smabie|5 years ago

Julia, Python, Racket, Ruby, Common Lisp, Erlang, Clojure, etc...

But in my opinion, dynamic typing is a terrible idea for production code.

volkk|5 years ago

what do you mean? you can certainly use vanilla javascript if you really want, same with ruby. its not like types are forced down your throat

loktarogar|5 years ago

RBS is optional.

stevula|5 years ago

Python is pretty popular

mattgreenrocks|5 years ago

I hear x86 is dynamically typed

schwartzworld|5 years ago

Is JavaScript dead? what the fuck is my browser running?

hexbinencoded|5 years ago

I left Ruby because the performance and security weren't improving and the community was slowly dying. I delved into Go before that got flooded with newbs, then looked at Crystal and Pony, before settling on Rust and Haskell for most things.

shawxe|5 years ago

I see comments like this often and I find them deeply confusing. To me, it seems like most of the different programming/scripting languages you've listed excel at completely different things. I would be curious to hear what type of work you're doing where all of these languages have been, in some form or another, appropriate.

nurettin|5 years ago

How do you choose all this? I haven't been able to make a single decision for what language to use at work for the past 15 years. I thought wouldn't touch C#, ruby, delphi, kotlin and python but it all happened because someone was paying.

joelbluminator|5 years ago

In 5 years I bet you'd "settle" into some other new shiny language with "better" everything. There'll be a more right tool for the job. Nothing wrong with that mentality, I just prefer to settle with my tool of choice and call it a career.

stevebmark|5 years ago

I really wish Ruby would grow up and deprecate method_missing

chrisseaton|5 years ago

> I really wish Ruby would grow up and deprecate method_missing

method_missing is a deliberate and principled part of a message-passing approach to object orientated programming that gives you powerful options for composition and delegation.

You can say you don't prefer this style of programming, but it's not well-informed to say it's down to immaturity or ignorance of alternatives on their part.

nurettin|5 years ago

Metaprogramming is an important part of ruby, so method_missing stays.

samgranieri|5 years ago

Why? method_missing is one of the fun features of the language

whitepoplar|5 years ago

What's wrong with it?

cutler|5 years ago

Much as I would love to believe Ruby 3.0 delivers some kind of speed bump my simple test of doing what Ruby supposedly does best - parsing a log file with a regex - shows Ruby 16% slower than the Python equivalent.

  Ruby
  puts IO.foreach('logs1.txt').grep /\b\w{15}\b/

  Python
  from re import compile

  with open('logs1.txt', 'r') as fh:
      regex = compile(r'\b\w{15}\b')
      for line in fh:
          if regex.search(line): print(line, end='')
On my MacBook Pro (2013) running Catalina Ruby averaged 1.49 secs and Python 1.27 secs. The file `logs1.txt` is a 20Mb Apache log file. Pre-compilation with:

   reg = Regex.compile /\b\w{15}\b/
   puts IO.foreach('logs1.txt').grep reg
... slowed Ruby down to 1.57 secs.

Using --jit didn't change Ruby's overall time but considering it adds 700ms to Ruby's startup time execution time was faster.

karmakaze|5 years ago

The programs aren't doing the same things. The Ruby one seems to buffer the matches into a huge string then print. Don't know how different it would be but better to compare apples.

TylerE|5 years ago

That's not really surprising since regex in most languages is PCRE and not really indicative of actual interpreter performance.

Ecco|5 years ago

But it’s a super easy to read one-liner in Ruby!