Every programming language has some fundamental idea(s) that drives its design and evolution. For Haskell that’s functional purity and state-of-the-art static typing, for Erlang that’s distributed programming and fault tolerance, for Clojure that’s simplicity and stability. What all these examples have in common is that they are relatively easy to understand and map to design decisions in the languages. This, in turn, makes it possible to determine down the road whether a language sticks to its core values or deviates from them.

Ruby, however, is very different. It’s world famous for its unique creed - “optimizing for programming happiness”. But what does this really mean? How does one optimize for happiness?

Unfortunately I’ve never heard Matz speak about this, so I’ll offer you my perspective instead - happiness is simplicity, readability, consistency, expressiveness and flexibility. If I have to describe happiness via Ruby code I’d probably do it like this:

3.times do
  puts "Ruby Rocks!"

Having numbers that are just regular objects, instead of some special primitive type is very powerful. Having code structure that’s somewhat intuitive even to non-programmers is very powerful.

I remember how amazed I was, when I was starting out with Ruby, that everything was an object - even things like true, false and nil.1 I remember how impressed I was with the opportunities that came with metaprogramming and how skillfully it was employed at the core of the language. Ruby also brought to the table a reasonable blend of object-oriented and functional programming techniques, even if it never really tried to promote a functional programming style.

Ruby certainly didn’t feel perfect, but felt really good. It was way ahead of most of the competition. A fun blend of Java and Lisp. Practical, powerful, expressive and flexible. And fun!

In recent years, however, I’ve been progressively more and more concerned with the direction in which Ruby has been heading when it comes to language design (think Ruby’s syntax). Here’s a list of changes and additions that I certainly never needed (or wanted):

  • Ruby 1.9 hash literals
  • Refinements
  • %i literals
  • Rational/Complex literals (2/3r, 2+1i)
  • Endless ranges (1..)
  • Safe navigation operator (&.)

Not all of those were bad additions in my book, though. Just unnecessary. I felt really strongly only about the hash literals and the refinements, as they brought a fair amount of complexity with them. Creating a special hash syntax that could express only a subset (although quite large) of all possible hash literals felt very short-sighted to me. I know that syntax really took off, but I still don’t like it. I’m used to it, but I don’t like it. I won’t say anything about refinements - I think their almost non-existing adoption is the perfect case study of their usefulness.

The other changes on my list had small impact and fit well with the existing language design, so I didn’t really care about their addition much. Still, I was disappointed when the safe navigation operator as introduced, as it basically acknowledged that it’s fine to return nil.

For the sake of completeness, here are some changes that I really enjoyed:

  • Lambda literals (a.k.a. stabby lambdas)
  • The ability to use symbols as procs
  • Keyword parameters
  • Squiggly heredocs (<<~)
  • Frozen string literals pragma
  • Making UTF-8 the default source code encoding
  • Unifying Integer and Fixnum

What all of them have in common what they solve actual problems in an unobtrusive way. I know that this is all very subjective, of course, but somehow I felt that all them fit very well with the rest of Ruby. Judging by the feedback all of them received and the wide adoption they got, I assume many people enjoyed them as well. Then again - Ruby 1.9 hashes are widely adopted as well. :-) I hope you get my point. Now back to the my frustrations.

The tipping point for me, however, was just a couple of weeks ago when it was announced that Ruby 2.7 would feature the following syntax for named block parameters:

# now
[1, 2, 3].each { |i| puts i }
(1..10).map { |i| i * 3 }
(1..9).each_slice(3).map { |x, y, z| x + y + z }

# Ruby 2.7
[1, 2, 3].each { puts @1 }
(1..10).map { @1 * 3 }
(1..9).each_slice(3).map { @1 + @2 + @3 }

I don’t know about you, but I really don’t think that saving a couple of characters is worth introducing special syntax. Not to mention a syntax that reduces to some extent the readability of the code.

If you push this to the extreme, consider the following example:

h = Hash.new { |hash, key| hash[key] = "Go Fish: #{key}" }

# vs

h = Hash.new { @1[@2] = "Go Fish: #{@2}" }

This new syntax was embraced by some, but it also was heavily criticized by others (including yours truly). There’s even an ongoing “petition” to make Matz reconsider its addition (or at least its current form). I sincerely hope that by the time you’ve finished reading this article you’ll support it as well.

There are several things about this syntax I dislike:

  • As the new named variables look like instance variables this adds a bit of cognitive overhead (and might break the syntax-highlighting in certain editors, which had a special coloring for instance vars, based on their @ prefix).
  • It hides the number of parameters yielded to the block.
  • It promotes the use of cryptic names.

Sure, in simple cases the new syntax looks OK:

names.map { @1.upcase }
names.each { puts @1 }

But why force people to learn new syntax for something as simple as that. Especially given the existence of other shorthand notations?

# This will be simplified in Ruby 2.7

So, we’ve got a new syntax that’s not shorter than what we can currently do (in the most command case with one parameter), and is not really as expressive as the “classic” syntax.

I also find it amusing that Ruby 2.7 introduced another similar feature, that’s more in line with what have been promoted so far - namely the method reference operator (.:). Its main usecase covers one of the typical usecases for the numbered parameters:

[2, 4, 8, 16, 32].map { |n| Math.log2(n) }

[2, 4, 8, 16, 32].map { Math.log2(@1) }

[2, 4, 8, 16, 32].map(&Math.:log2)

By the way, while .: doesn’t really get any awards for code elegance, it least it’s aligned with another existing pattern in Ruby. Victor Shepelev echoes my sentiment almost precisely here.

Now back to numbered block parameters. I really want someone to explain to me how a language change like this one fits with “optimizing for happiness”. What is the problem we had to solve that required the inclusion of syntax that’s far from ideal (as acknowledged by Matz himself)? Why did suddenly a 7 year old ticket went into development?

And, of course, don’t forget the extra impact of every language change. Now tools like parser and RuboCop have to account for the new syntax. The Ruby Style Guide should advise when it’s appropriate to use this and when it’s not. RuboCop should automate those suggestions into cops. Code that uses the new feature won’t be backwards compatible. And then we’re stuck with it forever.2 So much hassle for something so trivial that literally solves nothing.3

If that’s what passes for “optimizing for happiness” these days I think we’ve got a serious problem.


This post is not intended as a rant. It’s intended to be a conversation starter. I want to make it crystal clear that I’m not one of those people who’d just argue against innovation just for the sake of arguing. I understand that this syntax has some limited application here and there, and I understand that there might be people who even find it appealing and highly desirable. But I’m also certain that this feature can be implemented better than it currently is.4

In my opinion half-baked micro-optimizations add nothing, but complexity in the long run, and should be avoided. I’m really worried that Ruby has been gradually losing its way and has strayed from its creed. I hope this post will be a wake up call for some of you and will gain the attention of the Ruby Core Team as well.

I’m not a believer in languages designed by a committee and I have faith in Matz making reasonable decisions at the end of the day. However, I’m also a big believer in sticking to your values, developing a language that’s consistent and elegant. Random additions here and there stick out like sore thumbs, and are a recipe for frustration and friction in the long run.

Matz has been talking a lot in recent years about the big initiatives on the horizon (a.k.a. Ruby 3.0) like duck typing, faster performance (Ruby 3x3), introducing a better concurrency API (Guilds), repackaging the standard library, and the tools surrounding Ruby. I haven’t heard much in the direction of evolving Ruby from a syntactic perspective, though, and I’m left wondering if there’s any strategy there at all, or we’re just figuring things as we go. Actually, I lied to you - once I listened to Matz discuss for quite a while why it’s a good idea to add then as an alias to yield_self and this worried me even more.

Ruby actually has real problems to solve, and it’d be really great if someone focused on those. To wrap it up, I’d like to go back to the very beginning - Ruby’s creed. Here’s how the language is described on Ruby’s official web site:

A dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.

– ruby-lang.org

I think everyone suggesting new Ruby functionality and everyone from Ruby’s Core Team should remind themselves of this occasionally. Simplicity and elegant syntax are not things that happens by themselves - they require a lot of hard work and consideration. Now let’s go back to optimizing for happiness once again!

P.S. I’d really love to hear what do you think about all of this. Do you like all the language changes made in Ruby in the 2.x series? What’s the meaning of “optimizing for happiness” for you? Where do you think Ruby really needs to evolve in terms of syntax?

Update (2019-04-03): I guess the timing of my article was pretty good, as today another controversial feature landed in Ruby - beginless ranges (..10).5 According to their description A beginless range “they might not be as useful as an endless range, but would be good for DSL purpose”. There’s also a bit of example code to go with this:

ary[..3]  # identical to ary[0..3]
where(sales: ..100)

The second example looks pretty weird to me (I can easily imagine a clearer DSL like where { sales < 100 }), but the array usage seems reasonable. Given the presence of endless ranges already, I don’t think this is a bad addition per se, but it’s definitely one with very limited potential usefulness. I’ll leave it for you to decide if beginless ranges fit Ruby’s creed.

I’ve noticed today that the post has stirred quite the conversation on HackerNews. I didn’t have the time to go over all comments, but I’ve noticed that relatively few people are discussing Ruby’s philosophy and its overarching language design, and way more people are just arguing about syntax or saying I’m just another raging lunatic, who’s venting out. While I find this to be a bit disappointing, I don’t find it surprising at all.

By the way, surprisingly a lot of people are arguing about the &. operator in the comments, so it probably makes sense to make my position on it a bit clearer. Long story short - it’s useful, but it’s also dangerous in non-obvious ways. I dislike it mostly because it can really obscure the intent of some code and it really begs you to violate the Law of Demeter. People would normally say that &. solves real problems and give you a simple example like:


Law of Demeter aside, it makes sense. Consider, however, a few more subtle examples:

# A quick recipe for leaking nil returns
def foo

# Can any one of those methods return nil or just the first one? Go figure!

# Does any of those methods return nil or someone just decided to play it safe
# and introduced a potential nil return value that we now have to handle?

# How did we allow file to potentially be nil to begin with?

Unfortunately most people would happily cut some corners today than think about the long term maintenance and evolution of the code they are working on. Here’s a nice post on the subject that resonates strongly with how I feel about the safe navigation operator.

  1. Which are singleton instances of TrueClass, FalseClass and NilClass respectively. 

  2. The flip-flop operator (..) has been dying a slow death for many years now. Backwards compatibility makes most syntax constructs practically eternal. 

  3. On the bright side - we get a new favourite bike-shedding topic. 

  4. I believe that a special global variable would probably be a better solution. At least it’s more in line with what Ruby has been doing in the past (e.g. regex matches and $1, $2, etc). 

  5. Naming is hard!