I understand the concerns about adding syntax and about Elixir having its
own identity. I’m not arguing that Elixir should copy Ruby, or that Ruby’s
choices are automatically good for Elixir.
That said, it’s also true that a significant portion of Elixir users
historically come from the Ruby ecosystem. Elixir has often been described
(rightly or wrongly) as having a Ruby-like surface syntax with Erlang
semantics, and that has been part of its approachability for many people —
myself included.
In that context, the Ruby comparison isn’t about imitation, but
about shared expectations around readability and ergonomics. Ruby 3.1’s {a:,
b:} is not a novelty feature; it’s a conservative form of value omission
inside already-keyed syntax. The proposal here does the same thing: it
removes duplication from %{a: a} without introducing new semantics or
implicit behavior.
Importantly, this syntax is *purely optional*. Existing explicit forms
remain valid and idiomatic. I intentionally did *not* enforce it via the
formatter, precisely to avoid pushing it onto users who don’t want it or
don’t find it clearer.
>From a learning perspective, this doesn’t raise the floor: users already
must learn atom keys and keyword syntax. This only shortens an expression
they already understand, and only when the variable name already matches
the key.
I fully agree that clarity should trump cleverness. My argument is that %{a:,
b:} stays within Elixir’s existing visual and semantic rules, while
addressing a very common repetition pattern that many users encounter in
real codebases.
On 22 Dec 2025 at 20:41:36, Brandon Gillespie <[email protected]> wrote:
> I'm trying to avoid being too argumentative here, but leaning back on "its
> used in ruby so it can't be hard to learn" just doesn't correlate. That it
> is in ruby doesn't implicitly make it easy to learn. As I said: we don't
> have to repeat another language's mistakes 😂
>
> FWIW, I have never liked ruby. 😂 I don't code in it, despite trying a few
> times. I don't think of Elixir as still a derivative of Ruby, and I'd
> suggest decoupling that notion, TBH. We should focus on Elixir, as itself.
> not as a derivative of something else. And I think we should focus on
> expanding the dev pool /outside/ of ruby, not limiting within it.
>
> As I hire new devs and train them into things, they come knowing other
> popular languages like python and javascript. I generally don't target ruby
> devs. And they're as rare as Elixir devs, TBH.
>
> I hadn't considered a spread assignment (or whatever you want to call it)
> as it would apply to keywords. Me personally? I'd only ever use it with
> maps, so I'd be 100% fine if it was simply limited to maps. Keywords
> already have a lot of differences from maps anyway. On that assertion, I'm
> not sure what other objects there are to using it only with maps.
>
> Splat operator: Sure. It was just an off-the-cuff suggestion. Saying there
> could be something else. Fixation on something that's a broken syntax in
> any of the top3 languages just makes it harder and more eldritch, also
> raising the bar for new devs.
>
> All the arguments I've heard for the colon syntax center around "Ruby & a
> few others do it this way" (and IMHO because somebody else does it isn't
> ever a good reason), and "I want it, so is this a good enough concession?"
>
> If this type of feature is really needed, I'd suggest even a working group
> session of interested parties, and just wipe the slate clean. Star by
> clearly defining the core desire/need, then talk through all the various
> challenges, throw out 5~10 more options, discuss, etc. (I don't know if
> this is already a thing the community does, or not).
>
> But to me this isn't something that should be done via a PR and an email
> conversation with a few people who happened to be noticing things on the
> list during a holiday season.
>
> Just my "two cents" as it were, from one normally watching in the peanut
> gallery.
>
> -Brandon Gillespie
>
>
> On 12/22/25 10:07 AM, Allen Madsen wrote:
>
> Another language doing something certainly isn't a reason to adopt it.
> However, widespread usage of a feature in a language speaks to its
> usefulness and learnability. As stated previously, usage of this syntax is
> used pretty widely in the ruby community. So, I don't personally buy the
> "this is hard to learn" argument, because there's evidence to the contrary.
>
> It's also worth noting that Elixir would have the same reason as ruby to
> use the non-bare word syntax. In elixir you can do:
>
> def foo(bar, baz: baz) do
> end
>
> Where the keyword arguments are gathered into a keyword list. Barewords
> here wouldn't make sense by themselves even if you wrap them in a list.
>
> # not the same
> def foo(bar, baz) do
> end
>
> # is this matching [baz] or [baz: baz]
> def foo(bar, [baz]) do
> end
>
> The colon doesn't have that problem.
>
> def foo(bar, :baz) do
> end
>
> Towards the recommendation for using *, I think that is a less good option
> because it looks like the splat operator in ruby and the pointer operator
> in other languages.
>
> Allen Madsen
> http://www.allenmadsen.com
>
>
> On Mon, Dec 22, 2025 at 10:52 AM Brandon Gillespie <[email protected]>
> wrote:
>
>> Please do not do this WITH THIS SYNTAX (but I really do want
>> destructuring/etc).
>>
>> It looks like an error, no matter how hard you squint, nor rationalize.
>>
>> There is no reason to repeat Ruby's mistakes, nor other languages doing
>> the same. "because they are doing it" is not a reason.
>>
>> The other problem with this is it is optimizing for the /advanced/ user,
>> and not the common and new user. The community should be focused on making
>> it EASIER to get into elixir, not harder.
>>
>> New users coming from the biggest languages out there are what we should
>> consider, not those with less popular languages. And like it or not, the
>> popular languages are Java, Python, Javascript. None of them support the
>> proposed visually borked syntax.
>>
>> if anything, of those top three languages, Javascript does it with bare
>> variables—so the only argument with weight (imho) that "other languages do
>> it" would be for bare vars. But José has declined that syntax (I forget the
>> reasons).
>>
>> If the option for bare vars is off the table completely and forever,
>> perhaps consider another token?
>>
>> Asterisk almost could work. In spirit it almost hearkens back to C's
>> pointer. And in this case used as a unary operation it wouldn't collide
>> with multiplication, which is a binary operation.
>>
>> I don't love it, but fwiw:
>>
>> ```
>> asdf = "foo"
>> %{*asdf}
>> ```
>> => `%{asdf: "foo"}`
>>
>> ```
>> %{*foo, *bar} = %{foo: "narf", bar: "boop"}
>> IO.inspect({foo,bar})
>> ```
>>
>> => {"narf", "boop"}
>> But just in my own opinion, anything extending the core syntax should
>> always keep "new programmers" as a key metric for if it'll work well.
>>
>> -Brandon Gillespie
>>
>>
>> On 12/21/25 10:15 PM, Allen Madsen wrote:
>>
>> It'd be nice to support pinning as well.
>>
>> x = 1
>> %{^x:} = %{x: 2} #=> %{x: ^x} = %{x: 2}
>>
>> Allen Madsen
>> http://www.allenmadsen.com
>>
>>
>> On Sun, Dec 21, 2025 at 10:42 PM Данила Поярков <[email protected]>
>> wrote:
>>
>>> Yes, you can try that on my PR:
>>>
>>> bin/elixir -e '%{foo:, bar:} = %{foo: 1, bar: 2}; IO.inspect({foo, bar})'
>>>
>>>
>>> On 22 Dec 2025 at 04:15:02, Joseph Lozano <[email protected]> wrote:
>>>
>>>> Would this work for destructuring too?
>>>>
>>>> ```elixir
>>>> %{foo:, bar:} = my_map # assigns `foo` and `bar`
>>>> ```
>>>>
>>>> On Sun, Dec 21, 2025, at 17:07, Ryan Winchester wrote:
>>>>
>>>> I wish for this often.
>>>>
>>>> I would happily settle for this just to have it, although I don’t like
>>>> the syntax and also prefer the %{a, b} syntax like other languages (JS/TS,
>>>> Rust, ...)
>>>>
>>>> On Sunday, December 21, 2025 at 2:12:13 AM UTC-4 [email protected]
>>>> wrote:
>>>>
>>>> I'm in support of this 👌
>>>>
>>>> It's a reasonable trade off from other concerns and as someone who
>>>> works with people moving from other languages to Elixir often, they are
>>>> *constantly* looking for this syntax. Given that this exact syntax is used
>>>> in other languages also adds some regularity to it, despite my personal
>>>> preference for js style %{a, b}. The "accidentally being a tuple" issue
>>>> with that syntax goes away for 99% of cases conveniently with the type
>>>> system FWIW :)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Sun, Dec 21, 2025 at 10:58 AM, Danila Poyarkov <[email protected]>
>>>> wrote:
>>>>
>>>> Hi everyone,
>>>>
>>>> José Valim suggested I move the discussion here from my PR:
>>>> https://github.com/elixir-lang/elixir/pull/15023
>>>>
>>>> I've implemented shorthand syntax for atom-keyed maps and keywords:
>>>>
>>>> ```elixir
>>>> %{user:, conn:} # => %{user: user, conn: conn}
>>>> [foo:, bar:] # => [foo: foo, bar: bar]
>>>> f(name:, age:) # => f(name: name, age: age)
>>>> %{map | a:, b:} # => %{map | a: a, b: b}
>>>> ```
>>>>
>>>> I know this topic has been discussed many times before:
>>>>
>>>> - Proposal: Short Hand Property Names (2017):
>>>> https://groups.google.com/g/elixir-lang-core/c/XxnrGgZsyVc
>>>> - Consider supporting a map shorthand syntax (2018):
>>>> https://groups.google.com/g/elixir-lang-core/c/NoUo2gqQR3I
>>>> - ES6-ish property value shorthands for maps? (2016):
>>>> https://elixirforum.com/t/es6-ish-property-value-shorthands-for-maps/1524
>>>> - Has Map shorthand syntax caused you any problems? (2018):
>>>> https://elixirforum.com/t/has-map-shorthand-syntax-in-other-languages-caused-you-any-problems/15403
>>>>
>>>> Most of these discussed the ES6-style `%{a, b}` syntax, which José made
>>>> clear had "zero chance" of being accepted — mainly because `%{a, b}` vs
>>>> `{a, b}` differs by one character, making maps and tuples too easy to
>>>> confuse.
>>>>
>>>> The colon-based syntax `%{a:, b:}` is different. The `:` that signals
>>>> "this is a key-value pair" stays there. There's no visual confusion with
>>>> tuples because `{a:, b:}` is not valid Elixir syntax anyway.
>>>>
>>>> José mentioned in the PR that he actually prefers this approach over
>>>> bare variables, but it was "deemed not acceptable by most people" in a
>>>> previous discussion. I'd like to understand what the objections were.
>>>>
>>>> Reading through the old threads, I found these concerns:
>>>>
>>>> - "Removing explicitness for the sake of brevity doesn't appeal to me."
>>>> (Chris Keathley)
>>>> - "Shorthand syntax makes that coupling even less obvious" — if you
>>>> change a key, you need to find all functions that relied on that variable
>>>> name. (Chris Keathley)
>>>> - "This will just add complexity to the language to save a few
>>>> keystrokes for advanced users." (Matt Widmann)
>>>>
>>>> These discussions happened in 2016-2018. Since then, Ruby 3.1 shipped
>>>> this exact syntax in December 2021 — almost 4 years ago. The syntax is
>>>> `{x:, y:}` for hashes and `foo(x:, y:)` for keyword arguments, exactly what
>>>> I'm proposing for Elixir.
>>>>
>>>> The Ruby reception was mixed at first — Bozhidar Batsov (RuboCop
>>>> maintainer) was critical (
>>>> https://batsov.com/articles/2022/01/20/bad-ruby-hash-value-omission/)
>>>> but still allowed it in RuboCop defaults. Four years later, the syntax is
>>>> widely used.
>>>>
>>>> The same pattern (sometimes called "field punning") also exists in Rust
>>>> and OCaml.
>>>>
>>>> `%{user: user, conn: conn}` is already common in Elixir — this just
>>>> removes the repetition. The colon stays visible, so it's not as "magic" as
>>>> the bare variable approach. And Ruby has been using it for 4 years now
>>>> without issues.
>>>>
>>>> The implementation is ready and all tests pass. I'm curious whether
>>>> opinions have changed since 2018.
>>>>
>>>>
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