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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