[ruby-core:105215] [Ruby master Feature#14579] Hash value omission

Issue #14579 has been updated by baweaver (Brandon Weaver).


knu (Akinori MUSHA) wrote in #note-18:
> We should allow it to call a (private) method if no variable with the name defined.  We use methods in RSpec or with attr_reader that look like variables, and programmers don't necessarily distinguish between methods from variables when writing a program.  I believe this syntax should take methods into account.

I would agree that (private) methods are very useful here, especially `attr_*` methods. There are a few cases I would wonder what they do:

* `@var:` - Would this work with instance/class/global/constant variables if they're valid symbols?
* `a = 1; {a:, b: 3}` - Does it support mixing omissions and regular values?
* `p a:, b: 3` - Does it work with implied hashes / keywords? (I think yes).

I agree that `{ "#{ str }": }` should not be allowed, as it presents potential for abuse and vulnerabilities.

I've [PR'd the second case on mixed values](https://github.com/ruby/ruby/pull/4829), but just considered the first with ivars and similar concepts. I'm not sure which way that should go.

----------------------------------------
Feature #14579: Hash value omission
https://bugs.ruby-lang.org/issues/14579#change-93622

* Author: shugo (Shugo Maeda)
* Status: Closed
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
How about to allow value omission in Hash literals:

```ruby
x = 1
y = 2
h = {x:, y:}
p h #=> {:x=>1, :y=>2}
```

And in keyword arguments:

```ruby
def login(username: ENV["USER"], password:)
  p(username:, password:)
end

login(password: "xxx") #=> {:username=>"shugo", :password=>"xxx"}
```


---Files--------------------------------
hash_value_omission.diff (619 Bytes)


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