[ruby-core:105028] [Ruby master Feature#18124] Hash shorthands (matching constructors functionality in JS)

Issue #18124 has been updated by myxoh (Nicolas Klein).


mame (Yusuke Endoh) wrote in #note-3:
> For "Destructuring", you can use one-line pattern matching since Ruby 3.0:
> 
> ```
> hash = {a: 'a', b: 'b'}
> hash => { a:, b: }
> p hash[:a] #=> "a"
> ```
> 
> For "Constructor", it is a long-running topic: #14579, #17292, and maybe other tickets I cannot remember. But as far as I recall, no one proposed this particular syntax `%C{ }`.

Thank you, haven't had enough of a chance to play with Ruby 3. Clearly I missed things.
I've updated to remove the reference to the destructuring. I've also made a slight update to make it more consistent with ruby's existing % literal constructors (as that's the intent here)

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Feature #18124: Hash shorthands (matching constructors functionality in JS)
https://bugs.ruby-lang.org/issues/18124#change-93436

* Author: myxoh (Nicolas Klein)
* Status: Open
* Priority: Normal
----------------------------------------
# **Suggestion:**
To implement one shorthand operators that allows you to construct hash into local variables and construct local variables into a hash.

# **Context:**
Javascript and other languages have a similar feature. It's helpful, and I don't think there's anything stopping Ruby for supporting it.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
Ruby also supports destructuring from an array.

# **Syntax:**
### Constructor:
The constructor shorthand would allow you to create a hash where the symbol key has the same name as the variable.

For example:

```ruby
local_number = 1 
user = OStruct.new(name: 'john')
hash = %C{ local_var user }
```

would be equivalent to:
```ruby
local_number = 1 
user =  OStruct.new(name: 'john')
hash = { local_number: local_number, user: user }
```

The new syntax is based on ruby's existing literal constructors syntax.






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