From: shevegen@...
Date: 2018-11-07T00:33:44+00:00
Subject: [ruby-core:89739] [Ruby trunk Feature#15286] Proposal: Add	Kernel.#expand(*args)

Issue #15286 has been updated by shevegen (Robert A. Heiler).


I think one possible question in regards to the suggestion here is whether the above method may be useful
on its own, even without a shorthand syntax for Hash. (This is really just a question; I personally am
not really having any strong pro/con opinion.)

I also understand that using a method is different compared to the other two proposals. For example,

    { a }
    { a: a}

and

    {x, y}
    {x: x, y: y}

is different to:

    meth = 42
    p expand(:meth) # => {:meth=>42}

So using a method is different to the other two proposals (in the two older
issue request, by Ignatius and Shugo Maeda). Perhaps one or more use cases
could be described for a new method to be useful even without the hash
shorthand notation? I can not think of a good one right now but perhaps others
have some ideas. 

----------------------------------------
Feature #15286: Proposal: Add Kernel.#expand(*args)
https://bugs.ruby-lang.org/issues/15286#change-74782

* Author: osyo (manga osyo)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
This is a suggestion for Hash shorthand.
* [add support for hash shorthand](https://bugs.ruby-lang.org/issues/15236)

`Kernel.#expand(*args)` is expand `local variable` and `method` to Hash.
`*args` is method or local variable names.

## Example

```ruby
def meth
  "meth"
end
a, b, c = 1, 2, 3

# #expand args is local variable or method names
# Expand to { a: a, b: b: meth: meth }
p expand(:a, :b, :meth)
# => {:a=>1, :b=>2, :meth=>"meth"}

# Error: `expand': undefined method `hoge' for main:Object (NoMethodError)
p expand(:hoge)
```

What can be expanded,

* local variable
* method

and, If there are duplicate names, prioritize local variable.

```ruby
def meth
   "meth"
end
meth = 42

p expand(:meth)
# => {:meth=>42}
```

pull request: https://github.com/ruby/ruby/pull/2006




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