Issue #13290 has been updated by Yukihiro Matsumoto.

Status changed from Open to Feedback

I don't see how mush useful this proposal is.  Please show us concrete use-case.

Matz.

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Feature #13290: A method to use a hash like in a case construction
https://bugs.ruby-lang.org/issues/13290#change-63532

* Author: Tsuyoshi Sawada
* Status: Feedback
* Priority: Normal
* Assignee: 
* Target version: 
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We often want to translate a hash into a case construction and back. For example, suppose we have a case construction like this:

```ruby
case key
when /foo/ then "FOO"
when /bar/ then "BAR"
else "DEFAULT"
end
```

Given that the keys are ordered within a hash since Ruby 1.9, the information used in the case construction above can be expressed as a hash `h`:

```ruby
h = {
  /foo/ => "FOO"
  /bar/ => "BAR"
  ...
}
h.default = "DEFAULT"
```

At the moment, there is no straightforward way to translate the hash `h` into the case construction as above. I would like to have a method on `Hash` that takes a key and works like a case construction (i.e., applies the `===` method) as below:

```ruby
h.fetch_as_in_case_construction("barbar") # => "BAR"
```

The name `fetch_as_in_case_construction` is terrible. Perhaps someone can suggest a better name.



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