From: non.dmitriy@...
Date: 2019-11-12T18:58:09+00:00
Subject: [ruby-core:95819] [Ruby master Feature#16341] Proposal: Set#to_proc

Issue #16341 has been updated by Nondv (Dmitry Non).


This *is* a syntactic sugar. Using `&` + `to_proc` in this case is the same (not technically, but algorithmically, I guess) as providing an explicit block `something.some_method { |x| some_set.include?(x) }`

I don't find it crucial in any way and, to be honest, I don't really use sets that much (I prefer using hashes directly). But this feature could make some more a tiny bit easier to read from English language perspective (I *think*)

----------------------------------------
Feature #16341: Proposal: Set#to_proc
https://bugs.ruby-lang.org/issues/16341#change-82646

* Author: Nondv (Dmitry Non)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
``` ruby
class Set
  def to_proc
    -> (x) { include?(x) } # or method(:include?).to_proc
  end
end
```

Usage:

```ruby
require 'set'

banned_numbers = Set[0, 5, 7, 9]
(1..10).reject(&banned_numbers) # ===> [1, 2, 3, 4, 6, 8, 10]
```



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