From: matz@...
Date: 2016-05-22T12:34:17+00:00
Subject: [ruby-core:75677] [Ruby trunk Bug#12412][Rejected] Extend safe	navigation operator

Issue #12412 has been updated by Yukihiro Matsumoto.

Status changed from Open to Rejected

Although I don't say your idea is totally bad, it's not good to add it to Ruby for several reasons:

* it's not compatible
* introducing a new global variable is a terrible idea for any reason
* it would be slower by using respond_to? in run time
* it will hinder future type inference which is supposed to be introduced in Ruby3

Matz.

----------------------------------------
Bug #12412: Extend safe navigation operator
https://bugs.ruby-lang.org/issues/12412#change-58809

* Author: Daniel Ferreira
* Status: Rejected
* Priority: Normal
* Assignee: 
* ruby -v: 
* Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN
----------------------------------------
I wonder if we couldn't extend the safe navigation operator to work with any object rather than just nil.

I tend to still use this kind of code in some scenarios, specially when I work with objects with dynamic interfaces or arguments with different possible object types:

~~~ ruby
class Foo
   def bar(baz)
       if baz.respond_to?(:qux)
          return baz.qux
       end
       'whatever'
   end
end
~~~

What if we extend the safe navigation operator to work with any kind of object?
If it doesn't respond to the method it would return nil like this:

~~~ ruby
class Foo
  def bar(baz)
    baz&.qux || 'whatever'
  end
end
~~~

In order to not break backwards compatibility we should keep the current behaviour as well so the rational would be:

~~~ ruby
nil&.any_method
# => nil

foo&.non_responding_method
# => nil
~~~




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