From: treznick@...
Date: 2015-10-23T03:58:09+00:00
Subject: [ruby-core:71169] [Ruby trunk - Feature #11537] Introduce "Safe	navigation operator"

Issue #11537 has been updated by Tom Reznick.


Thanks for the thoughtful replies guys! That definitely helps clarify the `.?` operator
Matthew Kerwin wrote:
> On 23/10/2015 2:46 AM, <merch-redmine@jeremyevans.net> wrote:
>  >
>  > Issue #11537 has been updated by Jeremy Evans.
>  >
>  >
>  > Tom Reznick wrote:
>  > > Hi,
>  > >
>  > > I think we may have found some unexpected behavior with the `.?`
>  operator.
>  > >
>  > > If I call the following:
>  > >
>  > >     s = Struct.new(:x)
>  > >     o = s.new()
>  > >     o.x #=> nil
>  > >     o.x.nil? #=> true
>  > >     o.x.?nil? #=> nil
>  > >     o.x.kind_of?(NilClass) #=> true
>  > >     o.x.?kind_of?(NilClass) #=> nil
>  > >     o.x.methods.include?(:nil?) #=> true
>  > >
>  > >
>  > > While it's arguably a bit peculiar to try to check that `nil` is `nil`,
>  in a `nil`-safe way, `.?kind_of?(NilClass)` could reasonably return `true`.
>  >
>  > I think it's completely expected that `nil.?kind_of?(NilClass)` returns
>  `nil` and not `true`.  The whole point of `.?` is to return `nil` without
>  calling the method if the receiver is `nil`.  I'm not sure if `.?` is a
>  good idea syntax-wise, but if you are going to have it, it shouldn't have
>  special cases for specific methods.
>  >
>  
>  I agree, or put another way: if you're testing for nil in two ways, .? has
>  higher priority. That makes it a programmer issue, not a ruby one.



----------------------------------------
Feature #11537: Introduce "Safe navigation operator"
https://bugs.ruby-lang.org/issues/11537#change-54543

* Author: Hiroshi SHIBATA
* Status: Closed
* Priority: Normal
* Assignee: Yukihiro Matsumoto
----------------------------------------
I sometimes write following code with rails application:

```ruby
u = User.find(id)
if u && u.profile && u.profile.thumbnails && u.profiles.thumbnails.large
  ...
```

or

```ruby
# Use ActiveSupport
if u.try!(:profile).try!(:thumbnails).try!(:large)
 ...
```
I hope to write shortly above code. Groovy has above operator named "Safe navigation operator" with "`?.`" syntax.
Ruby can't use "`?.`" operator.

Can we use "`.?`" syntax. like this:

```ruby
u = User.find(id)
u.?profile.?thumbnails.?large
```

Matz. How do you think about this?




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