[ruby-core:68760] [Ruby trunk - Feature #11034] Nil Conditional

Issue #11034 has been updated by Grzegorz Bizon.


Hi Nobuyoshi, thanks for reply !

Yes, this Nil Conditional Operator has to introduce new syntax. That is why this cannot be achieved via gem. Currently - of course - double question mark *??* violates syntax (in some cases) or is treated as tenary operator. But this doesn't have to be *??*.

I also agree that my version of nil conditional is too permissive and shouldn't return nil if variable does not exist. This was just less difficult to implement ;)

I simply believe that Nil Conditional Operator would be useful for every rubyist. In my opinion it is worth talking over, considering.

I will try to find related issue.

Kind regards,
 Grzegorz

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Feature #11034: Nil Conditional
https://bugs.ruby-lang.org/issues/11034#change-52043

* Author: Grzegorz Bizon
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
Hi everyone !

Some time ago I was thinking about Nil Conditional Operator in Ruby (`??`). This would be particularly useful to avoid frequent checking for nil, and should behave and look like Null Conditional Operator introduced in C# 6.0.

I was thinking about something like this (assume `var` is nil or doesn't exist):

~~~ruby
var??.method1.method2(123, 345).method3 { |i| i == 1 }
=> nil
~~~

When `var` is nil or doesn't exist, code above should return nil or NilConditionalClass object instead of raising NoMethodError or NameError.
This can also work with methods (assume `var` exists):

~~~ruby
var.method1??.method2(a, b)
=> nil
~~~

When `var` exists and can receive `method1`, but `method1` returns nil - this shouldn return nil instead of raising  `NoMethodError: undefined method `method2' for nil:NilClass`

When `var` exists and is not nil, and can receive `method1`, and object returned by `method1` can receive `method2` this, of course should behave as expected (like version without `??` operator) and return value according to implementation of method2.

When `var` doesn't exist - this should raise NameError.


I tried to create gem for that (https://github.com/grzesiek/nil-conditional) but from now on, only native implementation seems reasonable.

What do you think about that feature ? Maybe it is already considered, but I couldn't find anything similar at Google/this issue tracker (in that case I'm sorry for duplicate).

Thanks in advance for feedback !

Kind regards,
 Grzegorz




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