[ruby-core:114982] Re: [Ruby master Feature#19884] Make Safe Navigation Operator work on classes

How may `defined!?` be different from `Object#const_get` which is able to
lookup and load a constant given its name?

On Sun 8 Oct 2023 at 11:41, p8 (Petrik de Heus) via ruby-core <
[e-mail]> wrote:

> Issue #19884 has been updated by p8 (Petrik de Heus).
>
>
> nobu (Nobuyoshi Nakada) wrote in #note-10:
> > Rather the extension of `defined?` operator which returns the value
> (instead of the expression type string) or nil.
> >
> > Let's call it `defined=E2=81=89=EF=B8=8F` for now.
> > Isn't this what you want?
> >
> > ```ruby
> > defined=E2=81=89=EF=B8=8F(OptionalDependency)&.some_method
> > ```
>
> Yes, that would be nice.
>
> ----------------------------------------
> Feature #19884: Make Safe Navigation Operator work on classes
> https://bugs.ruby-lang.org/issues/19884#change-104853
>
> * Author: p8 (Petrik de Heus)
> * Status: Open
> * Priority: Normal
> ----------------------------------------
> If a constant isn't defined it will raise a NameError:
>
> ```ruby
> DoesNotExist.some_method # raises: uninitialized constant DoesNotExist
> (NameError)
> ```
>
> In libraries that have optional dependencies, we can check if the constan=
t
> is defined before calling a method on it:
>
> ```ruby
> defined?(OptionalDependency) && OptionalDependency.some_method
>
> ```
>
> Currently in Ruby, the Safe Navigation Operator is used to avoid
> NoMethodError exceptions when calling methods on objects that may be nil.
> It would be nice if we could use the Safe Navigation Operator to avoid
> NameError on undefined constants as well.
>
> ```ruby
> ClassThatMightNotExist&.some_method
>
> ```
>
>
>
> --
> https://bugs.ruby-lang.org/
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