[ruby-core:119502] [Ruby master Feature#20793] Allow Multiple Arguments for the .is_a? Method

[ruby-core:119502] [Ruby master Feature#20793] Allow Multiple Arguments for the .is_a? Method

[artemb (Artem Borodkin) via ruby-core]

Issue #20793 has been reported by artemb (Artem Borodkin).

----------------------------------------
Feature #20793: Allow Multiple Arguments for the .is_a? Method
https://bugs.ruby-lang.org/issues/20793

* Author: artemb (Artem Borodkin)
* Status: Open
----------------------------------------
I propose allowing multiple arguments to be passed to the .is_a? Method imply "OR" semantics:


``` ruby
name.is_a? String, Symbol
```

Currently, we need to write the following to achieve the same functionality:

``` ruby
[String, Symbol].include?(name.class)
```






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[ruby-core:119503] [Ruby master Feature#20793] Allow Multiple Arguments for the .is_a? Method

[nobu (Nobuyoshi Nakada) via ruby-core]

Issue #20793 has been updated by nobu (Nobuyoshi Nakada).


Also `kind_of?` method?

----------------------------------------
Feature #20793: Allow Multiple Arguments for the .is_a? Method
https://bugs.ruby-lang.org/issues/20793#change-110118

* Author: artemb (Artem Borodkin)
* Status: Open
----------------------------------------
I propose allowing multiple arguments to be passed to the .is_a? Method imply "OR" semantics:


``` ruby
name.is_a? String, Symbol
```

Currently, we need to write the following to achieve the same functionality:

``` ruby
[String, Symbol].include?(name.class)
```






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[ruby-core:119504] [Ruby master Feature#20793] Allow Multiple Arguments for the .is_a? Method

[Eregon (Benoit Daloze) via ruby-core]

Issue #20793 has been updated by Eregon (Benoit Daloze).


I think pattern matching can/should be used here instead of making `is_a?` more complicated:
```
irb(main):001:0> name = :abc
=> :abc
irb(main):002:0> name in String | Symbol
=> true
irb(main):003:0> name = 42
=> 42
irb(main):004:0> name in String | Symbol
=> false
```

`is_a?` is deeply optimized so accepting multiple arguments would likely make it slower or complicate things significantly.

----------------------------------------
Feature #20793: Allow Multiple Arguments for the .is_a? Method
https://bugs.ruby-lang.org/issues/20793#change-110119

* Author: artemb (Artem Borodkin)
* Status: Open
----------------------------------------
I propose allowing multiple arguments to be passed to the .is_a? Method imply "OR" semantics:


``` ruby
name.is_a? String, Symbol
```

Currently, we need to write the following to achieve the same functionality:

``` ruby
[String, Symbol].include?(name.class)
```






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[ruby-core:119505] [Ruby master Feature#20793] Allow Multiple Arguments for the .is_a? Method

[artemb (Artem Borodkin) via ruby-core]

Issue #20793 has been updated by artemb (Artem Borodkin).


Eregon (Benoit Daloze) wrote in #note-2:
> I think pattern matching should be used here instead 
Very nice, thank you!

If kind_of? (and alias is_a?) has a strong implementation optimization, I agree that this is not so important enhancement.

----------------------------------------
Feature #20793: Allow Multiple Arguments for the .is_a? Method
https://bugs.ruby-lang.org/issues/20793#change-110120

* Author: artemb (Artem Borodkin)
* Status: Open
----------------------------------------
I propose allowing multiple arguments to be passed to the .is_a? Method imply "OR" semantics:


``` ruby
name.is_a? String, Symbol
```

Currently, we need to write the following to achieve the same functionality:

``` ruby
[String, Symbol].include?(name.class)
```






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[ruby-core:119794] [Ruby master Feature#20793] Allow Multiple Arguments for the .is_a? Method

[matz (Yukihiro Matsumoto) via ruby-core]

Issue #20793 has been updated by matz (Yukihiro Matsumoto).

Status changed from Open to Rejected

`is_a?(A, B)` can be read as `is_a?(A) || is_a?(B)` or `is_a?(A) && is_a?(B)`. This ambiguity might lead to less readability.

Matz.


----------------------------------------
Feature #20793: Allow Multiple Arguments for the .is_a? Method
https://bugs.ruby-lang.org/issues/20793#change-110479

* Author: artemb (Artem Borodkin)
* Status: Rejected
----------------------------------------
I propose allowing multiple arguments to be passed to the .is_a? Method imply "OR" semantics:


``` ruby
name.is_a? String, Symbol
```

Currently, we need to write the following to achieve the same functionality:

``` ruby
[String, Symbol].include?(name.class)
```






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