Issue #15419 has been updated by shuber (Sean Huber).


> Eregon (Benoit Daloze) wrote:
> Yes, in such a case you need to use `ruby_version_is` guards as documented on https://github.com/ruby/spec/blob/master/CONTRIBUTING.md#guards,
> because the behavior of previous versions will not change (unless this is decided to be backported, but very unlikely for a new feature, and even then the backport would be done later so the guards would be needed at first).

Perfect thanks @Eregon, [pull request](https://github.com/ruby/ruby/pull/2050) updated!

> oleynikov (Alexander Oleynikov) wrote:
> And I'm not sure why we need to change just #tap and not other methods.
> There are some discussions going on about passing arguments whith Symbol#to_proc shorthand: #12115, #15301, etc. Personally I'd rather see one of these implemented. It would also fix this issue.

Thanks for the links to the other discussions @oleynikov, pretty interesting, I'll keep an eye on those as well!

For `Kernel#tap` specifically I think it still makes sense to allow it to accept arguments like `Kernel#send` since they basically behave the same aside from `tap` always returning `self`. Relying on the proposals to support `Symbol#to_proc` with arguments (which could take awhile until they're actually merged) looks a bit more abstract than it needs to be:

```ruby
array.tap(:delete, object)
# vs
array.tap(&:delete.(object)) # if that's the syntax they agree on
# vs
array.tap { |a| a.delete(object) } # currently supported
```

----------------------------------------
Feature #15419: Allow Kernel#tap to be invoked with arguments like Kernel#send
https://bugs.ruby-lang.org/issues/15419#change-75727

* Author: shuber (Sean Huber)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Tapping methods without any arguments already has nice shorthand via `Symbol#to_proc`:

```ruby
object.tap { |o| o.example }
# vs
object.tap(&:example)
```

Unfortunately once other arguments are involved we have to switch back to the longer form:

```ruby
array.merge(other).tap { |a| a.delete(object) }
```

[This patch introduces](https://github.com/ruby/ruby/pull/2050) a convenient and familiar shorthand for these cases which behaves similar to `Kernel#send`:

```ruby
array.merge(other).tap(:delete, object)
```

Calling tap without any arguments or block still raises `LocalJumpError`:

```ruby
3.tap #=> LocalJumpError: no block given
```

This also makes the existing shorthand even shorter:

```ruby
object.tap { |o| o.example }
# vs
object.tap(&:example)
# vs
object.tap(:example)
```

---

**Pull request**: https://github.com/ruby/ruby/pull/2050



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