Issue #17938 has been updated by matz (Yukihiro Matsumoto).


Although it requires migration complexity and ugliness for the time being, I think it's OK. 
We may need to investigate the performance of method calls with optional keyword arguments since some methods (e.g. `respond_to?`) are called often.

Matz.


----------------------------------------
Feature #17938: Keyword alternative for boolean positional arguments
https://bugs.ruby-lang.org/issues/17938#change-92363

* Author: matheusrich (Matheus Richard)
* Status: Open
* Priority: Normal
----------------------------------------
Some Ruby methods accept optional boolean arguments. This kind of parameter is known to be confusing since you cannot tell just looking at the method call what the parameter mean. For example:

```ruby
object.respond_to?(:symbol, false) # what does `false` mean?
object.methods(true) # what does `true` mean?
```

Now compare that to

```ruby
object.respond_to?(:symbol, include_all: false)
object.methods(regular: true)
# or
object.methods(only_public: true)
# or
object.methods(include_all: false)
```

I know Matz doesn't like breaking changes, so maybe we could have both to not break current calls, but allow a nicer syntax in newer Ruby? I don't know the depths of the Ruby C implementation, so here's what I thought in plain Ruby:

```ruby
def respond_to?(symbol, include_all_positional=false, include_all: nil)
  include_all ||= include_all_positional

  # ...
end
```

I'm willing to tackle this, if approved.

---Files--------------------------------
Screenshot from 2021-06-06 11-37-44.png (5.63 KB)


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