[ruby-core:110315] [Ruby master Feature#17290] Syntax sugar for boolean keyword argument

["sawa (Tsuyoshi Sawada)" <noreply@ruby-lang.org>]

Issue #17290 has been updated by sawa (Tsuyoshi Sawada).


I think Marc-Andre and Brandon's idea can be limited to be relevant only for receiving the parameters (in a definition), and it will still make sense. My proposal is is about the parameters (in a method call). I think they can be kept distinct.

I rarely see people using `gets(chomp: true)`, and I think it is because it is shorter to write `gets.chomp`.  It is a pity that such a useful feature was introduced, but no one uses it because the old school way is more convenient.

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Feature #17290: Syntax sugar for boolean keyword argument
https://bugs.ruby-lang.org/issues/17290#change-99605

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
----------------------------------------
We frequently use keyword arguments just to pass `true` value out of the truthy/falsy options given. And in many such cases, the falsy option is set as the default, and only the truthy value is ever passed explicitly. I propose to have a syntax sugar to omit the value of a keyword argument. When omitted, it should be interpreted with value `true`.

```ruby
gets(chomp:)
CSV.parse(" foo var ", strip:)
```

should be equivalent to

```ruby
gets(chomp: true)
CSV.parse(" foo var ", strip: true)
```

Additionally, we may also extend this to pragmas.

```ruby
# frozen_string_literal:
```

to be equivalent to:

```ruby
# frozen_string_literal: true
```




-- 
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