[#104307] Float truncate — Eustáquio Rangel <eustaquiorangel@...>
Hi!
4 messages
2021/06/16
[ruby-core:104209] [Ruby master Feature#17785] Allow named parameters to be keywords
From:
harrison.bachrach@...
Date:
2021-06-09 00:08:16 UTC
List:
ruby-core #104209
Issue #17785 has been updated by harrisonb (Harrison Bachrach).
This feels related to [this proposal](https://bugs.ruby-lang.org/issues/16460) I submitted ~1.5 years ago concerning external/internal names for keyword parameters as it would solve this problem somewhat more elegantly:
```ruby
# Only one possible syntax--see above proposal for alternatives
def check(arg, class class_:)
arg.is_a?(class_)
end
check(42, class: Integer) # => true
```
----------------------------------------
Feature #17785: Allow named parameters to be keywords
https://bugs.ruby-lang.org/issues/17785#change-92388
* Author: marcandre (Marc-Andre Lafortune)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
We should allow named parameters to be keywords and use add a trailing `_` to the corresponding variable:
```ruby
def check(arg, class:)
arg.is_a?(class_)
end
check(42, class: Integer) # => true
```
Currently, if we want such an API we have to use `**rest`:
```ruby
def check(arg, **rest)
class_ = rest.fetch(:class) { raise ArgumentError('missing keyword: :class')}
if rest.size > 1
unknown = rest.keys - [:class]
raise ArgumentError("unknown keyword(s): :#{unknown.join(', :')})
end
arg.is_a?(class_)
end
```
This is very verbose, much less convenient, much less readable, prevents `steep` from generating the proper signature, etc.
We should do the same for pattern match.
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