From: danieldasilvaferreira@... Date: 2018-01-19T03:10:27+00:00 Subject: [ruby-core:84929] [Ruby trunk Feature#14183] "Real" keyword argument Issue #14183 has been updated by dsferreira (Daniel Ferreira). It���s not clear for me all the implications of this change. Would it be possible to exemplify the before and after behaviours in the description? It feels to me that with this implementation it would be possible to consider both symbols and strings as keys for the keywords hash. Would it be a possibility? The dynamic generation of keywords hashes would be positively impacted with that move. ---------------------------------------- Feature #14183: "Real" keyword argument https://bugs.ruby-lang.org/issues/14183#change-69638 * Author: mame (Yusuke Endoh) * Status: Open * Priority: Normal * Assignee: * Target version: Next Major ---------------------------------------- In RubyWorld Conference 2017 and RubyConf 2017, Matz officially said that Ruby 3.0 will have "real" keyword arguments. AFAIK there is no ticket about it, so I'm creating this (based on my understanding). In Ruby 2, the keyword argument is a normal argument that is a Hash object (whose keys are all symbols) and is passed as the last argument. This design is chosen because of compatibility, but it is fairly complex, and has been a source of many corner cases where the behavior is not intuitive. (Some related tickets: #8040, #8316, #9898, #10856, #11236, #11967, #12104, #12717, #12821, #13336, #13647, #14130) In Ruby 3, a keyword argument will be completely separated from normal arguments. (Like a block parameter that is also completely separated from normal arguments.) This change will break compatibility; if you want to pass or accept keyword argument, you always need to use bare `sym: val` or double-splat `**` syntax: ``` # The following calls pass keyword arguments foo(..., key: val) foo(..., **hsh) foo(..., key: val, **hsh) # The following calls pass **normal** arguments foo(..., {key: val}) foo(..., hsh) foo(..., {key: val, **hsh}) # The following method definitions accept keyword argument def foo(..., key: val) end def foo(..., **hsh) end # The following method definitions accept **normal** argument def foo(..., hsh) end ``` I think here is a transition path: * Ruby 2.6 (or 2.7?) will output a warning when a normal argument is interpreted as keyword argument, or vice versa. * Ruby 3.0 will use the new semantics. -- https://bugs.ruby-lang.org/ Unsubscribe: