From: nobu@... Date: 2020-02-29T07:25:32+00:00 Subject: [ruby-core:97308] [Ruby master Feature#15722] `Kernel#case?` Issue #15722 has been updated by nobu (Nobuyoshi Nakada). osyo (manga osyo) wrote in #note-6: > I think this is closer to the syntax of `case when`. > And what about adding a oneline `when` like a oneline `in` ? > > ```ruby > bar # => "bar" > flag1 = case bar; when "foo", "bar", "baz"; true; end # => true > flag2 = case bar; when Symbol, String; true; end # => true > > flag1 = bar when "foo", "bar", "baz" # => true > flag2 = bar when Symbol, String # => true > ``` As a `case expr` statement doesn't need a terminator (newline or semicolon) before `when`, it conflicts with the current syntax. ---------------------------------------- Feature #15722: `Kernel#case?` https://bugs.ruby-lang.org/issues/15722#change-84435 * Author: sawa (Tsuyoshi Sawada) * Status: Feedback * Priority: Normal ---------------------------------------- I often want to use `===` to match a single object on the right side against multiple objects on the left, as is used in `case`-constructions, just to return a truth value, and end up writing like this: ```ruby bar # => "bar" flag1 = case bar; when "foo", "bar", "baz"; true; end # => true flag2 = case bar; when Symbol, String; true; end # => true ``` I propose `Kernel#case?` that should work like this: ```ruby bar # => "bar" bar.case?("foo", "bar", "baz") # => true bar.case?("qux") # => false bar.case?(Symbol, String) # => true bar.case?(Array) # => false bar.case? # => false ``` It is similar to Rails' `in?`, but it differs from it in that it uses `===` for comparison, not `==`. Or, alternatively, allowing `Kernel#instance_of?` and `Kernel#kind_of?` to allow multiple arguments may be a compromise. -- https://bugs.ruby-lang.org/ Unsubscribe: