Issue #19417 has been updated by naruse (Yui NARUSE). The document is wrong. The definition of `word` is defined in Unicode® Technical Standard #18 UNICODE REGULAR EXPRESSIONS. https://unicode.org/reports/tr18/#word ---------------------------------------- Bug #19417: Regexp \p{Word} and [[:word:]] do not match Unicode Other_Number character https://bugs.ruby-lang.org/issues/19417#change-102252 * Author: ObjectBoxPC (Philip Chung) * Status: Open * Priority: Normal * ruby -v: 3.2.0 * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- According to the [documentation for Regexp](https://ruby-doc.org/3.2.0/Regexp.html), `\p{Word}` and `[[:word:]]` both match a character in one of the following Unicode general categories: Letter, Mark, Number, Connector_Punctuation. However, neither matches U+00B2, which is in the Other_Number category (which is a subcategory of Number). ``` ruby puts "Ruby version: %s" % RUBY_VERSION puts "\p{Word} matches? %s" % /\p{Word}/u.match?("\u00B2") puts "[[:word:]] matches? %s" % /[[:word:]]/u.match?("\u00B2") puts "Is a Number charater? %s" % /\p{Number}/u.match?("\u00B2") puts "Is an Other_Number character? %s" % /\p{Other_Number}/u.match?("\u00B2") ``` Expected output: ``` Ruby version: 3.2.0 p{Word} matches? true [[:word:]] matches? true Is a Number charater? true Is an Other_Number character? true ``` Actual output: ``` Ruby version: 3.2.0 p{Word} matches? false [[:word:]] matches? false Is a Number charater? true Is an Other_Number character? true ``` I notice that the [upstream Onigmo library doc](https://github.com/k-takata/Onigmo/blob/master/doc/RE) defines the `[[:word:]]` class as "Letter | Mark | Decimal_Number | Connector_Punctuation", meaning that it only matches certain number characters (which would exclude U+00B2). I am not sure how `\p{Word}` is defined though. But perhaps the documentation needs to be changed? -- https://bugs.ruby-lang.org/