Add #decorative?, fix comment group qtf parsing

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `Regexp::Expression::Shared#{capturing?,comment?}`
   * previously only available on capturing and comment groups
+- `Regexp::Expression::Shared#{decorative?}`
+  * true for non-functionals: comment groups and comments and whitespace in x-mode
 - `Regexp::Expression::Shared#parent`
 - support calling `Subexpression#{each_expression,flat_map}` with a one-argument block
   * in this case, only the expressions are passed to the block, no indices
@@ -24,6 +26,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   * e.g. in `/(?x:(?#hello)) /`, the x-option wrongly applied to the whitespace
 - fixed nested comment groups breaking conditionals
   * e.g. in `/(a)(?(1)b|c(?#hello)d)e/`, the 2nd conditional branch included "e"
+- fixed quantifiers after comment groups being mis-assigned to that group
+  * e.g. in `/a(?#foo){3}/` (matches 'aaa')
 - fixed scanner accepting unmatched closing parentheses ')'
   * these are a `SyntaxError` in Ruby, so could only be passed as a String
   * they now raise a `Regexp::Scanner::ScannerError`

lib/regexp_parser/expression/methods/tests.rb

@@ -108,7 +108,11 @@ def capturing?
     end
 
     def comment?
-      false # overridden to be true e.g. in Expression::Group::Comment
+      false # overridden to be true in Expression::{Comment,Group::Comment}
+    end
+
+    def decorative?
+      false # overridden to be true in Expression::{FreeSpace,Group::Comment}
     end
 
     def optional?

lib/regexp_parser/parser.rb

@@ -478,7 +478,7 @@ def property(token)
   end
 
   def quantifier(token)
-    target_node = node.expressions.reverse.find { |exp| !exp.is_a?(FreeSpace) }
+    target_node = node.expressions.reverse.find { |exp| !exp.decorative? }
     target_node or raise ParserError, "No valid target found for '#{token.text}'"
 
     # in case of chained quantifiers, wrap target in an implicit passive group

spec/expression/methods/tests_spec.rb

@@ -151,13 +151,14 @@
     [0] => [capturing?: true],
     [1] => [capturing?: false]
 
-  # test #comment?
-  include_examples 'parse', /(a)(?#b)c#d/x,
+  # test #comment?, #decorative?
+  include_examples 'parse', /(a)(?#b)c # d/x,
     []  => [comment?: false],
     [0] => [comment?: false],
-    [1] => [comment?: true],
+    [1] => [comment?: true, decorative?: true],
     [2] => [comment?: false],
-    [3] => [comment?: true]
+    [3] => [comment?: false, decorative?: true],
+    [4] => [comment?: true, decorative?: true]
 
   # test #optional?
   include_examples 'parse', /a?/,     [0] => [optional?: true]

spec/parser/groups_spec.rb

@@ -14,6 +14,11 @@
     3 => [:group, :comment, Group::Comment, capturing?: false, comment?: true],
     5 => [:group, :comment, Group::Comment, capturing?: false, comment?: true]
 
+  include_examples 'parse', /a(?# is for apple){3}/,
+    [0]     => [Literal, text: 'a', quantified?: true],
+    [0, :q] => [Quantifier, text: '{3}'],
+    [1]     => [Group::Comment, text: '(?# is for apple)', quantified?: false]
+
   if ruby_version_at_least('2.4.1')
     include_examples 'parse', 'a(?~b)c(?~d)e',
       1 => [:group, :absence, Group::Absence],