     return mc
   }
 
-  /// Classify a given terminal character
+  /// Classify a given terminal character.
+  ///
+  /// Terminal -> Anchor | MetaChar | SpecialCharEscape | Character
+  ///
+  /// If .ignoreWhitespace:
+  /// ' ' -> Trivia
+  ///
   static func classifyTerminal(
     _ t: Character,
     fromEscape escaped: Bool,

      return nil
    }
  }
  private static func classifyAsAnchor(
    _ t: Character, fromEscape escaped: Bool, inCustomCharClass: Bool
  ) -> Anchor? {

      return nil
    }
  }

  /// Classify a meta-character.
  ///
  /// In a custom character class:
  /// MetaChar -> '[' | ']' | '-' | '^'
  ///
  /// Otherwise:
  /// MetaChar -> '[' | '*' | '?' | '|' | '(' | ')' | '.' | ':'
  ///
  private static func classifyAsMetaChar(
    _ t: Character, inCustomCharClass: Bool
  ) -> Token.MetaCharacter? {
