Regular expression language preview
1. Named groups and quantifiers
a date pattern with named capture groups
horizon-dark
^(?<year>\d{4})-(?<month>\d{2})-\d{2}\s+#\s*optional commentatom-one-dark
^(?<year>\d{4})-(?<month>\d{2})-\d{2}\s+#\s*optional commentgithub-dark
^(?<year>\d{4})-(?<month>\d{2})-\d{2}\s+#\s*optional commentdracula
^(?<year>\d{4})-(?<month>\d{2})-\d{2}\s+#\s*optional commentnord
^(?<year>\d{4})-(?<month>\d{2})-\d{2}\s+#\s*optional commentgithub
^(?<year>\d{4})-(?<month>\d{2})-\d{2}\s+#\s*optional comment2. Character classes and Unicode properties
POSIX classes, ranges, and \p{...} escapes
horizon-dark
(?:https?|ftp):\/\/[\w.-]+\.[a-z]{2,}
[[:alpha:]]+\d*\.?\p{L}*atom-one-dark
(?:https?|ftp):\/\/[\w.-]+\.[a-z]{2,}
[[:alpha:]]+\d*\.?\p{L}*github-dark
(?:https?|ftp):\/\/[\w.-]+\.[a-z]{2,}
[[:alpha:]]+\d*\.?\p{L}*dracula
(?:https?|ftp):\/\/[\w.-]+\.[a-z]{2,}
[[:alpha:]]+\d*\.?\p{L}*nord
(?:https?|ftp):\/\/[\w.-]+\.[a-z]{2,}
[[:alpha:]]+\d*\.?\p{L}*github
(?:https?|ftp):\/\/[\w.-]+\.[a-z]{2,}
[[:alpha:]]+\d*\.?\p{L}*3. Lookaround and backreferences
lookahead/lookbehind assertions, inline comments, and \k<name>
horizon-dark
(?=foo)(?<=bar)(?!baz)(?<!qux)
(?#inline comment)\k<year>\1atom-one-dark
(?=foo)(?<=bar)(?!baz)(?<!qux)
(?#inline comment)\k<year>\1github-dark
(?=foo)(?<=bar)(?!baz)(?<!qux)
(?#inline comment)\k<year>\1dracula
(?=foo)(?<=bar)(?!baz)(?<!qux)
(?#inline comment)\k<year>\1nord
(?=foo)(?<=bar)(?!baz)(?<!qux)
(?#inline comment)\k<year>\1github
(?=foo)(?<=bar)(?!baz)(?<!qux)
(?#inline comment)\k<year>\1