Regex Tester & Validator

Matches lines consisting entirely of uppercase letter segments separated by single underscores (SCREAMING_SNAKE_CASE), such as THIS_IS_MY_MACRO or MAX_RETRY_COUNT. With the multiline flag, each line is validated independently, making it ideal for validating constant or macro names in code. It rejects leading/trailing underscores, consecutive underscores, digits, and lowercase letters.