Regex Editor & Tester

This regex defines a custom zero-width boundary (named CCT) that matches transitions between four specific character classes: uppercase letters, lowercase letters, digits, and non-alphanumeric characters. Unlike the standard word boundary (`\b`), which only separates word characters from non-word characters, this pattern detects shifts between any of these distinct groups. It is particularly useful for tokenizing mixed-format strings, such as camelCase or snake_case identifiers, and is often applied in text parsing or syntax highlighting.