There are currently 6 built-in variables:
Graphemematches a single extended grapheme cluster. It compiles to the regex
\X. Note that this functionality is not available in all regex flavors.
Gis an alias for
Codepointmatches a single Unicode code point. It compiles to the regex
Cis an alias for
Start: Matches the start of the string. Equivalent to
End: Matches the end of the string. Equivalent to