I realise that there is a set of character class operators eg [:word:] and we have the \< \> anchors but I'd find it useful if the Regex engine also supported some other metasequences that are common in other engines...
\b Matches a word boundary, such as a space. "ea*r\b" matches the "er" in "never early."
\B Matches a nonword boundary. "ea*r\B" matches the "ear" in "never early."
\d Matches a digit character. Equivalent to [0-9].
\D Matches a nondigit character. Equivalent to [^0-9].
\s Matches any white space including space, tab, form-feed, and so on. Equivalent to [ \f\n\r\t\v]
\S Matches any nonwhite space character. Equivalent to [^ \f\n\r\t\v]
\v Matches a vertical tab character.
\w Matches any word character including underscore. Equivalent to [A-Za-z0-9_].
\W Matches any nonword character. Equivalent to [^A-Za-z0-9_].
Cheers,
Andrew