equivalent to the set \regexp{[\textasciicircum\ \e t\e n\e r\e f\e v]}.
\item[\code{\e w}]When the \constant{LOCALE} and \constant{UNICODE}
-flags are not specified,
-matches any alphanumeric character; this is equivalent to the set
+flags are not specified, matches any alphanumeric character and the
+underscore; this is equivalent to the set
\regexp{[a-zA-Z0-9_]}. With \constant{LOCALE}, it will match the set
-\regexp{[0-9_]} plus whatever characters are defined as letters for
+\regexp{[0-9_]} plus whatever characters are defined as alphanumeric for
the current locale. If \constant{UNICODE} is set, this will match the
characters \regexp{[0-9_]} plus whatever is classified as alphanumeric
in the Unicode character properties database.
flags are not specified, matches any non-alphanumeric character; this
is equivalent to the set \regexp{[{\textasciicircum}a-zA-Z0-9_]}. With
\constant{LOCALE}, it will match any character not in the set
-\regexp{[0-9_]}, and not defined as a letter for the current locale.
+\regexp{[0-9_]}, and not defined as alphanumeric for the current locale.
If \constant{UNICODE} is set, this will match anything other than
-\regexp{[0-9_]} and characters marked at alphanumeric in the Unicode
+\regexp{[0-9_]} and characters marked as alphanumeric in the Unicode
character properties database.
\item[\code{\e Z}]Matches only at the end of the string.