@samp{[a-m-z]} should be avoided.
A character alternative can also specify named character classes
-(@pxref{Char Classes}). This is a POSIX feature. For example,
-@samp{[[:ascii:]]} matches any @acronym{ASCII} character.
-Using a character class is equivalent to mentioning each of the
-characters in that class; but the latter is not feasible in practice,
-since some classes include thousands of different characters.
-A character class should not appear as the lower or upper bound
-of a range.
+(@pxref{Char Classes}). For example, @samp{[[:ascii:]]} matches any
+@acronym{ASCII} character. Using a character class is equivalent to
+mentioning each of the characters in that class; but the latter is not
+feasible in practice, since some classes include thousands of
+different characters. A character class should not appear as the
+lower or upper bound of a range.
The usual regexp special characters are not special inside a
character alternative. A completely different set of characters is