\w doesn't match non-ASCII letters

oocms=# select 'ф' ~ '^\\w$';
?column?
----------
f
(1 запись)

or

oocms=# select 'ä' ~ '^\\w$';
?column?
----------
f
(1 запись)

both should return true, as does

oocms=# select 'n' ~ '^\\w$';
?column?
----------
t
(1 запись)

Thanks.

--
Markus Bertheau <twanger(at)bluetwanger(dot)de>