eXist-db

Is there a definition of the Punctation class in XPath regex, and thus a
definition of \w ? I searched the specs but could not locate it. Its not the
same as the POSIX charatacters, at least in eXist as the following code shows
since all these are not punctuation.

    $+<=>^|~

let $punct := concat("&amp;!'#$%()*+,-./:;<=>?@[/]^_|~{}",'"')
for $i in 1 to string-length($punct)
let $char := substring($punct,$i,1)
let $match := matches($char,"\p{P}")
where not($match)
return
  $char