I think he is asking for an ascii character operator for evaluation purposes. I'm sure you can use regex along with a custom $ischar identifier for that matter:
Code:
alias -l ischar if ($regex($1-,/(\W+)/S)) return $regml(1) 
on *:TEXT:*:?:if ($ischar($1-)) echo -s WARNING: $nick just used $+(",$v1,") in private.
P.S. I know using an alias is unnecessary, but since westor's brought the $v1 up...I thought it'd be for the best.