In trying to track down a problem matching a cxml-rng pattern in soiree, I came across the following somewhat odd behavior in cl-pppcre. In perl, I see: (sly@barbaresco):~/projects/soiree$ echo "Ta" | perl -ne 'print if /^T(a)|(b)$/' Ta (sly@barbaresco):~/projects/soiree$ echo "Tb" | perl -ne 'print if /^T(a)|(b)$/' Tb Whereas with cl-ppcre, I see: SOIREE-ICALENDAR> (cl-ppcre:scan-to-strings "^T(a)|(b)$" "Ta") "Ta" #("a" NIL) SOIREE-ICALENDAR> (cl-ppcre:scan-to-strings "^T(a)|(b)$" "Tb") "b" #(NIL "b") Parsing the string suggests that the order of operations may be different in cl-ppcre than in perl. Is this intentional? SOIREE-ICALENDAR> (cl-ppcre:parse-string "^T(a)|(b)$") (:ALTERNATION (:SEQUENCE :START-ANCHOR #\T (:REGISTER #\a)) (:SEQUENCE (:REGISTER #\b) :END-ANCHOR)) thanks, Cyrus