(defun snip (s) (subseq s 1 (1- (length s))))
(defun un-squote (s) (regex-replace-all "''" (snip s) "'"))
(defun un-dquote (s) (regex-replace-all "\"\"" (snip s) "\""))
(deflexer scan-csv (:priority-only t)
("[^\"',]+" value)
("'(?:[^']|'')*'" value un-squote)
("\"(?:[^\"]|\"\")*\"" value un-dquote)
("," comma))
See the distribution for a more complete example.
ASDF-install package (obsolete) http://download.fugue88.ws/lex/dso-lex-0.3.2.tar.gz, or see the project page.