source: tags/dso-lex-0.2.1/example.lisp

#|
Copyright (C) 2007  David Owen <dsowen@fugue88.ws>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
|#



(require '#:cl-ppcre)
(require '#:dso-lex)

(use-package '(#:cl-ppcre #:dso-lex))



(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
  ("," comma)
  ("[^\"',]+" value)
  ("'(?:[^']|'')*'" value un-squote)
  ("\"(?:[^\"]|\"\")*\"" value un-dquote))

(defun scan-all (input)
  (labels ((scan (start tokens)
             (if (> (length input) start)
                 (multiple-value-bind (class image remainder)
                     (scan-csv input start)
                   (when class
                     (scan remainder (cons (cons class image) tokens))))
                 (nreverse tokens))))
    (scan 0 '())))

(scan-all "no quotes,'a ''quote''',\"another \"\"quote\"\"\"")