RosettaCodeData/Task/Soundex/Common-Lisp/soundex.lisp

23 lines
592 B
Common Lisp

(defun get-code (c)
(case c
((#\B #\F #\P #\V) #\1)
((#\C #\G #\J #\K
#\Q #\S #\X #\Z) #\2)
((#\D #\T) #\3)
(#\L #\4)
((#\M #\N) #\5)
(#\R #\6)))
(defun soundex (s)
(if (zerop (length s))
""
(let* ((l (coerce (string-upcase s) 'list))
(o (list (first l))))
(loop for c in (rest l)
for cg = (get-code c) and
for cp = #\Z then cg
when (and cg (not (eql cg cp))) do
(push cg o)
finally
(return (subseq (coerce (nreverse `(#\0 #\0 #\0 ,@o)) 'string) 0 4))))))