A Kawa user just discovered a bug in string-contains, which I tracked
down to the reference implementation of make-kmp-restart-vector.

string-parse-start+end is documented to return three values:
"rest start end", but in make-kmp-restart-vector its result is bound
to two variables (start end). I found the same issue in
string-kmp-partial-search, which also attempts to capture only the
"start" and "end" values.

The fix in both places is to call string-parse-final-start+end instead,
which strips off the first unwanted rest value from string-parse-start
+end.

--- srfi-13.scm	2006-11-21 16:18:11.000000000 -0500
+++ srfi-13-fixed.scm	2011-12-22 15:17:59.000000000 -0500
@@ -1381,7 +1381,7 @@
    (let-optionals* maybe-c=+start+end
                    ((c= char=? (procedure? c=))
  		   ((start end) (lambda (args)
-				  (string-parse-start+end make-kmp-restart-vector
+				  (string-parse-final-start+end make-kmp-restart-vector
  							  pattern args))))
      (let* ((rvlen (- end start))
  	   (rv (make-vector rvlen -1)))
@@ -1450,7 +1450,7 @@
  		  ((c=      char=? (procedure? c=))
  		   (p-start 0 (and (integer? p-start) (exact? p-start) (<= 0 p-
start)))
  		   ((s-start s-end) (lambda (args)
-				      (string-parse-start+end string-kmp-partial-search
+				      (string-parse-final-start+end string-kmp-partial-search
  							      s args))))
      (let ((patlen (vector-length rv)))
        (check-arg (lambda (i) (and (integer? i) (exact? i) (<= 0 i)
(< i patlen)))

--
Jamison Hope
The PTR Group
www.theptrgroup.com