diff --git a/lib/chibi/regexp.scm b/lib/chibi/regexp.scm
index 3ea8b84d..92008bc0 100644
--- a/lib/chibi/regexp.scm
+++ b/lib/chibi/regexp.scm
@@ -60,13 +60,12 @@
 (define (flag-clear a b) (bitwise-and a (bitwise-not b)))
 
 (define (char-set-ci cset)
-  (let ((res (char-set)))
-    (char-set-for-each
-     (lambda (ch)
-       (char-set-adjoin! res (char-upcase ch))
-       (char-set-adjoin! res (char-downcase ch)))
-     cset)
-    res))
+  (char-set-fold
+   (lambda (ch res)
+     (char-set-adjoin! (char-set-adjoin! res (char-upcase ch))
+                       (char-downcase ch)))
+   (char-set)
+   cset))
 
 (define (make-char-state ch flags next)
   (if (flag-set? flags ~ci?)
@@ -557,6 +556,7 @@
       ((numeric num digit) %char-set:digit)
       ((alphanumeric alphanum alnum) %char-set:letter+digit)
       ((punctuation punct) %char-set:punctuation)
+      ((symbol) %char-set:symbol)
       ((graphic graph) %char-set:graphic)
       ((word-constituent) %char-set:word-constituent)
       ((whitespace white space) %char-set:whitespace)
@@ -579,6 +579,7 @@
       ((numeric num digit) char-set:digit)
       ((alphanumeric alphanum alnum) char-set:letter+digit)
       ((punctuation punct) char-set:punctuation)
+      ((symbol) char-set:symbol)
       ((graphic graph) char-set:graphic)
       ((word-constituent) char-set:word-constituent)
       ((whitespace white space) char-set:whitespace)
@@ -613,7 +614,8 @@
            (or (string? (car sre))
                (memq (car sre)
                      '(char-set / char-range & and ~ complement - difference))
-               (and (memq (car sre) '(|\|| or))
+               (and (memq (car sre)
+                          '(|\|| or w/case w/nocase w/unicode w/ascii))
                     (every char-set-sre? (cdr sre)))))))
 
 (define (valid-sre? x)
@@ -622,32 +624,37 @@
 (define (sre->char-set sre . o)
   (let ((flags (if (pair? o) (car o) ~none)))
     (define (->cs sre) (sre->char-set sre flags))
+    (define (maybe-ci sre)
+      (if (flag-set? flags ~ci?) (char-set-ci sre) sre))
     (cond
      ((lookup-char-set sre flags))
-     ((char-set? sre) (char-set-ci sre))
-     ((char? sre) (char-set-ci (char-set sre)))
+     ((char-set? sre) (maybe-ci sre))
+     ((char? sre) (maybe-ci (char-set sre)))
      ((string? sre)
       (if (= 1 (string-length sre))
-          (string->char-set sre)
+          (maybe-ci (string->char-set sre))
           (error "only single char strings can be char-sets")))
      ((pair? sre)
       (if (string? (car sre))
-          (string->char-set (car sre))
+          (maybe-ci (string->char-set (car sre)))
           (case (car sre)
-            ((char-set) (string->char-set (cadr sre)))
+            ((char-set) (maybe-ci (string->char-set (cadr sre))))
             ((/ char-range)
              (->cs
               `(or ,@(map (lambda (x)
-                            (char-set-ci
-                             (ucs-range->char-set
-                              (char->integer (car x))
-                              (+ 1 (char->integer (cdr x))))))
+                            (ucs-range->char-set
+                             (char->integer (car x))
+                             (+ 1 (char->integer (cdr x)))))
                           (sre-flatten-ranges (cdr sre))))))
             ((& and) (apply char-set-intersection (map ->cs (cdr sre))))
             ((|\|| or) (apply char-set-union (map ->cs (cdr sre))))
             ((~ complement) (char-set-complement (->cs `(or ,@(cdr sre)))))
             ((- difference) (char-set-difference (->cs (cadr sre))
                                                  (->cs `(or ,@(cddr sre)))))
+            ((w/case) (sre->char-set (cadr sre) (flag-clear flags ~ci?)))
+            ((w/nocase) (sre->char-set (cadr sre) (flag-join flags ~ci?)))
+            ((w/ascii) (sre->char-set (cadr sre) (flag-join flags ~ascii?)))
+            ((w/unicode) (sre->char-set (cadr sre) (flag-clear flags ~ascii?)))
             (else (error "invalid sre char-set" sre)))))
      (else (error "invalid sre char-set" sre)))))
 
@@ -932,6 +939,18 @@
      start
      end)))
 
+(define (regexp-partition rx str . o)
+  (let ((start (if (pair? o) (car o) 0))
+        (end (if (and (pair? o) (pair? (cdr o))) (cadr o) (string-length str))))
+    (define (kons from md str a)
+      (let ((left (substring str from (regexp-match-submatch-start md 0))))
+        (cons (regexp-match-submatch md 0) (cons left a))))
+    (define (final from md str a)
+      (if (or (< from end) (null? a))
+          (cons (substring str from end) a)
+          a))
+    (reverse (regexp-fold rx kons '() str final start end))))
+
 (define (regexp-replace rx str subst . o)
   (let* ((start (if (and (pair? o) (car o)) (car o) 0))
          (o (if (pair? o) (cdr o) '()))
diff --git a/lib/chibi/regexp.sld b/lib/chibi/regexp.sld
index 148d6085..d1554bd9 100644
--- a/lib/chibi/regexp.sld
+++ b/lib/chibi/regexp.sld
@@ -3,7 +3,7 @@
   (export regexp regexp? valid-sre? rx regexp->sre char-set->sre
           regexp-matches regexp-matches? regexp-search
           regexp-replace regexp-replace-all
-          regexp-fold regexp-extract regexp-split
+          regexp-fold regexp-extract regexp-split regexp-partition
           regexp-match? regexp-match-count
           regexp-match-submatch regexp-match-submatch/list
           regexp-match-submatch-start regexp-match-submatch-end
@@ -43,6 +43,8 @@
         (char-set-intersection char-set:ascii char-set:letter+digit))
       (define %char-set:punctuation
         (char-set-intersection char-set:ascii char-set:punctuation))
+      (define %char-set:punctuation
+        (char-set-intersection char-set:ascii char-set:symbol))
       (define %char-set:graphic
         (char-set-intersection char-set:ascii char-set:graphic))
       (define %char-set:whitespace
@@ -69,7 +71,7 @@
       (define (string-start-arg s o)
         (if (pair? o) (string-index->offset s (car o)) 0))
       (define (string-end-arg s o)
-        (if (pair? o) (string-index->offset (car o)) (string-length s)))
+        (if (pair? o) (string-index->offset s (car o)) (string-length s)))
       (define string-cursor=? =)
       (define string-cursor<? <)
       (define string-cursor<=? <=)