diff --git a/lib/chibi/regexp.scm b/lib/chibi/regexp.scm
index 8d4cc73d..202244a4 100644
--- a/lib/chibi/regexp.scm
+++ b/lib/chibi/regexp.scm
@@ -627,6 +627,9 @@
             (else (error "invalid sre char-set" sre)))))
      (else (error "invalid sre char-set" sre)))))
 
+(define (char-set->sre cset)
+  (list (char-set->string cset)))
+
 (define (strip-submatches sre)
   (if (pair? sre)
       (case (car sre)
diff --git a/lib/chibi/regexp.sld b/lib/chibi/regexp.sld
index d4838655..09e87c70 100644
--- a/lib/chibi/regexp.sld
+++ b/lib/chibi/regexp.sld
@@ -1,6 +1,6 @@
 
 (define-library (chibi regexp)
-  (export regexp regexp? rx regexp->sre
+  (export regexp regexp? rx regexp->sre char-set->sre
           regexp-matches regexp-matches? regexp-search
           regexp-replace regexp-replace-all
           regexp-fold regexp-extract regexp-split