1 files changed, 1 insertions, 0 deletions
diff --git a/chap.scm b/chap.scm
index 1766720..dfd3c1f 100644
--- a/chap.scm
+++ b/chap.scm
@@ -22,6 +22,7 @@
 ;;; section of the string consists of consecutive numeric or
 ;;; consecutive aphabetic characters.
 
+(require 'rev4-optional-procedures)	; string-copy
 
 ;;@code{(require 'chapter-order)}
 ;;@ftindex chapter-order