diff --git a/trans.scm b/trans.scm
index 43aeecc2..f349a4e9 100644
--- a/trans.scm
+++ b/trans.scm
@@ -72,6 +72,13 @@
   (define (char>?  c1 c2 . cs) (Cyc-bin-op-char >  c1 (cons c2 cs)))
   (define (char<=? c1 c2 . cs) (Cyc-bin-op-char <= c1 (cons c2 cs)))
   (define (char>=? c1 c2 . cs) (Cyc-bin-op-char >= c1 (cons c2 cs)))
+  (define (char-upcase c)
+    (if (char-lower-case? c)
+      (integer->char
+        (- (char->integer c)
+            (- (char->integer #\a)
+               (char->integer #\A))))
+      c))
   (define (char-alphabetic? c) (and (char>=? c #\A) (char<=? c #\z))) ;; ASCII-only
   (define (char-upper-case? c) (and (char>=? c #\A) (char<=? c #\Z))) ;; ASCII-only
   (define (char-lower-case? c) (and (char>=? c #\a) (char<=? c #\z))) ;; ASCII-only