add note that codex is used for documentation.

README.txt

@@ -53,3 +53,13 @@ Miscellanea
 * mkkw
 * zip
 * defclass!
+
+Documentation
+=============
+
+Documentation is generated with codex [1]:
+
+    CL-USER> (ql:quickload :codex) ;; if not installed
+    (:CODEX)
+    CL-USER> (codex:document :kutils)
+    NIL

kutils.asd

@@ -11,4 +11,3 @@
                (:file "kutils")
                (:file "kutils-hash-tables")
 	       (:file "macros")))
-

kutils.lisp

@@ -175,3 +175,9 @@ those that do not satisfy @c(pred)."
     ((listp seq)   (partition-list pred seq))
     ((vectorp seq) (partition-vector pred seq))
     (t nil)))
+
+(defun in-range (number low high)
+  "Returns T if LOW >= NUMBER <= HIGH."
+  (and
+   (<= number high)
+   (>= number low)))