Update only definition of expression substitution

larcs.org

@@ -187,10 +187,10 @@ Of the various types, there are three atomic types, ~<number>~, ~<variable>~ and
     (declare (ignore expression))
     t)
 
-  (defmethod subsitute-expression (expression with (in <atomic>))
-    (if (eqal expression in)
-        with
-        in))
+  (defmethod substitute-expression (replace replacement (expression <atomic>))
+    (if (eqal expression replace)
+        replacement
+        expression))
 #+END_SRC
 
 *** DONE Numbers