Tweak example in Function Indirection node in the lispref manual

* doc/lispref/eval.texi (Function Indirection): Make example more
robust (bug#49647).  Suggested by Scott Marks
<scott.c.marks@gmail.com>.

diff --git a/doc/lispref/eval.texi b/doc/lispref/eval.texi
index 448b8ae17abeb4ed74ced51c76478d5df9cce7c4..7893895eee9e5ce6a5427b1dbba24d7917d732c1 100644 (file)
--- a/doc/lispref/eval.texi
+++ b/doc/lispref/eval.texi
@@ -350,7 +350,8 @@ Here is how you could define @code{indirect-function} in Lisp:
 
 @example
 (defun indirect-function (function)
-  (if (symbolp function)
+  (if (and function
+           (symbolp function))
       (indirect-function (symbol-function function))
     function))
 @end example