when test of while is nil , it does not run `print' following it.
who  does print nil ?

or  if all function will print its return value ?

thanks

2009/7/5 Glenn Morris <rgm@gnu.org>

[Please use "reply to all".]

waterloo wrote (on Sun, 5 Jul 2009 at 10:13 +0800):

> yes,it is clearer . thanks
>
> In 11.1.2 An Example:`print-elements-of-list', I can not understand why
> there is a `nil' in the context .

This is explained at the end of the section:

 Since the last expression in the function is the `while' loop, and
 since `while' loops always return `nil', a `nil' is printed after the
 last element of the list.