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Checking for an empty list: `nullp'
The abstraction `nullp' tests whether a list is empty.
The list to be testet must be terminated by `nil'.
![\begin{lstlisting}[language=Scm]{}
(define nullp (lambda (l)
(l (lambda (hd tl)
false))))
\end{lstlisting}](img95.gif)
![\begin{lstlisting}[language=Scm]{}
(define l1 (cons two (cons three nil)))
;
(bdisp! (nullp l1))
--> false
(bdisp! (nullp nil))
--> true
\end{lstlisting}](img96.gif)
Georg P. Loczewski
2004-03-05