The length of nil value

[iNPRwANG]

This is code:

Code Select Expand


(setq mylst '(nil nil nil nil nil nil nil nil nil nil nil nil))
(dolist (item mylst) (println (length item)))


Why the result is:



3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

[rickyboy]

Because (length 'nil) is 3.



On the other hand, (length nil) is 0.

[Lutz]

Length applied to a symbol returns the length of the symbol name:



http://www.newlisp.org/downloads/newlisp_manual.html#length">http://www.newlisp.org/downloads/newlis ... tml#length">http://www.newlisp.org/downloads/newlisp_manual.html#length

[iNPRwANG]

OK, thx.

The difference with common lisp is: In common lisp the (length 'nil) is zero, and in newlisp is the symbols length.