Re: some more material on the Lisp data/code psychedelia

[Emanuel Berg]

Emanuel Berg <embe8573@student.uu.se> writes:

>> You can also use ‘last’ and ‘setcar’ (via ‘incf’)
>> for this: (defun increment-last (ls) (when ls (incf
>> (car (last ls))) ls)) Non-recursive means less stack
>> required for long forms.  Destructive style is
>> sketchy but the func is already squarely in DWR
>> territory...
>
> That's interesting:
>
> (setq *ls* '(1 2 3))
>
> (defun inc-last (ls) (when ls (incf (car (last ls)))
> ls) )
>
> (inc-last *ls*) *ls* ; => '(1 2 4) after the above line
>
> I wonder how the "destructiveness" can be used with
> respect to the rest of the demo...?

How about:

(defun change-me ()
  (incf (car (last (symbol-function 'change-me))))
  1)

(change-me) ; hit `C-x e' repeatedly here

Ironic thing is, first version, while not as good,
actually showed the duality in a cool way. The above
version just looks stiff, its purpose unclear.

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