This is not sorting, but something strange.
To begin with,
(rplaca (car l) …) , if
l simple list - this is nonsense. Suppose we have a list
(setf l '(3 2 1))
Visually, this can be represented, say, as (rectangles are cons):
┌───┬─────────────────────┐ │ │ ┌───┬─────────────┐ │ │ │ │ │ ┌───┬─────┐ │ │ │ 3 │ │ 2 │ │ 1 │ nil │ │ │ │ │ │ │ └───┴─────┘ │ │ │ │ └───┴─────────────┘ │ └───┴─────────────────────┘ └─┬─┘└─────────┬──────────┘ (car l) (cdr l)
I did not draw here with a chain (as usual draw, and how to display all this more correctly), but nested. With pseudographics, alas, uncomfortable in a different way.
Or, in the form of statements:
(car l) => 3 (cdr l) => (2 1) (car (cdr l)) => 2 (cdr (cdr l)) => (1) (car (cdr (cdr l))) => 1 (cdr (cdr (cdr l))) => nil
(rplaca (car l) …) you are essentially doing
(rplaca 3 …) , but
3 is not a cons. That's why it turns out "bad argument type - 3". The first argument type of
We end up with the fact that even if it were meant “to replace the first element in l (in fact,
(car l) , yes) with the minimum value in
(rplaca l (min l)) ), and then recursively sort tail ", then it will not sort. You replace the first element
l , losing the value that was there - it's not a transfer and not a permutation, but a replacement-assignment.
Once again, in detail, re-read everything that is devoted to lists in Lisp. What cons is, and how the (linked) lists are arranged, and how
rplaca (in particular, its arguments) works with examples of usage.
And, yes, please format the code more readable.