I'm apparently too stupid for you :). Please excuse my ignorance. Why can't you do something like the below?
(defun swap (x y) (y x))
Then you can call it like:
(swap (2 3)) => (3 2)
(defun swap (x y) (y x))
Then you can call it like:
(swap (2 3)) => (3 2)
(defn swap [x]
(list (second x) (first x) (last x)))
(swap (1 + 2))
=>Exception! 1 isn't a function.
So we quoted it in the function call by putting ' in front of the list '(1 + 2):
(swap '(1 + 2))
=> (+ 1 2)
So if I was to
(+ (swap '(1 + 2)) (swap '(3 + 4)))
=> Crashes! Can't convert alist to a number.
(+ '(+ 1 2) '(+ 3 4))
(+ (swap (1 + 2)) (swap (3 + 4)))
=> 10
(swap (1 + 2))
(+ 1 2)
You could do `(defn swap [the-list] ((second the-list) (first the-list)))` (which would invoke the second item as a function on the first item). It comes down to is the list a literal list as a parameter to something or is the first item a function to be invoked.