Negating a parameter: "Unable to resolve symbol: -x in this context"

Question

(defn my-fun [x]
    (println -x))

Executing this code, i get:

Unable to resolve symbol: -x in this context

Why can't i just invert x?

Answer 1

Dashes are valid symbols in names.

To do a unary negation, you'd treat it like you would any other function:

(println (- x))

From the docs:

If no ys are supplied, returns the negation of x . . .