macro
boot.janet on line 1957, column 1
(varfn name & body)
Create a function that can be rebound. varfn has the same signature
as defn, but defines functions in the environment as vars. If a var
'name' already exists in the environment, it is rebound to the new
function. Returns a function.
(defn greet-me [] (print "hey programmer!"))
(defn greet-stranger [] (print "hey stranger!"))
(varfn greet [] (greet-me))
(greet) # prints "hey programmer!"
(varfn greet [] (greet-stranger))
(greet) # prints "hey stranger!"
# kind of analogous to (def greet (fn [] (some-thunk))), but with built-in
# sugar to automatically update 'greet' if varfn is called with a name
# already bound