(print (toString "abc"))  # "abc"
(print (toString 1))  # "1"
(print (toString (fun () ())))  # "Function@1"
(print (toString print))  # "CProcedure"
(print (toString []))  # "[]"
(let x 1) (print (toString (fun (&x) ())))  # "(.x=1)"
(print (toString (dict 1 2 3 4)))  # "{1: 2, 3: 4}"
(print (toString nil))  # "nil"
(print (toString true))  # "true"
(print (toString false))  # "false"

(print (type "abc"))  # "String"
(print (type 1))  # "Number"
(print (type (fun () ())))  # "Function"
(print (type print))  # "CProc"
(print (type []))  # "List"
(let x 1) (print (type (fun (&x) ())))  # "Closure"
(print (type (dict 1 2 3 4)))  # "Dict"
(print (type nil))  # "Nil"
(print (type true))  # "Bool"
(print (type false))  # "Bool"

(print (nil? "abc"))  # false
(print (nil? 1))  # false
(print (nil? (fun () ())))  # false
(print (nil? print))  # false
(print (nil? []))  # false
(print (nil? (dict 1 2 3 4)))  # false
(print (nil? nil))  # true
(print (nil? true))  # false
(print (nil? false))  # false

(print (< "abc" "def"))  # true, string are compared lexicographically
(print (< 2 1))  # false
(print (> 3 -5.5)  # true
(print (> "Hello" ""))
(print (<= [] [1 2]))  # true, lists are compared lexicographically
(print (<= [1 2] [1 0]))  # false
(print (<= [1 2] [10]))  # true
(print (>= 5 5))  # true
(print (= false 5))  # false
(print (!= false 5))  # true

(print (not ""))  # true
(print (not "a"))  # false
(print (not 0))  # true
(print (not 1))  # false
(print (not []))  # true
(print (not [1 2]))  # false
(print (not nil))  # true
(print (not true))  # false
(print (not false))  # true
(print (not (dict)))  # true
(print (not (dict "a" 1)))  # false

(let x 1)
(let b "hello")
(let closure (fun (&x &b) ()))
(print (hasField closure "x"))  # true
(print (hasField closure "b"))  # true
(print (hasField closure "B"))  # false, field names are case-sensitive