print! sep:="" # OK
print! 1, "", sep:="" # OK
print! end:="", sep:="" # OK
print! 1, end:="", sep:="" # OK

add x: Int, y: Int = x + y
print! add 1, 1 # OK
print! add x:=1, y:=2 # OK
print! add y:=1, x:=2 # OK
print! add 1, y:=1 # OK
print! add() # ERR, missing argument x, y
print! add 1 # ERR, missing argument y
print! add y:=1 # ERR, missing argument x
print! add x:=1, y:="" # ERR, the type of y is wrong
print! add x:=1, y:=2, z:=1 # ERR, z is unexpected
print! add x:=1, y:=2, x:=2 # ERR, x is passed twice
print! add x:=1, y:=2, x:=2, z:=1 # ERR, x is passed twice, z is unexpected
print! add "", y:=1 # ERR, the type of x is wrong
print! add 1, 1, 1 # ERR, too many args
print! add 1, 1, y:=1 # ERR, too many args
print! add "", y:=1, x:=1 # ERR, the type of x is wrong, x is passed twice (or args are too many)
print! add "", y:="" # ERR, the types of x, y are wrong

sub x: Int, y: Int := 0 = x - y
print! sub 1 # OK
print! sub 1, 1 # OK
print! sub x:=1, y:=2 # OK
print! sub x:=1 # OK
print! sub y:=1 # ERR, missing argument x
print! sub 1, 1, y:=2 # ERR, too many args

for! {"a": 1}, (i, s #[ ERR ]#) =>
    print! i

d = !{ "a": 1 }
d.insert! "b", 2, 3 # ERR, too many args
d.insert! "c" # ERR, missing argument value