[ :x x x ] :dup

[
    dup!
    [dup! 1 -! factorial! *!]
    [:_ 1]
    if!
]
:factorial

[
    dup! print!
    "! = " print!
    factorial!
    println!
]
:do-factorial

1 do-factorial!
2 do-factorial!
3 do-factorial!
4 do-factorial!
5 do-factorial!
6 do-factorial!
7 do-factorial!
8 do-factorial!
9 do-factorial!