factorial-power ( x n h -- (x)n(h) )

Vocabulary

math.factorials

Inputs

x	an object
n	an object
h	an object

Outputs

(x)n(h)

an object

Definition

USING: combinators kernel math math.functions ranges sequences ;

IN: math.factorials

: factorial-power ( x n h -- (x)n(h) )
    {
        { 1 [ falling-factorial ] }
        { 0 [ ^ ] }
        [
            over 0 < [
                [ [ nip + ] [ swap neg * + ] 3bi ] keep <range>
                product recip
            ] [
                neg [ [ dupd 1 - ] [ * ] bi* + ] keep <range>
                product
            ] if
        ]
    } case ;