find-pred-loop ( ... i n seq quot: ( ... elt -- ... calc ? ) -- ... calc/f i/f elt/f )

Vocabulary

sequences.extras

Inputs

i	an integer
n	an integer
seq	a sequence
quot	a quotation

Outputs

calc/f	an object
i/f	an integer or f
elt/f	an object

Definition

USING: generalizations kernel math shuffle ;

IN: sequences.extras

: find-pred-loop
    ( ... i n seq quot: ( ... elt -- ... calc ? ) -- ... calc/f i/f elt/f )
    2pick < [
        [ nipd call ] 4keep 3 7 0 nrotated
        [ [ 3drop ] 2dip rot ]
        [ 2drop [ 1 + ] 3dip find-pred-loop ] if
    ] [ 4drop f f f ] if ; inline recursive