find-last-integer ( ... n quot: ( ... i -- ... ? ) -- ... i/f )

Vocabulary

math

Inputs

n	an integer
quot	a quotation with stack effect ( ... i -- ... ? )

Outputs

i/f	an integer or f

Word description

Applies the quotation to each integer from n down to 0, inclusive. Iteration stops when the quotation outputs a true value or 0 is reached. If the quotation yields a true value for some integer, the word outputs that integer. Otherwise, the word outputs f.

Notes

This word is used to implement find-last.

Definition

USING: kernel ;

IN: math

: find-last-integer
    ( ... n quot: ( ... i -- ... ? ) -- ... i/f )
    over 0 <
    [ 2drop f ] [
        [ call ] 2keep rot
        [ drop ] [ [ 1 - ] dip find-last-integer ] if
    ] if ; inline recursive