(binary-reduce) ( seq start quot: ( elt1 elt2 -- newelt ) from length -- value )

Vocabulary

sequences.private

Inputs

seq	an object
start	an object
quot	a quotation with stack effect ( elt1 elt2 -- newelt )
from	an object
length	an object

Outputs

value

an object

Definition

USING: kernel math ;

IN: sequences.private

: (binary-reduce)
    ( seq start quot: ( elt1 elt2 -- newelt ) from length -- value )
    dup 4 < [
        integer>fixnum {
            [ 2drop nip ]
            [ 2nip swap nth-unsafe ]
            [ -rot [ drop swap nth2-unsafe ] dip call ]
            [ -rot [ drop swap nth3-unsafe ] dip bi@ ]
        } dispatch
    ] [
        [ 2/ ] [ over - ] bi [ 2dup + ] dip
        [ (binary-reduce) ] [ 2curry ] curry 2bi@ pick
        [ 3bi ] dip call
    ] if ; inline recursive