:: compress-path ( source assoc -- destination )
    [let | destination [ source assoc at ] |
        source destination = [ source ] [
            [let | destination' [ destination assoc compress-path ] |
                destination' destination = [
                    destination' source assoc set-at
                ] unless
                destination'
            ]
        ] if
    ] ;

: (compress-path') ( source-cursor -- destination-cursor )
    dup [ value>> ] [ key>> ] bi = [
        dup value>> >>key (compress-path')
        dup [ value>> ] [ key>> ] bi = [ dup value>> >>value ] unless
    ] unless

: compress-path' ( source assoc -- destination )
    >cursor swap >>key (compress-path') value>>