#!/usr/bin/env raku

multi combine (@a, $b) { 
    [|@a,  [@a[0][0],$b]] 
}


# the non-itemized array here will match the "regular" @a signature
multi combine (@a is item, $b) {
    [@a, [@a[0], $b]]
}

# $[] means that the signature with `@a is item` will match 
multi combine ($a, $b) { 
    $[$a, $b]
}

(reduce &combine, 1..5).raku.say;