作者：Ryan Connelly

示例

> say insert-at('alfa', <a b c d>, 2);
a alfa b c d

源代码：P21-topo.pl

use v6;

sub insert-at($elem, @list is copy, $place)
{
    @list.splice($place - 1, 0, $elem);

    @list
}

say "{insert-at('alfa', <a b c d>, 2)}";