Such cross-like operations are common enough that there is also a cross meta-operator in Perl 6 to trick an ordinary binary operator into doing it. So instead of saying:

    my @combined = (@urls X @ids).map: {$^a ~ $^b};
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you can just say

    my @combined = @urls X~ @ids;
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That is, just put X in front of the ordinary operator to make it a cross operator.

Update: changed old X~X form to new X~ form.