I also wanted to abuse the regex system with twelve-level-deep s///e recursion to implement my Pentominos Solving Quine, but instead found that perl would crash horribly if it tried to recurse there.

for $pattern (@patterns)
{
    while ($data =~ m/(?=$pattern)/g)
    {
        do_recurse($data, pos($data), $pattern);
        # $data is the source
        # pos($data) is the found place in the souce
        ++pos($data);
    }
}
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The alternative method uses pos() as an lvalue and m/(?=)/g as in the loop above, to allow me to iterate through matches yet not recurse via any regex code-evaluating trick. I do recurse, but not by getting the regex to do the call.