... "start of string" or "end of string" markers ... should be replaced ... with lookarounds for $sep ...

But if  $sep can be  \n (newline), then the lookarounds become the built-in  ^ $ anchors (with the  /m modifier asserted, of course), which I would expect to be significantly faster than a constructed lookaround. The
    my $concat = join $sep, '', @tokens, '';
statement building the target string becomes
    my $concat = join $sep, @tokens;
because  ^ $ always behave as expected at start/end-of-string.

Give a man a fish:  <%-{-{-{-<

In reply to Re^4: Multi-thread combining the results together by AnomalousMonk
in thread Multi-thread combining the results together by Marshall

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