in reply to Re: Modifying pos() from within (?{...})
in thread Modifying pos() from within (?{...})

Oops, that * in the unpack template was redundant. 

  my @chunks = unpack '( (x4L X8Lx4/a L)> )*', $input;

  while ( my ($tag, $data, $crc) = splice(@chunks, 0, 3) ) {
    ...
  }

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