REGEX WITH WILDCARD DELIMITER
41 seconds, 1,000,000 iterations

my @nums;
push @nums, pos() - 1 while m/-[^-]/g;
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REGEX WITH SPACE DELIMITER
16 seconds, 1,000,000 iterations

my @nums;
push @nums, pos() - 1 while m/- /g;
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SUBSTR WITH SPACE DELIMITER
13 seconds, 1,000,000 iterations

my (@nums, $pos);
push @nums, $pos while $pos = index($_, '- ', $pos) + 1;
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Note that all of the above have to have a space added to the end beforehand, and also removed afterwards if you intend to use the line for anything else:

$_ = '   ----------  -------------------------  --------  ----  ------
+-------------------  -----  ----  -----------  -----------';
$_ .= ' ';
my (@nums, $pos);
push @nums, $pos while $pos = index($_, '- ', $pos) + 1;
print join(' ', @nums);
chop;
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