# set imput record separator to end of table string
$/ = "\n\n";

my %hash;

# now we are reading data a table at a time
while(<DATA>) {
    my ( undef, $header, $data ) = split /\+\-+\+\s*/, $_;
    $header =~ s/\s*\|\s*//g;
    @data = $data =~ m/\|([^\|]+)\|/g;
    push @{$hash{$header}}, @data;
}

use Data::Dumper;
print Dumper \%hash;

__DATA__
+---------+
| formula |
+---------+
| dat1    |
| dat2    |
| dat3    |
+---------+

+---------+
| formula |
+---------+
| dat4    |
| dat5    |
| dat6    |
+---------+

+---------+
| flubber |
+---------+
| dat11   |
| dat22   |
| dat33   |
+---------+

+---------+
| dubber  |
+---------+
| dat111  |
| dat222  |
| dat333  |
+---------+

+---------+
| dubber  |
+---------+
| dat1111 |
| dat2222 |
| dat3333 |
+---------+

__END__
$VAR1 = {
          '' => [],
          'flubber' => [
                         ' dat11   ',
                         ' dat22   ',
                         ' dat33   '
                       ],
          'formula' => [
                         ' dat1    ',
                         ' dat2    ',
                         ' dat3    ',
                         ' dat4    ',
                         ' dat5    ',
                         ' dat6    '
                       ],
          'dubber' => [
                        ' dat111  ',
                        ' dat222  ',
                        ' dat333  ',
                        ' dat1111 ',
                        ' dat2222 ',
                        ' dat3333 '
                      ]
        };