You may have to fix/fudge the LAST number, but this seems to be what you want:

$_='   ----------  -------------------------  --------  ---
-  -------------------------  -----  ----  -----------  -----------'; 
while( m/-\S.\s|$/g){
  print pos() -1,qq(\n)
}
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OUTPUT:

13
40
50
56
83
90
96
109
121
[download]