The below code fails as it errors out saying "odd number of results in anonymous hash". Now I don't see why any of this is being read as an anony hash, so I come to you monks in hope of englightenment on what the issue is and what I need to do to get around it. 
#assuming $form_string is either form_name or form_number
# assuming $param_string are key/values separated with =>
   $mech->submit_form(
    $form_string => $d,
     fields      => {
         $param_string
     });

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In reply to passing a variable as a string by coldfingertips

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