$form_def = [

            {
              NAME    => 'form entry name',
              TYPE    => 'entry type = string|bool|combo|button',
              VALUE   => 'visible value',
              DATA    => 'actual data, sometimes equal to value',
              RE      => 'regexp to check input',
              RE_HELP => 'help hint text when RE fails',
              IN_CB   => 'input data filter callback',
            },

            ];