sub _permittedOps()
  {
    my ($this) = @_;

    # Hashes for mapping in order to avoid if-else chaining
    my (%attr_value, %high_type, %trust_level);

    # A map associating opcode sets with trust levels.
    %trust_level = (full => full_opset(),
		 	 	  strong => opset(qw/:default :filesys_read :sys_db 
				        	     :filesys_open :filesys_write :ownprocess 
				         	    :subprocess/),
		  	 	 normal => opset(qw/:default/),
		  		  weak => opset(qw/:base_core :base_mem :base_loop 
				         	 :base_io :base_orig/),
		  	 	 none => opset(qw/:base_core :base_loop/)
		   );

    # A map associating usertype attributes with positive/negative values
    # affecting the level of trust assigned to the user. 
    %attr_value = (admin => 1, consultant => -1, editor => 0, former => -2, 
		        other => -2, programmer => 2, trainee => -1);

    # Run through all of the assigned usertypes, adjusting the trust level in %high_type
    # granted the user for each particular usertype. $1, if defined will be
    # 'former', $2 will be either 'consultant', 'editor', or 'programmer'. 
    # $3, if defined, will be either 'admin' or 'trainee'.
    foreach my $type (@usertypes) { # @usertypes is defined in the real code, don't worry :) 
      if ($type =~ /^(former)?\s?(consultant|editor|programmer)\s?
	    (admin|trainee)?$/ix)	{
	  unless ($1) {
	   # Look up the appropriate usertype and attribute values.
	   $high_type{$2} += $attr_value{$2};
	   $high_type{$2} += $attr_value{$3} if $3;
	   } else { $high_type{$2} += $attr_value{$1} }
      }
       else {
	     $high_type{other} += $attr_value{other};
      }
    }
    
    # Take the maximum trust available.
    my $max = pop(@{[sort values %high_type]});

    # Return the appropriate opset.
    ($max > 1) and return $trust_level{full};
    ($max == 1) and return $trust_level{strong};
    ($max == 0) and return $trust_level{normal};
    ($max == -1) and return $trust_level{weak};
    ($max < -1) and return $trust_level{none};   
}