Set::NestedGroups - grouped data eg ACL's, city/state/country etc

       Alan R. Barclay, gorilla@elaine.drink.com

new()
           creates a new Set::NestedGroups object.

       new( fh )
           creates  a  new  Set::NestedGroups  object,  the object will be initialized using data read from this
           handle. For details on the format, see the save() method

       new( $sth )
           creates a new Set::NestedGroups object, the object will be initialized using  data  read  using  this
           this DBI statement handle.  For details on the format, see the save() method

       Set::NestedGroups gives an implementation of nested groups, access control lists (ACLs) would be one
       example of nested groups.

       For example, if Joe is a Manager, and Managers have access to payroll, you can create an ACL which
       implements these rules, then ask the ACL if Joe has access to payroll.

       Another example, you may wish to track which city, state and country people are in, by adding people to
       cities, cities to states, and states to countries.

       add ( $member, $group)
           adds a member to a group. The group will be created if it doesn't already exist.

       remove ( $member, $group )
           removes  a  member  from  a  group. If this was the last member in this group, then the group will be
           deleted. If the member was only in this group, then the member will be deleted.

       save(FILEHANDLE)
           Outputs the object to the given filehandle, which must be already open in write mode.

           The format is compatible with the format used by CGI, and can be used with new to  initialize  a  new
           object;

           Returns  true  if  successfully  wrote the data, or false if something went wrong (usually that meant
           that the handle wasn't already open in write mode).

       save($sth)
           Saves the object to a DBI database. This can be used with new to initialize a new  object.  The  $sth
           should be expecting 2 values, in this fashion:

             $sth = $dbh->prepare('insert into acl values (?,?)')
             $acl->save($dbh);
             $sth->finish();

             $sth = $dbh->prepare('select * from acl');
             $newacl=new ACL($sth);

           Returns true if successfully wrote the data, or false if something went wrong.

       member ( $member, $group )
           Returns true if $member is a member of $group.

       member ( $member )
           returns true if $member exists in any group.

       group ( $group )
           returns true if $group exists

       groups ( $member, %options )
           Returns the groups that $member belongs to. Options are explained below.

       members ( $group , %options )
           Returns the members of $group. Keep on reading for the options

       list(%options)
           Returns  a  Set::NestedGroups::Member  object  that will output an list of the members & groups. This
           could be considered a calling of groups() on each member, except this is more efficient.

           The object can be used as follows.

             $list=$nested->list();
             for(my $i=0;$i<$list->rows();$i++){
               my ($member,$group)=$list->next();
               print "$member=$group\n";
             }

   options
       By default, the above methods give every valid combination. However  you  might  not  always  want  that.
       Therefore there are options which can prevent return of certain values.

       All  of  these  examples  presume  that  'joe'  is  a member of 'managers', and 'managers' is a member of
       payroll, and that you are using only one of these options. You can use all 3, but that  gets  complicated
       to explain.

       -norecurse=>1

       No Recursion is performed, method would ignore payroll, and return only managers.

       -nomiddles=>1

       Doesn't returns groups 'in the middle', method would ignore mangers, and return only payroll.

       -nogroups=>1

       Doesn't  return  members  that  are groups. This only applies to the list() method, in which case it acts
       like nomiddles, except on the member instead of the group. list would ignore managers and return  joe  =>
       managers , joe => payroll.

       This sounds a lot more confusing than it actually is, once you try it once or twice you'll get the idea.

       Set::NestedGroups - grouped data eg ACL's, city/state/country etc

       Hey! Theabovedocumenthadsomecodingerrors,whichareexplainedbelow:

       Around line 276:
           You forgot a '=back' before '=head1'

       Around line 278:
           '=item' outside of any '=over'

       Around line 350:
           You forgot a '=back' before '=head2'

       Around line 378:
           =back doesn't take any parameters, but you said =back 2

           =back without =over

perl v5.36.0                                       2022-10-15                                  NestedGroups(3pm)

perl(1), CGI, DBI.

         use Set::NestedGroups;
         $nested = new Set::NestedGroups;
         $nested->add('user','group');
         $nested->add('group','parentgroup');
         do_something() if($nested->member('user','parentgroup'));