Put simply, a DLF converter is a perl object which implements a set of predefined methods (aka an “interface” in the object-oriented jargon).
Since a DLF converter is a perl object, it must be
          instantiated from a class. Classes in perl are defined in
          packages. We'll name the package which implements our
          converter
          MyConverters::SyslogCommonConverter.
          To create such a package, you need to create a file named
          MyConverters/SyslogCommonConverter.pm
          in a directory searched by perl.
          
You can obtain perl's default search list by running
                  the command $ perl
                  -V
This search list can be modified by setting the
                  PERL5LIB environment variables.
                
Here is a first cut of our DLF converter:
package MyConverters::SyslogCommonConverter;
use base qw/Lire::DlfConverter/;
1;
          
          
          The first line declare that the code is in the
          MyConvertersw::SyslogCommonConverter
          package. The second one specifies that objects in this
          package are subclasses of the
          Lire::DlfConverter packages.
          The last line fullfill perl's requirement that package
          returns a true value once they are initialized.
        
This is a complete DLF, altough useless, DLF Converter. In fact, it isn't complete because if you tried to register an instance of that class, you'll get “unimplemented method” errors. Besides, we don't even yet have a formal way to create instance of our converter. This is our next task.