### main script:
die "No client data specified"
  unless %Client::Data::positions;

while (<>) {
  print decode_positions( $_, %Client::Data::positions );
};

### client/Client/Acme.pm
package Client::Data;

use vars qw(%positions);

%positions = (
 ...
);

1;

### command line
perl -MClient::ACME magicscript.pl