my $loc = Data::Localizer->new;
$loc->add_localizer(
  Data::Localize::Gettext->new(
    formatter => Data::Localze::Format::Gettext->new(
      functions => {
        foo => sub {
          # do something and return localized text
          return ...;
        },
        bar => sub {
          ...
        }
      }
    )
  )
);

[% loc.localize( "%foo(...)" ) %][% # will call foo %]