sub printN($)   { my $format = shift; sub { sprintf $format, @_ } }

  my %functions = (
      -power => sub { exp( $_[0] )},
      -log2  => sub { log( $_[0] )/log(2.0) },
      -loge  => sub { log( $_[0] ) },
      -log10 => sub { log( $_[0] )/log(10.0) },
      -round => sub { int($_[0] + ($_[0] <=> 0)*0.5) },
      -trunc => sub { int $_[0] },
      -f1    => printN "%.1f",
      -f2    => printN "%.2f",
      -f3    => printN "%.3f",
      -f4    => printN "%.4f",
      -f5    => printN "%.5f",
  );