#!/usr/bin/perl -l

use strict;
use warnings;
use String::Sprintf;

my $formatter = String::Sprintf->formatter(
  F => sub {
    my($width, $value, $values, $letter) = @_;
    my $s = sprintf "%${'width'}f", $value;
    $s =~ s/\.?0*$//;
    return $s;
  }
);
print $formatter->sprintf( "%u", -0.5 );