package _XSprintf;
use overload '""' => sub { shift->() };
package main;
sub xsprintf {
  my $fmt =shift;
  my $bind=\@_;
  return bless sub { sprintf $fmt,@_ ? @_ : @$bind },'_XSprintf';
}

my ($char,$ord,$bits)=('A');
my $diag=xsprintf("%s : %3d => '%8s'\n",$char,$ord,$bits);
for ($char='A';length($char)==1;$char++) {
  $ord=ord $char;
  $bits=unpack 'B*',$char;
  print $diag;
}
__END__
A :  65 => '01000001'
B :  66 => '01000010'
C :  67 => '01000011'
D :  68 => '01000100'
E :  69 => '01000101'
...