@t = ( {'b','1','w','10'},{'b','3','w','30'},{'b','2','w','40'});
foreach $f1 (@t){
  foreach $f2 (keys %$f1){
    print $$f1{$f2},"\n";
  }
}

@bb = sort func @t;

sub func{
  print ${$a}{'b'}," ",${$a}{'w'}," :";
  print ${$b}{'b'}," ",${$b}{'w'}," \n";
  print "xxx",(${$a}{'b'} lt ${$b}{'b'}),"xxx";  
  print "\n================\n";
  return ${$a}{'b'} lt ${$b}{'b'};  
}

foreach $f1 (@bb){
  foreach $f2 (keys %$f1){
    print $$f1{$f2},"\n";
  }
}