1.9: Orcish Manouvre Sort

• Caches extracted keys in a hash
• Assignments to the hash in ||=
• Called the orchish because of Or-Cache
• Created by Joseph Hall
• It will re-extract keys for any record with a false value
• The caching hash must be cleared beforehand
  • Sort::Maker declares a caching hash in the anonymous sub
• Hash lookups are still O( N log N )
• Good for medium sort sets
• Pass 'orcish' option to make_sorter

  	sub {
  		my %or_cache ;
  
  
  		sort {
  		(
  		  ( $or_cache{$a} ||=
  			do{ my ($val) = map { $_->[0] } $a ; $val } )
  				cmp
  		  ( $or_cache{$b} ||=
  			do{ my ($val) = map { $_->[0] } $b ; $val } )
  		)
  			||
  		(
  		  ( $or_cache{$a} ||=
  			do{ my ($val) = map { $_->[1] } $a ; $val } )
  				cmp
  		  ( $or_cache{$b} ||=
  			do{ my ($val) = map { $_->[1] } $b ; $val } )
  		)
  
  		} @_  ;
  	}