v.nainar wrote:
> I may be missing something obvious . Why  is the '<=>' operator not
> called  when there is no block supplied to sort ?.The Pickaxe book

see:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/123637

there are optimisations in the core classes such as String which also currently affect user-defined subclasses. you can make sure that your own own <=> operator is called by using:

something.sort { | i, j | i <=> j }

instead of

something.sort

alex