From: Jeff Schwab <jeff@...>
Date: 2009-02-21T01:29:40+09:00
Subject: difference between {} and do/end

I'm coming back to Ruby after a couple years away, and finding I've 
forgotten some of the basics.  What's the difference between { ... } 
blocks and do ... end blocks?  In particular, why does one of the 
following work, while the other fails?

'%61lice'.gsub! /%(\d+)/ do $1.to_i(16).chr end # => "alice"
'%61lice'.gsub! /%(\d+)/ {  $1.to_i(16).chr   } # => SyntaxError