India's Cloud Infrastructure Leaps Ahead with Seamless Multi-Proc Support

&blk in a parameter list turns a block into a Proc; &proc at a call turns a Proc back into a block. A block is the { ... } or do ... end you attach to a method call. It is not a value you can hold by itself. You can't store a block in a variable — Ruby won't even parse it: b = { |x| x * 2 } # Syntax