What's the opposite of chr() in Ruby?

If String#ord didn't exist in 1.9, it does in 2.0:

"A".ord #=> 65

In Ruby up to and including the 1.8 series, the following will both produce 65 (for ASCII):

puts ?A
'A'[0]

The behavior has changed in Ruby 1.9, both of the above will produce "A" instead. The correct way to do this in Ruby 1.9 is:

'A'[0].ord

Unfortunately, the ord method doesn't exist in Ruby 1.8.

Try:

'A'.unpack('c')