ruby - Check if a constant is already defined

Question

This is a simple one, I hope. How do I check, in the following example, if a constant is already defined?

#this works
var = var||1
puts var
var = var||2
puts var

#this doesn't
CONST = CONST||1
puts CONST
CONST = CONST||2
puts CONST

=> 1
   1
   uninitialized constant CONST (NameError)

Answer 1

CONST = 2 unless defined? CONST

See here for more about awesome defined? operator.

^{P.S. And in the future I guess you'll want var ||= 1 instead of var = var||1.}