From: Frisco Del Rosario <friscodelrosario@...>
Date: 2009-01-15T16:39:03+09:00
Subject: Prime.include?(1) hangs Ruby scripts and irb

Ruby version 1.8.6
Mac OS 10.5.2

I would like a Ruby script to do something if a result is a prime 
number, or do something else if the result is not prime. But Ruby is 
hanging on instance_of_Prime.includes?(some prime number). For example, 
in irb:

$ irb
>> require 'mathn'
=> true
>> foo=Prime.new
=> #<Prime:0x32bab8 @primes=[], @seed=1, @counts=[]>
>> puts foo.include?(2)
true
=> nil
>> puts foo.include?(1)

Expected:
false

Got:
Nothing, and programs won't exit.