From: Joel VanderWerf <joelvanderwerf@...>
Date: 2013-11-24T18:55:01-08:00
Subject: [ruby-core:58562] Re: [ruby-trunk - Feature #9145][Feedback] Queue#pop(true) return nil if empty instead of raising ThreadError

On 11/23/2013 08:30 PM, Glass_saga (Masaki Matsushita) wrote:
> I think we can't change default behavior of Queue#pop(true) because some code expects ThreadError to be raised.
> However, it may be possible to introduce new keyword argument like following:
>
> q = Queue.new
> while next_item = q.pop(true, exception: false) # it doesn't raise ThreadError and returns nil.
>    # do something
> end

Or what about a new method, Queue#pop?, which is always non-blocking and 
non-raising. It would behave like:

class Queue
   def pop?
     pop(true)
   rescue ThreadError
     nil
   end
end

q = Queue.new

q << 1
q << 2
q << 3

while x=q.pop?
   p x
end

__END__
output:
1
2
3