What should I use instead of Generator in 1.9?

Ruby
1

Hi,

I have been using Generator in 1.8, and now I need to port that code to
1.9. My code looks essentially like the code below. I’m confused as to
what the correct option is in 1.9: Fibers? Enumerator?
Enumerator::generator? I’d like to know the simplest most
straightforward option possible, since I’m still a relatively novice
Ruby practitioner.

Any help gratefully received!

require ‘generator’

def bar
Generator.new do |g|
(1…10).each do |number|
g.yield number
end
end
end

@foo = bar

while true
if @foo.next?
if (number = @foo.next)
puts number.to_s
end
else
exit
end
end

2

Hi,

An Enumerator is the right choice.

However, in your case you don’t even need to explicitly create an
Enumerator, because this will be done automatically when omitting the
block for the “each” method:

@foo = (1…10).each

Most “each” methods work like that.

3

Thanks!! How do I implement the equivalent of generator’s .next? method
in order to avoid the following…

irb(main):001:0> @foo = (1…10).each
=> #<Enumerator: 1…10:each>
irb(main):002:0> while true
irb(main):003:1> puts @foo.next
irb(main):004:1> end
1
2
3
4
5
6
7
8
9
10
StopIteration: iteration reached an end
from (irb):3:in next' from (irb):3 from /usr/local/bin/irb:12:in’
irb(main):005:0>

4

On Sun, Aug 12, 2012 at 11:25 PM, Andrew S. [email protected]
wrote:

Thanks!! How do I implement the equivalent of generator’s .next? method
in order to avoid the following…

irb(main):001:0> @foo = (1…10).each
=> #<Enumerator: 1…10:each>
irb(main):002:0> while true
irb(main):003:1> puts @foo.next
irb(main):004:1> end
[snip]
StopIteration: iteration reached an end

Well, you could just do this:

begin
while true
puts @foo.next
end
rescue StopIteration
end

or even better (because loop catches the StopIteration for you):

loop do
puts @foo.next
end

Regards,
Sean

5

Hi,

Why do you you even want an external iterator? Because what you’ve wrote
down is an internal iterator created from an external iterator created
from an internal iterator (which is a lot of useless code).

6

Thanks to all!