From: Minkoo Seo <minkoo.seo@...>
Date: 2006-02-14T16:23:26+09:00
Subject: Continuation in ruby

Hi all.

I've written the following code to learn continuations in ruby only to
fail. Please have a look at:


def print_num
    for i in (1..10)
        puts i
        if i % 2 == 0; callcc{|c| return c}; end
    end
end

cont = print_num
puts "Yae, I love even~"
cont.call
puts "Bye"


This code produces:

C:\WINDOWS\system32\cmd.exe /c ruby a.rb
1
2
Yae, I love even~
3
4
Yae, I love even~
5
6
Yae, I love even~
7
8
Yae, I love even~
9
10
Yae, I love even~
Yae, I love even~
a.rb:10: undefined method `call' for 1..10:Range (NoMethodError)
shell returned 1
Hit any key to close this window...

This is contrary to my intuition. I've called cont.call only once, and
cont.call should put the following command, put "bye", into stack. I
can't figure out the reason why cont.call is called indefinitely.

Best,
Minkoo Seo