From: Robert Dober Date: 2006-07-06T19:36:05+09:00 Subject: [Bug?] Confused exception handling in Continuation Context ------=_Part_70000_24123551.1152182162286 Content-Type: multipart/alternative; boundary="----=_Part_70001_6333120.1152182162286" ------=_Part_70001_6333120.1152182162286 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Hi all I just went over some old Iterator code from the talk-list when I found some very strange behavior concerning Exception when using the iterator. The below code loops inside the rescue clause, as a matter of fact it loops between puts i.next and puts "No more dudes" I did not find any open bug report similar to it. I tried to isolate the behavior but could not reproduce it without the callcc stuff. I tested this with * ruby 1.8.4 (2005-12-24) [i386-cygwin] * ruby 1.8.4 (2005-12-24) [i686-linux] * ruby 1.9.0 (2006-04-21) [i486-linux] -------------------------------------------- 8< ------------------------------------------------------------------- class Iterator class Exhausted < Exception; end def initialize( enum ) @enum = enum @next = nil end def next return @next.call if @next @enum.each do |item| callcc{ |@next| return item } end # do raise Exception end # def next def reset @next = nil end end # class Iterator i = Iterator.new( %w{ Ringo John Paul George } ) begin loop do puts i.next end rescue Exception puts "No more dudes" end #i.reset puts i.next --------------------------------------------------->8-------------------------------------------- Cheers Robert ------=_Part_70001_6333120.1152182162286 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline
Hi all

I just went over some old Iterator code from the talk-list when I found some very strange behavior concerning Exception when
using the iterator.

The below code loops inside the rescue clause, as a matter of fact it loops between
      puts i.next
and
     puts "No more dudes"

I did not find any open bug report similar to it.

I tried to isolate the behavior but could not reproduce it without the callcc stuff.
I tested this with
* ruby 1.8.4 (2005-12-24) [i386-cygwin]
* ruby 1.8.4 (2005-12-24) [i686-linux]
* ruby 1.9.0 (2006-04-21) [i486-linux]

-------------------------------------------- 8< -------------------------------------------------------------------

class Iterator
        class Exhausted < Exception; end
        def initialize( enum )
                @enum = enum
                @next = nil
        end

        def next
                return @ next.call if @next
                @enum.each do
                        |item|
                        callcc{ |@next|
                                return item
                        }
                end # do
                raise Exception
        end # def next

        def reset
                @next = nil
        end
end # class Iterator

i = Iterator.new( %w{ Ringo John Paul George } )
begin
        loop do
                puts i.next
        end
rescue Exception
        puts "No more dudes"
end
#i.reset
puts i.next
--------------------------------------------------->8--------------------------------------------

Cheers
Robert
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