From: David Flanagan <david@...>
Date: 2007-09-12T08:05:42+09:00
Subject: autoloading Fiber

In order to use the new Fiber class in 1.9, we have to require 'fiber'. 
  The fiber functionality is actually built into the core (so it can be 
used for external iterators) but in order to get at the API for using it 
in Ruby, we have to require 'fiber'. Ko1 says that this is for safety 
reasons.  (The same goes for continuations in Ruby 1.9: you must 
explictly require them if you want to use them.)

Someone (I forget who) on this list pointed out that the Fiber class 
itself is defined by default, but that the methods of the class are not. 
  I don't understand why this is, and I've just realized that it causes 
problems with autoload:

autoload :Fiber, "fiber"

This won't work. Since Fiber is already defined, the "fiber" module will 
never be autoloaded...  (Unless ko1 thinks that fibers are so unsafe we 
should not be allowed to autoload them? :-)

Maybe I'm missing something, but I don't see any code that depends on 
the Fiber constant being defined before any of its methods are, so I'm 
wondering if the patch below wouldn't be okay.  I've barely tested it, 
but it makes autoload work and it doesn't seem to interfere with 
external iterators.

	David


$ diff -u cont.c~ cont.c
--- cont.c~     2007-08-29 22:59:14.000000000 -0700
+++ cont.c      2007-09-11 15:55:37.000000000 -0700
@@ -729,9 +729,6 @@
  void
  Init_Cont(void)
  {
-    rb_cFiber = rb_define_class("Fiber", rb_cObject);
-    rb_undef_alloc_func(rb_cFiber);
-    rb_eFiberError = rb_define_class("FiberError", rb_eStandardError);
  }

  void
@@ -748,6 +745,9 @@
  void
  Init_Fiber_body(void)
  {
+    rb_cFiber = rb_define_class("Fiber", rb_cObject);
+    rb_undef_alloc_func(rb_cFiber);
+    rb_eFiberError = rb_define_class("FiberError", rb_eStandardError);
      rb_define_singleton_method(rb_cFiber, "new", rb_fiber_s_new, 0);
      rb_define_method(rb_cFiber, "resume", rb_fiber_m_resume, -1);
      rb_define_method(rb_cFiber, "transfer", rb_fiber_m_transfer, -1);