of fiber body receive first yield values.
e.g.: Fiber.new{|x| p x}.yield(:ok) #=> :ok
* cont.c: rename rb_context_t#retval to rb_context_t#value.
* test/ruby/test_fiber.rb: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12425 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Fiber is known as "Micro Thread", "Coroutine", and other terms.
At this time, only Fiber#pass is supported to change context.
I want to know more suitable method name/API for Fiber (... do you
know more suitable class name instead of Fiber?) as "suspend/resume",
"call", "yield", "start/kick/stop/restart", ....
* eval.c, eval_intern.h, thread.c, yarvcore.c, yarvcore.h: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12395 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
