From: Knut.Franke@... Date: 2014-10-24T16:16:35+00:00 Subject: [ruby-core:65892] [ruby-trunk - Feature #10344] [PATCH] Implement Fiber#raise Issue #10344 has been updated by Knut Franke. Koichi Sasada wrote: > > I think [Consumer](http://nome.github.io/coroutines/Consumer.html) is an example of a semi-coroutine (in the sense that it uses Fiber.yield, not Fiber#transfer) that benefits from having Fiber#raise. > > Interesting. I don't know details of this library. Could you explain why it is important in this library? Consumer provides an abstraction for (semi-)coroutines that accept (consume) values; analogous to an Enumerator, which produces (enumerates) values. Since a consumer may need to do resource cleanup and/or produce a final result, we need some way to signal end of values. I think the most natural way to do this is to raise StopIteration in the consumer: The situation is analogous to calling Enumerator#next when no more values are available, and StopIteration terminates Kernel#loop, which often allows writing consumers very concisely. In general, I think Fiber is a powerful primitive that can be used by libraries to build abstractions like Enumerator, Consumer and others. While Enumerator does not require the #raise feature, other abstractions can very well benefit from it. ---------------------------------------- Feature #10344: [PATCH] Implement Fiber#raise https://bugs.ruby-lang.org/issues/10344#change-49634 * Author: Knut Franke * Status: Open * Priority: Normal * Assignee: * Category: * Target version: ---------------------------------------- While it is possible to implement this in pure Ruby (by wrapping Fiber.yield and Fiber#resume), this feels like a low-level feature that ought to be provided out of the box. Also, the C implementation is more straight-forward, and more efficient. Unfortunately, it is not quite possible to implement this as a C extension module (without resorting to wrappers again); cf. the change to make_passing_arg(). Example usage: ~~~ fib = Fiber.new do counter = 0 loop { counter += Fiber.yield } counter end fib.resume fib.resume 10 fib.resume 100 fib.raise StopIteration # => 110 ~~~ ---Files-------------------------------- 0001-Implement-Fiber-raise.patch (4.12 KB) 0001-Implement-Fiber-raise.patch (3.51 KB) 0001-Implement-Fiber-raise-in-ext-fiber.patch (3.6 KB) -- https://bugs.ruby-lang.org/