ping
On Thu, Aug 31, 2017 at 11:22 AM, Ramón García <ramon.garci...@gmail.com> wrote: > (repeated, forgot to reply to mailing list) > > Xi Ruoyao misses completely the point! > > The amount of error prone boilerplate code, that the programmer would > have to write, is huge. See examples in the excellent presentation > "C++ coroutines: a negative overhead abstraction" > https://www.slideshare.net/SergeyPlatonov/gor-nishanov-c-coroutines-a-negative-overhead-abstraction > Video: https://www.youtube.com/watch?v=_fu0gx-xseY > > What one can have with a coroutine library, are stackfull coroutines. > But they are not really useful. Not very scalable. The simplification > of programming has a high cost. > > With stackless coroutines, one can combine the simplicity of > sequential programming, with the scalability and efficiency of > asynchronous programming. > > Did you ever read Linux kernel code? There is a lot of hand written > code that tries to achieve a sequence of actions using chained > callbacks: > > void A() > { > a1(); > when event E1 happens, run B > } > > void B() > { > b1(); > when event E2 happends, run C > } > > void C() > { > c1() > } > > with Coroutines TS this is turned into > > void A() > { > a1(); > co_await E1; > b1(); > co_await E2; > c1(); > } > > but have the same efficiency and scalability of asynchronous code. > > On Sat, Aug 19, 2017 at 5:49 PM, Jonathan Wakely <jwakely....@gmail.com> > wrote: >> See the thread on gcc-help: >> https://gcc.gnu.org/ml/gcc-help/2017-08/msg00045.html >> >> >> >> On 19 August 2017 at 14:09, Ramón García <ramon.garci...@gmail.com> wrote: >>> ping. >>> >>> On Tue, Aug 15, 2017 at 2:21 PM, Ramón García <ramon.garci...@gmail.com> >>> wrote: >>>> Hello, >>>> >>>> Please consider supporting the Coroutines TS in GNU C++. >>>> >>>> It is really important to make asynchronous programming usable. >>>> >>>> Modern programs should be scalable to use the performance of multicore >>>> processors. Stackless coroutines allow the programmer to scale to >>>> millions of asynchronous requests. But without the primitives in the >>>> Concurrency TS, chaining the result of an asynchronous computation to >>>> the next step, one must program a chain of callbacks. It becomes >>>> quickly unusable. >>>> >>>> The promise/future, as specified in the concurrency TS, (that is, with >>>> the function future::then for chaining a callback to the completion of >>>> the future) make asynchronous programming somewhat more usable. >>>> Unfortunately, almost no C++ library shipped supports future with >>>> then. >>>> >>>> This is an excellent explanation of the Coroutines TS: >>>> >>>> https://www.slideshare.net/SergeyPlatonov/gor-nishanov-c-coroutines-a-negative-overhead-abstraction >>>> >>>> Both Visual C++ 2017 and CLANG (SVN version) support the Coroutines >>>> TS. Please consider it. >>>> >>>> I saw that someone started an attempt at implementing it: >>>> https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00435.html but there >>>> were no replies.
