1.coroutine
Translation:
routine例程
coroutine協程
subroutine子例程
Concept:
allowing multiple entry points for suspending and resuming execution at certain locations
Naming from:
coroutine (cooperative routine), for implementing cooperative tasks
Coroutine
http://en.wikipedia.org/wiki/Coroutine
Revisiting Coroutines
http://www.inf.puc-rio.br/~roberto/docs/MCC15-04.pdf
協程
http://zh.wikipedia.org/wiki/%E5%8D%8F%E7%A8%8B
2.Comparison with subroutines
“Subroutines are special cases of … coroutines.” –Donald Knuth.
子例程只有一個入口點且只返回一次且返回到其調用者，而協程允許多個入口點且可以跳出多次且不一定返回到調用者
3.Implementation
Coroutines are best implemented using continuations.
4.協程與用戶態線程的區別
協程的真正意義在於例程的調出調入。用於實現協作式的例程切換。這種例程可用於與異步機制配合解決阻塞調用問題。
協程只是負責用戶態線程實現當中的線程切換的實現。
用戶態線程不一定用到協程，任務隊列+線程/線程池也是用戶態線程，只是不能切換，比如scala的actor
另外，erlang的輕量機進程是虛擬機實現的
用戶線程也不一定都是協作式調度策略，比如erlang的輪轉調度策略，go 1.2後具有簡單搶佔機制的調度策略
5.coroutine的分類
對稱（ symmetric）協程
var q := new queue
coroutine produce
loop
while q is not full
create some new items
add the items to q
switch to consume
coroutine consume
loop
while q is not empty
remove some items from q
use the items
switch to produce非對稱協程（ asymmetric coroutines）
var q := new queue
generator produce
loop
while q is not full
create some new items
add the items to q
yield consume
generator consume
loop
while q is not empty
remove some items from q
use the items
yield produce
subroutine dispatcher
var d := new dictionary(generator → iterator)
d[produce] := start produce
d[consume] := start consume
var current := produce
loop
current := next d[current]
6.common use
implementing more familiar program components such as cooperative tasks, exceptions, event loop, iterators, infinite lists and pipes.
State machines within a single subroutine
Actor model of concurrency
Generators
Communicating sequential processes
Producer / consumer patterns
Multiplexed I/O
7.Languages with native support
F# Ruby Pascal Go Scheme Haskell Perl C# PHP Javascript Tcl Python Stackless_python Lua Rubby Simula Cilkplus
Erlang
9. C/C++的coroutine
參看http://blog.csdn.net/cadem/article/details/48653553
10.Java coroutine
10.1. kilim
11.Lua的coroutine
Lua語言實現的協程是一種非對稱式 (asymmetric)協程，或稱半對稱式(semi-symmetric)協程，又或乾脆就叫半協程(semi-coroutine)。
12.Python的coroutine
Greenlet – python下著名的協程庫
gevent – using greenlet 的併發模型/網絡庫
eventlet 基於greenlet的併發模型/網絡庫
Stackless python
Greenlet
