continuations | 易学教程

How do I enable continuations in Scala?

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问题 Question says it all. (Yet, the details of how to get access to the shift and reset operations has changed over the years. Old blog entries and Stack Overflow answers may have out of date information.) See also What are Scala continuations and why use them? which talks about what you might want to do with shift and reset once you have them. 回答1: Scala 2.11 The easiest way is to use sbt: scalaVersion := "2.11.6" autoCompilerPlugins := true addCompilerPlugin( "org.scala-lang.plugins" % "scala

call-with-current-continuation - state saving concept

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问题 After reading The Seasoned Schemer I felt I understood call/cc properly. But, after seeing some WOW tricks with call/cc I found I was wrong. (define cc 0) (define (f) (call/cc (lambda (k) (set! cc k) 3))) (+ 1 2 4 (f)) ; eval's to 10 (cc 13) ; eval's to 20 That perfectly match my understanding. I think when I reach a call/cc call I am just saving the program state. and calling the function next to it with a function. If that function ( k ) is called from somewhere than I just replacing the

Is Async await keyword equivalent to a ContinueWith lambda?

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Could someone please be kind enough to confirm if I have understood the Async await keyword correctly? (Using version 3 of the CTP) Thus far I have worked out that inserting the await keyword prior to a method call essentially does 2 things, A. It creates an immediate return and B. It creates a "continuation" that is invoked upon the completion of the async method invocation. In any case the continuation is the remainder of the code block for the method. So what I am wondering is, are these two bits of code technically equivalent, and if so, does this basically mean that the await keyword is

C# 5 Async/Await - is it concurrent?

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问题 I've been considering the new async stuff in C# 5, and one particular question came up. I understand that the await keyword is a neat compiler trick/syntactic sugar to implement continuation passing, where the remainder of the method is broken up into Task objects and queued-up to be run in order, but where control is returned to the calling method. My problem is that I've heard that currently this is all on a single thread. Does this mean that this async stuff is really just a way of turning

What are Scala continuations and why use them?

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问题 I just finished Programming in Scala , and I\'ve been looking into the changes between Scala 2.7 and 2.8. The one that seems to be the most important is the continuations plugin, but I don\'t understand what it\'s useful for or how it works. I\'ve seen that it\'s good for asynchronous I/O, but I haven\'t been able to find out why. Some of the more popular resources on the subject are these: Delimited continuations and Scala Goto in Scala A Taste of 2.8: Continuations Delimited Continuations

Implementing yield (yield return) using Scala continuations

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问题 How might one implement C# yield return using Scala continuations? I\'d like to be able to write Scala Iterator s in the same style. A stab is in the comments on this Scala news post, but it doesn\'t work (tried using the Scala 2.8.0 beta). Answers in a related question suggest this is possible, but although I\'ve been playing with delimited continuations for a while, I can\'t seem to exactly wrap my head around how to do this. 回答1: Before we introduce continuations we need to build some

What's the difference between a continuation and a callback?

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问题 I\'ve been browsing all over the web in search of enlightenment about continuations, and it\'s mind boggling how the simplest of explanations can so utterly confound a JavaScript programmer like myself. This is especially true when most articles explain continuations with code in Scheme or use monads. Now that I finally think I\'ve understood the essence of continuations I wanted to know whether what I do know is actually the truth. If what I think is true is not actually true, then it\'s

Is Async await keyword equivalent to a ContinueWith lambda?

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问题 Could someone please be kind enough to confirm if I have understood the Async await keyword correctly? (Using version 3 of the CTP) Thus far I have worked out that inserting the await keyword prior to a method call essentially does 2 things, A. It creates an immediate return and B. It creates a \"continuation\" that is invoked upon the completion of the async method invocation. In any case the continuation is the remainder of the code block for the method. So what I am wondering is, are these