结合F#异步函数
问题描述:
我在这里有点沮丧。我知道我已经得到了所有的位,但我不知道如何把它们混合起来......结合F#异步函数
let saveImageToDisk path content =
async {
use s = new FileStream(path, FileMode.OpenOrCreate)
do! s.AsyncWrite(content)
printfn "Done writing %A" path
} // returns Async<unit>
let getImages imageUrls =
imageUrls
|> Seq.map (fun url -> topath url, getImage url)
//Next line not happy because content is Async<byte[]> instead of byte[]
|> Seq.map (fun (path, content) -> saveImageToDisk path content)
|> Async.Parallel
|> Async.RunSynchronously
答
可以使用async
表达结合两种:
let getImages imageUrls =
imageUrls
|> Seq.map (fun url -> async {
let! content = getImage url
return! saveImageToDisk (topath url) content })
|> Async.Parallel
|> Async.RunSynchronously
非常好,感谢你及时的答复! – Benjol 2011-04-17 11:56:18
基本上,由于Async是monad,所以你可以将它们两个组合成另一个Async。 :) – 2011-04-18 19:14:31