F＃无法解决异步功能

Question

I'm really F# noob and I tried to code very simple program which iterate list in parallel. Here is simplified code

let test = ["xx"; "yy"; "zz"]
let urls = 
    ["http://google.com";"http://google.com"]

let p l = async {
    let t = test
    for k in t do
        printf "%s" k
} 

let find = 
    urls
    |> List.map p
    |> Async.Parallel 
    |> Async.RunSynchronously
    |> ignore


[<EntryPoint>]
let main argv = 
   find  
   printfn "%A" argv
   0 // return an integer exit code

Unfortunately this program never finish. It can't solve this line:

    let t = test

It never get over that line. But if I change find and main function in this way:

let find = 
    urls
    |> List.map p
    |> Async.Parallel 

[<EntryPoint>]
let main argv = 
   find 
   |> Async.RunSynchronously
   |> ignore
   printfn "%A" argv
   0 // return an integer exit code

Everything works fine as expected. Can somebody explain me the difference please?

Also if I do not call test function but rather code list into "p" function

let t = ["xx"; "yy"; "zz"]

It works fine in first version.

Answer 1

So the problem is that find is not a function, but a value. As a result find actually runs before main (in the first example).

Changing the definition to let find() seems to work fine for me.