F# and PLINQ extension methods

Question

While digging deeper into the latest release of F# I tried to have it interacting with PLINQ. I've noticed, however, that the two don't play very nice together code-wise. In fact it didn't seem possible to write code such as the following:

open System.Linq
let someArray = [|"abc"; "def"|]
someArray.AsParallel().Count(new Func<_,_>(fun s -> s.Length = 3))

because the extension methods for ParallelQuery contained in the System.Linq.ParallelEnumerable class didn't seem to get picked up by F#.
I wouldn't be surprised if there were no support for extension methods at all, but since I can access the someArray.Count extension method defined for IEnumerable I wonder why can't I access those of PLINQ.
Am I missing something?
Is this an F# limitation? If so, is it by desing? If not, will it be addressed in a future release?

Answer 1

If you're not yet using .NET 4.0, you can write that as:

#r "System.Threading"
open System.Linq

let someArray = [|"abc"; "def"|]

someArray.AsParallel<string>()
|> Seq.filter (fun s -> s.Length = 3)
|> Seq.length

Come .NET 4.0, you can just write:

let someArray = [|"abc"; "def"|]

someArray
|> Array.Parallel.filter (fun s -> s.Length = 3)
|> Array.length

F# prefers the use of the Seq module over Linq extension methods. There are some helper functions available, however, in the FSharp.PowerPack.Linq assembly.