/TP/TypeSafeSplit.fs

namespace StringUtil



open Microsoft.FSharp.Core.CompilerServices

open TPUtil

open TPUtil.SimpleTypeProvider

open TPUtil.StaticArgument



type TSSplit = class end

    

[<TypeProvider>]

type SplitterProvider() =

  inherit SimpleTypeProviderBase<TSSplit> begin

    NameSpace = "StringUtil",

    StaticParams = [ StaticParameter.make<int> "count" ]

  end



  override this.GenSrc args =

    let count = (args |> List.find (fun a -> a.Name = "count")).Value :?> int

    let vars = List.init count (fun i -> "s" + (string i))

    let pat = vars |> String.concat "; "

    let tpl = vars |> String.concat ", "

    "let split =\n  \

       let split' (sep: string) (str: string) =\n    \

         match str.Split([| sep |], " + (string count) + ", StringSplitOptions.None) with\n    \

         | [| " + pat + " |] -> (" + tpl + ")\n    \

         | _ -> failwith \"not match.\"\n  \

       split'"