working

#r "System.Net.Http"

open System.Net
open System.Net.Http
open FParsec
open System.IO
open Chiron

type Elem = IDUser of string | IDAs of string | Question of string * string | Exercise of string * Elem list
    with static member ToJson(e:Elem) = match e with
        | IDUser x -> Json.write "user_id" x
        | IDAs x -> Json.write "as_id" x
        | Question (d, c) -> Json.map2 (fun _ x -> x) (Json.write "description" d) (Json.write "code" c)
        | Exercise (d, qs) -> Json.map2 (fun _ x -> x) (Json.write "description" d) (Json.write "questions" qs)

//general parsers


let Run(req: HttpRequestMessage, log: TraceWriter) =
    let anyChars = manyChars (noneOf "#`")
    // question parser functions
    let code = pstring "```" >>. anyChars .>> pstring "```"
    let question = pstring "##" >>. pipe3 anyChars (code .>> spaces) (pstring "##END" .>> spaces) (fun d c _ -> Question (d,c))
    let questions = many question .>> spaces
    let exercise = pstring "#" >>. pipe2 anyChars (questions .>> pstring "#END" ) (fun d qs -> Exercise (d, qs))
    let exercises = spaces >>. many (exercise .>> spaces)

    let test p str = match run p str with
    | Success(res, _, _) -> Some res
    | Failure(_, _, _) -> None

    async {
        log.Info("start")
        // Set name to query string
        let name =
            req.GetQueryNameValuePairs()
            |> Seq.tryFind (fun q -> q.Key = "name")

        match name with
        | Some x ->
            return req.CreateResponse(HttpStatusCode.OK, "Hello " + x.Value);
        | None ->
            return req.CreateResponse(HttpStatusCode.OK, "lol")
    } |> Async.RunSynchronously