anchor.diff:  open Fable.Arch.Html
   open Fable.Arch.RouteParser.Parsing
   open Fable.Arch.RouteParser.RouteParser
  +open Fable.Core.JsInterop
   open Fable.Import.Browser
   open System.Text.RegularExpressions
   
  
positive.code:   open Fable.Core.JsInterop
  
    let onInput x = onEvent "oninput" (fun e -> x (unbox e?target?value))
  
  type Operator =
    | Sum
    | Sub
    | Mul
    | Unknown
  
  type Model = 
    { Operator: Operator
      NumberA: int
      NumberB: int
    }
  
    static member Initial =
      {
        Operator = Unknown
        NumberA = 0
        NumberB = 0
      }
  
  type Page =
    | Index
    | Sum of int * int
    | Sub of int * int
    | Mul of int * int
  
  type Actions =
    | NavigateTo of Page
  
negative.code:   | Sum (numA, numB) -> Some (sprintf "/sum/%i/%i" numA numB)
    | Sub (numA, numB) -> Some (sprintf "/sub/%i/%i" numA numB)
    | Mul (numA, numB) -> Some (sprintf "/mul/%i/%i" numA numB)
    | Divide(numA, numB) -> Some (sprintf "/divide/%i/%i" numA numB)
    | Unknown(numA, numB) -> Some (sprintf "/unknown/%i/%i" numA numB)
  
  let mapToRoute route =
    match route with
  