20. データ構造 type Json = | JNull | JBool of bool | JNumber of float | JString of string | JList of Json list | JObject of Map<string, Json> 21. 用意したデータ構造に変換 // この発表ではFParsecというライブラリを使います let jnull = pstring "null" >>% JNull let jtrue = pstring "true" >>% (JBool true) let jfalse = pstring "false" >>% (JBool false) let jnumber = pfloat |>> JNumber let str = manyChars (noneOf """) |> between (pchar '"')