toyJsonParser.fsx

#r @"C:\GitHub\FParsec\FParsec.1.0.2\lib\net40-client\FParsecCS.dll"
#r @"C:\GitHub\FParsec\FParsec.1.0.2\lib\net40-client\FParsec.dll"

open System
open FParsec

let print s = printfn "%A" s

type kvp = { key: String; value: int}

let quote = pchar('"')
let notQuote = noneOf(['"'])
let notQuotesTill = manyCharsTill(notQuote)
let notQuotes = notQuotesTill(quote)

let quotedParser = parse{do! spaces
                         do! skipChar('"')
                         let! listChar = notQuotes
                         do! spaces
                         return listChar }

let intParser = quotedParser |>> Convert.ToInt32

let toyJsonParser = parse {do! spaces
                           do! skipChar('{')
                           let! key = quotedParser
                           do! skipChar(':')
                           let! value = intParser
                           do! skipChar('}')
                           do! spaces
                           return({ key = key;
                             value = value })}

run toyJsonParser """
  { "age": "29" }
"""
|> function
  | Failure(err,_,_) -> print ("Fail: " + err)
  | Success(result,_,_)   ->
    printfn "KVP: %A" result
    printfn "Key: %A" result.key
    printfn "Val: %A" result.value