module Reader

open System
open System.IO

type Reader(path: string, reader: TextReader) =
    class
        let mutable line = 1

        member this.Fail(s) =
            failwith(sprintf "%s:%d: %s" path line s)

        member this.Peek() =
            reader.Peek()

        member this.Read() =
            if reader.Peek() = int '\n' then
                line <- line + 1
            reader.Read()

        member this.ReadLine() =
            line <- line + 1
            reader.ReadLine()

        member this.WhiteSpace =
            while Char.IsWhiteSpace(char(this.Peek())) do
                this.Read() |> ignore
    end