import scala.io.Source
import scala.util.parsing.combinator.Parsers
import scala.util.parsing.input.Reader
import scala.util.parsing.input.Position

object DemoApp extends App {
	val parsers = new DemoParsers
	val reader = new DemoReader(10)
	val result = parsers.startsWith("s").*(reader)
	Console println result
}

class DemoReader(n: Int) extends Reader[String] {
	def atEnd = n == 0
	def first = "s" + n
	def rest = new DemoReader(n - 1)
	def pos = new Position { def line = 0; def column = 0; def lineContents = first }
}

class DemoParsers extends Parsers {
	type Elem = String
	def startsWith(prefix: String) = acceptIf(_ startsWith prefix)("Error: " + _)
}