Use Scala parser combinator to parse CSV files

Question

I\'m trying to write a CSV parser using Scala parser combinators. The grammar is based on RFC4180. I came up with the following code. It almost works, but I cannot get it to

Answer 1

With Scala Parser Combinators library out of the Scala standard library starting from 2.11 there is no good reason not to use the much more performant Parboiled2 library. Here is a version of the CSV parser in Parboiled2's DSL:

/*  based on comments in https://github.com/sirthias/parboiled2/issues/61 */
import org.parboiled2._
case class Parboiled2CsvParser(input: ParserInput, delimeter: String) extends Parser {
  def DQUOTE = '"'
  def DELIMITER_TOKEN = rule(capture(delimeter))
  def DQUOTE2 = rule("\"\"" ~ push("\""))
  def CRLF = rule(capture("\r\n" | "\n"))
  def NON_CAPTURING_CRLF = rule("\r\n" | "\n")

  val delims = s"$delimeter\r\n" + DQUOTE
  def TXT = rule(capture(!anyOf(delims) ~ ANY))
  val WHITESPACE = CharPredicate(" \t")
  def SPACES: Rule0 = rule(oneOrMore(WHITESPACE))

  def escaped = rule(optional(SPACES) ~
    DQUOTE ~ (zeroOrMore(DELIMITER_TOKEN | TXT | CRLF | DQUOTE2) ~ DQUOTE ~
    optional(SPACES)) ~> (_.mkString("")))
  def nonEscaped = rule(zeroOrMore(TXT | capture(DQUOTE)) ~> (_.mkString("")))

  def field = rule(escaped | nonEscaped)
  def row: Rule1[Seq[String]] = rule(oneOrMore(field).separatedBy(delimeter))
  def file = rule(zeroOrMore(row).separatedBy(NON_CAPTURING_CRLF))

  def parsed() : Try[Seq[Seq[String]]] = file.run()
}