skinny.util.LTSV.scala Maven / Gradle / Ivy

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package skinny.util

import scala.util.parsing.combinator.RegexParsers

/**
 * LTSV Utility.
 *
 * http://ltsv.org/
 */
object LTSV {

  def parseLine(line: String, lenient: Boolean = false): Map[String, String] = {
    LTSVParser.parse(line, lenient).head
  }

  def parseLines(lines: String, lenient: Boolean = false): List[Map[String, String]] = {
    LTSVParser.parse(lines, lenient)
  }

  def dump(value: Map[String, String]): String = dump(value.toSeq: _*)

  def dump(value: (String, String)*): String = value.map { case (k, v) => k + ":" + v }.mkString("\t")

  def dump(values: List[Map[String, String]]): List[String] = values.map(dump)

}

/**
 * LTSV Parser configuration.
 *
 * @param lenient Allow a wider range of characters in field values than the LTSV spec
 */
case class LTSVParserConfig(lenient: Boolean = false)

/**
 * LTSV Parser.
 */
class LTSVParser(config: LTSVParserConfig) extends RegexParsers {

  /*
;; ABNF 

ltsv = *(record NL) [record]
record = [field *(TAB field)]
field = label ":" field-value
label = 1*lbyte
field-value = *fbyte

TAB = %x09
NL = [%x0D] %x0A
lbyte = %x30-39 / %x41-5A / %x61-7A / "_" / "." / "-" ;; [0-9A-Za-z_.-]
fbyte = %x01-08 / %x0B / %x0C / %x0E-FF
*/

  override def skipWhitespace = false

  def ltsv = repsep(record, nl)
  def record = repsep(field, tab) ^^ { _.toMap }
  def field = label ~ ":" ~ fieldValue ^^ { case k ~ ":" ~ v => (k, v) }
  def label = {
    if (config.lenient) """[^\t\r\n:]*""".r
    else "[0-9A-Za-z_\\.-]+".r
  }
  def fieldValue = {
    if (config.lenient) """[^\t\r\n]*""".r
    else """[\u000B\u000C\u0001-\u0008\u000E-\u00FF]*""".r
  }
  def tab = '\t'
  def nl = opt('\r') <~ '\n'

  def parse(input: String): List[Map[String, String]] = parseAll(ltsv, input).getOrElse {
    throw new IllegalArgumentException("Failed to parse ltsv: " +
      (if (input.size > 1000) "\"" + input.take(1000) + "..." + "\"" else "\"" + input + "\""))
  }

}

object LTSVParser {

  def parse(input: String, lenient: Boolean = false): List[Map[String, String]] = {
    new LTSVParser(LTSVParserConfig(lenient)).parse(input)
  }

}