Scala example source code file (Arguments.scala)

This example Scala source code file (Arguments.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

arguments, array, boolean, char, collection, option, parser, string, string*, tuple2, unit

The Arguments.scala Scala example source code

/*     ___ ____ ___   __   ___   ___
**    / _// __// _ | / /  / _ | / _ \  Scala classfile decoder
**  __\ \/ /__/ __ |/ /__/ __ |/ ___/  (c) 2003-2013, LAMP/EPFL
** /____/\___/_/ |_/____/_/ |_/_/      http://scala-lang.org/
**
*/


package scala.tools.scalap

import scala.collection.mutable
import mutable.{ Buffer, ListBuffer }

object Arguments {
  case class Parser(optionPrefix: Char) {
    val options: mutable.Set[String]                = new mutable.HashSet
    val prefixes: mutable.Set[String]               = new mutable.HashSet
    val optionalArgs: mutable.Set[String]           = new mutable.HashSet
    val prefixedBindings: mutable.Map[String, Char] = new mutable.HashMap
    val optionalBindings: mutable.Map[String, Char] = new mutable.HashMap

    def argumentError(message: String): Unit = Console.println(message)

    def withOption(option: String): Parser = {
      options += option
      this
    }

    def withOptionalArg(option: String): Parser = {
      optionalArgs += option
      this
    }

    def withOptionalBinding(option: String, separator: Char): Parser = {
      optionalBindings(option) = separator
      this
    }

    def withPrefixedArg(prefix: String): Parser = {
      prefixes += prefix
      this
    }

    def withPrefixedBinding(prefix: String, separator: Char): Parser = {
      prefixedBindings(prefix) = separator
      this
    }

    def parseBinding(str: String, separator: Char): (String, String) = (str indexOf separator) match {
      case -1   => argumentError("missing '" + separator + "' in binding '" + str + "'") ; ("", "")
      case idx  => ((str take idx).trim, (str drop (idx + 1)).trim)
    }

    def parse(args: Array[String]): Arguments = {
      val res = new Arguments
      parse(args, res)
      res
    }

    def parse(args: Array[String], res: Arguments) {
      if (args != null) {
        var i = 0
        while (i < args.length)
          if ((args(i) == null) || (args(i).length() == 0))
            i += 1
          else if (args(i).charAt(0) != optionPrefix) {
            res.addOther(args(i))
            i += 1
          } else if (options(args(i))) {
            res.addOption(args(i))
            i += 1
          } else if (optionalArgs contains args(i)) {
            if ((i + 1) == args.length) {
              argumentError("missing argument for '" + args(i) + "'")
              i += 1
            } else {
              res.addArgument(args(i), args(i + 1))
              i += 2
            }
          } else if (optionalBindings contains args(i)) {
            if ((i + 1) == args.length) {
              argumentError("missing argument for '" + args(i) + "'")
              i += 1
            } else {
              res.addBinding(args(i),
                parseBinding(args(i + 1), optionalBindings(args(i))));
              i += 2
            }
          } else {
            val iter = prefixes.iterator
            val j = i
            while ((i == j) && iter.hasNext) {
              val prefix = iter.next
              if (args(i) startsWith prefix) {
                res.addPrefixed(prefix, args(i).substring(prefix.length()).trim());
                i += 1
              }
            }
            if (i == j) {
              val iter = prefixedBindings.keysIterator;
              while ((i == j) && iter.hasNext) {
                val prefix = iter.next
                if (args(i) startsWith prefix) {
                  val arg = args(i).substring(prefix.length()).trim()
                  i = i + 1
                  res.addBinding(prefix,
                    parseBinding(arg, prefixedBindings(prefix)));
                }
              }
              if (i == j) {
                argumentError("unknown option '" + args(i) + "'")
                i = i + 1
              }
            }
          }
      }
    }
  }

  def parse(options: String*)(args: Array[String]): Arguments = {
    val parser = new Parser('-')
    options foreach (parser withOption _)
    parser parse args
  }
}

class Arguments {
  private val options   = new mutable.HashSet[String]
  private val arguments = new mutable.HashMap[String, String]
  private val prefixes  = new mutable.HashMap[String, mutable.HashSet[String]]
  private val bindings  = new mutable.HashMap[String, mutable.HashMap[String, String]]
  private val others    = new ListBuffer[String]

  def addOption(option: String): Unit = options += option

  def addArgument(option: String, arg: String): Unit = arguments(option) = arg

  def addPrefixed(prefix: String, arg: String): Unit =
    prefixes.getOrElseUpdate(prefix, new mutable.HashSet) += arg

  def addBinding(tag: String, key: String, value: String): Unit =
    if (key.length > 0)
      bindings.getOrElseUpdate(tag, new mutable.HashMap)(key) = value

  def addBinding(tag: String, binding: Tuple2[String, String]): Unit =
    addBinding(tag, binding._1, binding._2)

  def addOther(arg: String): Unit = others += arg

  def contains(option: String): Boolean = options(option)

  def getArgument(option: String): Option[String] = arguments get option

  def getSuffixes(prefix: String): mutable.Set[String] =
    prefixes.getOrElse(prefix, new mutable.HashSet)

  def containsSuffix(prefix: String, suffix: String): Boolean =
    prefixes get prefix exists (set => set(suffix))

  def getBindings(tag: String): mutable.Map[String, String] =
    bindings.getOrElse(tag, new mutable.HashMap)

  def getBinding(option: String, key: String): Option[String] =
    bindings get option flatMap (_ get key)

  def getOthers: List[String] = others.toList
}