在Scala中解析命令行参数的最佳方法是什么? 我个人更喜欢一些不需要外部罐子的轻量级的东西。

相关:

我如何解析Java中的命令行参数? c++有哪些参数解析器库? 在c#中解析命令行参数的最佳方法


当前回答

我的方法基于上面的答案(来自dave4420),并试图通过使其更通用来改进它。

它返回所有命令行参数的映射[String,String] 你可以查询你想要的特定参数(例如使用.contains)或将值转换为你想要的类型(例如使用toInt)。

def argsToOptionMap(args:Array[String]):Map[String,String]= {
  def nextOption(
      argList:List[String], 
      map:Map[String, String]
    ) : Map[String, String] = {
    val pattern       = "--(\\w+)".r // Selects Arg from --Arg
    val patternSwitch = "-(\\w+)".r  // Selects Arg from -Arg
    argList match {
      case Nil => map
      case pattern(opt)       :: value  :: tail => nextOption( tail, map ++ Map(opt->value) )
      case patternSwitch(opt) :: tail => nextOption( tail, map ++ Map(opt->null) )
      case string             :: Nil  => map ++ Map(string->null)
      case option             :: tail => {
        println("Unknown option:"+option) 
        sys.exit(1)
      }
    }
  }
  nextOption(args.toList,Map())
}

例子:

val args=Array("--testing1","testing1","-a","-b","--c","d","test2")
argsToOptionMap( args  )

给:

res0: Map[String,String] = Map(testing1 -> testing1, a -> null, b -> null, c -> d, test2 -> null)

其他回答

Here's a scala command line parser that is easy to use. It automatically formats help text, and it converts switch arguments to your desired type. Both short POSIX, and long GNU style switches are supported. Supports switches with required arguments, optional arguments, and multiple value arguments. You can even specify the finite list of acceptable values for a particular switch. Long switch names can be abbreviated on the command line for convenience. Similar to the option parser in the Ruby standard library.

我喜欢这段代码的简洁外观…从这里的讨论中收集到: http://www.scala-lang.org/old/node/4380

object ArgParser {
  val usage = """
Usage: parser [-v] [-f file] [-s sopt] ...
Where: -v   Run verbosely
       -f F Set input file to F
       -s S Set Show option to S
"""

  var filename: String = ""
  var showme: String = ""
  var debug: Boolean = false
  val unknown = "(^-[^\\s])".r

  val pf: PartialFunction[List[String], List[String]] = {
    case "-v" :: tail => debug = true; tail
    case "-f" :: (arg: String) :: tail => filename = arg; tail
    case "-s" :: (arg: String) :: tail => showme = arg; tail
    case unknown(bad) :: tail => die("unknown argument " + bad + "\n" + usage)
  }

  def main(args: Array[String]) {
    // if there are required args:
    if (args.length == 0) die()
    val arglist = args.toList
    val remainingopts = parseArgs(arglist,pf)

    println("debug=" + debug)
    println("showme=" + showme)
    println("filename=" + filename)
    println("remainingopts=" + remainingopts)
  }

  def parseArgs(args: List[String], pf: PartialFunction[List[String], List[String]]): List[String] = args match {
    case Nil => Nil
    case _ => if (pf isDefinedAt args) parseArgs(pf(args),pf) else args.head :: parseArgs(args.tail,pf)
  }

  def die(msg: String = usage) = {
    println(msg)
    sys.exit(1)
  }

}

另一个库:scarg

我刚刚在scalac的scala.tools.cmd包中找到了一个广泛的命令行解析库。

参见http://www.assembla.com/code/scala-eclipse-toolchain/git/nodes/src/compiler/scala/tools/cmd?rev=f59940622e32384b1e08939effd24e924a8ba8db

我建议使用http://docopt.org/。有一个scala端口,但是Java实现https://github.com/docopt/docopt.java工作得很好,而且似乎维护得更好。这里有一个例子:

import org.docopt.Docopt

import scala.collection.JavaConversions._
import scala.collection.JavaConverters._

val doc =
"""
Usage: my_program [options] <input>

Options:
 --sorted   fancy sorting
""".stripMargin.trim

//def args = "--sorted test.dat".split(" ").toList
var results = new Docopt(doc).
  parse(args()).
  map {case(key, value)=>key ->value.toString}

val inputFile = new File(results("<input>"))
val sorted = results("--sorted").toBoolean