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
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
其他回答
命令行接口Scala Toolkit (CLIST)
这也是我的!(虽然有点晚了)
https://github.com/backuity/clist
与scopt相反,它是完全可变的…但是等等!这给了我们一个很好的语法:
class Cat extends Command(description = "concatenate files and print on the standard output") {
// type-safety: members are typed! so showAll is a Boolean
var showAll = opt[Boolean](abbrev = "A", description = "equivalent to -vET")
var numberNonblank = opt[Boolean](abbrev = "b", description = "number nonempty output lines, overrides -n")
// files is a Seq[File]
var files = args[Seq[File]](description = "files to concat")
}
还有一个简单的运行方法:
Cli.parse(args).withCommand(new Cat) { case cat =>
println(cat.files)
}
当然,您可以做更多的事情(多命令,许多配置选项,……),并且没有依赖性。
我将以一种独特的特性来结束,默认用法(对于多个命令经常被忽略):
我来自Java世界,我喜欢args4j,因为它简单,规范更可读(多亏了注释),并产生了格式化良好的输出。
下面是我的例子片段:
规范
import org.kohsuke.args4j.{CmdLineException, CmdLineParser, Option}
object CliArgs {
@Option(name = "-list", required = true,
usage = "List of Nutch Segment(s) Part(s)")
var pathsList: String = null
@Option(name = "-workdir", required = true,
usage = "Work directory.")
var workDir: String = null
@Option(name = "-master",
usage = "Spark master url")
var masterUrl: String = "local[2]"
}
解析
//var args = "-listt in.txt -workdir out-2".split(" ")
val parser = new CmdLineParser(CliArgs)
try {
parser.parseArgument(args.toList.asJava)
} catch {
case e: CmdLineException =>
print(s"Error:${e.getMessage}\n Usage:\n")
parser.printUsage(System.out)
System.exit(1)
}
println("workDir :" + CliArgs.workDir)
println("listFile :" + CliArgs.pathsList)
println("master :" + CliArgs.masterUrl)
关于无效论证
Error:Option "-list" is required
Usage:
-list VAL : List of Nutch Segment(s) Part(s)
-master VAL : Spark master url (default: local[2])
-workdir VAL : Work directory.
这在很大程度上是我对同一主题的Java问题的答案的无耻克隆。事实证明,JewelCLI是scala友好的,因为它不需要JavaBean样式的方法来获得自动参数命名。
JewelCLI是一个scala友好的Java库,用于命令行解析,生成干净的代码。它使用带有注解的代理接口来动态地为命令行参数构建类型安全的API。
一个参数接口Person.scala的例子:
import uk.co.flamingpenguin.jewel.cli.Option
trait Person {
@Option def name: String
@Option def times: Int
}
参数接口Hello.scala的用法示例:
import uk.co.flamingpenguin.jewel.cli.CliFactory.parseArguments
import uk.co.flamingpenguin.jewel.cli.ArgumentValidationException
object Hello {
def main(args: Array[String]) {
try {
val person = parseArguments(classOf[Person], args:_*)
for (i <- 1 to (person times))
println("Hello " + (person name))
} catch {
case e: ArgumentValidationException => println(e getMessage)
}
}
}
将上述文件的副本保存到一个目录中,并将JewelCLI 0.6 JAR下载到该目录中。
在Linux/Mac OS X/etc / Bash中编译并运行示例:
scalac -cp jewelcli-0.6.jar:. Person.scala Hello.scala
scala -cp jewelcli-0.6.jar:. Hello --name="John Doe" --times=3
在Windows命令提示符中编译并运行示例:
scalac -cp jewelcli-0.6.jar;. Person.scala Hello.scala
scala -cp jewelcli-0.6.jar;. Hello --name="John Doe" --times=3
运行该示例应该产生以下输出:
Hello John Doe
Hello John Doe
Hello John Doe
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)
}
}
我知道这个问题是很久以前问过的,但我认为它可能会帮助一些人,谁是谷歌周围(像我),并点击这个页面。
扇贝看起来也很有希望。
特点(引用自链接的github页面):
标志,单值和多值选项 posix风格的短选项名称(-a)带有分组(-abc) gnu风格的长选项名称(——opt) 属性参数(-Dkey=value, -D key1=value key2=value) 非字符串类型的选项和属性值(带有可扩展转换器) 对尾随参数的强大匹配 子命令
还有一些示例代码(也来自Github页面):
import org.rogach.scallop._;
object Conf extends ScallopConf(List("-c","3","-E","fruit=apple","7.2")) {
// all options that are applicable to builder (like description, default, etc)
// are applicable here as well
val count:ScallopOption[Int] = opt[Int]("count", descr = "count the trees", required = true)
.map(1+) // also here work all standard Option methods -
// evaluation is deferred to after option construction
val properties = props[String]('E')
// types (:ScallopOption[Double]) can be omitted, here just for clarity
val size:ScallopOption[Double] = trailArg[Double](required = false)
}
// that's it. Completely type-safe and convenient.
Conf.count() should equal (4)
Conf.properties("fruit") should equal (Some("apple"))
Conf.size.get should equal (Some(7.2))
// passing into other functions
def someInternalFunc(conf:Conf.type) {
conf.count() should equal (4)
}
someInternalFunc(Conf)