scala 如何在脚本运行时运行生成的代码？

yzuktlbb  于 2022-11-23  发布在  Scala
关注(0)|答案(1)|浏览(164)

在scala脚本运行期间，我希望它生成一些代码并执行这些代码。
我以为我在网上找到了两个可能有用的例子，但它们都不成功

import scala.reflect.runtime.universe._
import scala.reflect.runtime.currentMirror
import scala.tools.reflect.ToolBox
import java.io.{File, FileWriter}

  def runstuff() = {

    val fileWriter = new FileWriter(new File("temporaryScalaFile.scala"))
    fileWriter.write("println(\"hello\")")
    fileWriter.close()
    temporaryScalaFile.scala

    val cm = scala.reflect.runtime.universe.runtimeMirror(getClass.getClassLoader)
    val tb = cm.mkToolBox()
    val str = tb.eval(tb.parse("new String(\"Yo\")"))
    println(str)

  }

这些可能是过时的例子。
有没有人有一个工作或修复？

scala

1条答案

按热度按时间
mkh04yzy

mkh04yzy1#

我将在Scala 2中采用我在How to compile and execute scala code at run-time in Scala3?中的答案

ammonite.Main(verboseOutput = false).runCode("""println("Hello, World!")""")
// Hello, World!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies += "com.lihaoyi" % "ammonite" % "2.5.4" cross CrossVersion.full
scala.tools.nsc.interpreter.shell.Scripted()
  .eval("""System.out.println("Hello, World!")""")
// Hello, World!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies ++= scalaOrganization.value % "scala-compiler" % scalaVersion.value
  • 您可以使用Scala 2反射工具箱
val tb = scala.tools.reflect.ToolBox(scala.reflect.runtime.currentMirror).mkToolBox()
tb.eval(tb.parse("""println("Hello, world!")"""))
// Hello, world!

或

import scala.tools.reflect.ToolBox // implicit

val tb = scala.reflect.runtime.currentMirror.mkToolBox()
tb.eval(tb.parse("""println("Hello, world!")"""))
// Hello, world!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies ++= scalaOrganization.value % "scala-compiler" % scalaVersion.value
  • 您可以使用scala.tools.nsc.interpreter
val settings = new scala.tools.nsc.Settings
settings.usejavacp.value = true
new scala.tools.nsc.interpreter.IMain(settings,
  new scala.tools.nsc.interpreter.shell.ReplReporterImpl(settings)
).interpret("""println("Hello, World!")""")
// Hello, World!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies ++= scalaOrganization.value % "scala-compiler" % scalaVersion.value
  • 如果你有一个scala.reflect.runtime.universe.Treeq"..."而不是普通字符串，那么你不需要解析
import scala.reflect.runtime.universe.Quasiquote // implicit for q"..." interpolator
import scala.tools.reflect.ToolBox               // implicit for .eval

scala.reflect.runtime.currentMirror.mkToolBox()
  .eval(q"""println("Hello, World!")""") // Hello, World!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies ++= scalaOrganization.value % "scala-compiler" % scalaVersion.value
  • 如果你有一个scala.reflect.runtime.universe.Exprreify {...}（一个静态类型的树 Package 器）而不是普通字符串，那么你也不需要解析
import scala.reflect.runtime.universe.reify
import scala.tools.reflect.ToolBox

scala.reflect.runtime.currentMirror.mkToolBox()
  .eval(reify{ println("Hello, World!") }.tree) 
// Hello, World!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies ++= scalaOrganization.value % "scala-compiler" % scalaVersion.value
  • 以上所有内容都是为了在Scala 2中运行Scala 2代码。如果我们想在Scala 2中运行Scala 3代码，那么我们可以使用标准的Scala 3 REPL interpreter
(new dotty.tools.repl.ScriptEngine).eval("""println("Hello, World!")""")
// Hello, World!
  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies += scalaOrganization.value %% "scala3-compiler" % "3.1.3" cross CrossVersion.for2_13Use3
scalacOptions += "-Ytasty-reader"
  • 您也可以使用JSR223脚本。根据您的类路径中是scala-compiler还是scala3-compiler，您将运行Scala 2或Scala 3（上述两个脚本引擎之一：Scala 2 scala.tools.nsc.interpreter.shell.Scripted或Scala 3 dotty.tools.repl.ScriptEngine）。如果同时添加了两个依赖项，则先添加的依赖项优先。
new javax.script.ScriptEngineManager(getClass.getClassLoader)
  .getEngineByName("scala")
  .eval("""println("Hello, World!")""")
// Hello, World!

如果您希望更好地控制所使用的依赖项（无需重新导入项目），则可以使用Coursier并指定类加载器

import coursier._ // libraryDependencies += "io.get-coursier" %% "coursier" % "2.1.0-M6-53-gb4f448130"
val files = Fetch()
  .addDependencies(
    Dependency(Module(Organization("org.scala-lang"), ModuleName("scala-compiler")), "2.13.9"),
    // Dependency(Module(Organization("org.scala-lang"), ModuleName("scala3-compiler_3")), "3.2.0"),
  )
  .run()

val classLoader = new java.net.URLClassLoader(
  files.map(_.toURI.toURL).toArray,
  /*getClass.getClassLoader*/null // ignoring current classpath
)
new javax.script.ScriptEngineManager(classLoader)
  .getEngineByName("scala")
  .eval("""
    type T = List[Option[A]] forSome {type A} // Scala 2
    //type T = [A] =>> [B] =>> (A, B) // Scala 3
    System.out.println("Hello, World!")
  """)
// Hello, World!
  • 您可以使用实际的编译器在Scala 2中自己实现Eval
import scala.reflect.internal.util.{AbstractFileClassLoader, BatchSourceFile}
import scala.reflect.io.{AbstractFile, VirtualDirectory}
import scala.reflect.runtime.universe
import scala.reflect.runtime
import scala.reflect.runtime.universe.{Mirror, TermName}
import scala.tools.nsc.{Global, Settings}

val code =
  s"""
     |package mypackage
     |
     |object Main {
     |  def main(args: Array[String]): Unit = {
     |    println("Hello, World!")
     |  }
     |}""".stripMargin

val directory = new VirtualDirectory("(memory)", None)
val runtimeMirror = createRuntimeMirror(directory, runtime.currentMirror)
compileCode(code, List(), directory)
runObjectMethod("mypackage.Main", runtimeMirror, "main", Array.empty[String])
// Hello, World!

def compileCode(
                 code: String,
                 classpathDirectories: List[AbstractFile],
                 outputDirectory: AbstractFile
               ): Unit = {
  val settings = new Settings
  classpathDirectories.foreach(dir => settings.classpath.prepend(dir.toString))
  settings.outputDirs.setSingleOutput(outputDirectory)
  settings.usejavacp.value = true
  val global = new Global(settings)
  val run = new global.Run
  run.compileSources(List(new BatchSourceFile("(inline)", code)))
  // val unit = run.units.next()
  // println("source=" + unit.source.content.mkString)
  // println("typed tree=" + unit.body)
}

def runObjectMethod(
                     objectName: String,
                     runtimeMirror: Mirror,
                     methodName: String,
                     arguments: Any*
                   ): Any = {
  val objectSymbol         = runtimeMirror.staticModule(objectName)
  val objectModuleMirror   = runtimeMirror.reflectModule(objectSymbol)
  val objectInstance       = objectModuleMirror.instance
  val objectType           = objectSymbol.typeSignature
  val methodSymbol         = objectType.decl(TermName(methodName)).asMethod
  val objectInstanceMirror = runtimeMirror.reflect(objectInstance)
  val methodMirror         = objectInstanceMirror.reflectMethod(methodSymbol)
  methodMirror(arguments: _*)
}

def createRuntimeMirror(directory: AbstractFile, parentMirror: Mirror): Mirror = {
  val classLoader = new AbstractFileClassLoader(directory, parentMirror.classLoader)
  universe.runtimeMirror(classLoader)
}

型

  • 构建. sbt *
scalaVersion := "2.13.8"
libraryDependencies ++= scalaOrganization.value % "scala-compiler" % scalaVersion.value
  • 同样，ScalametaSemanticdb具有方法scala.meta.interactive.InteractiveSemanticdb.newCompiler()，该方法返回在scala.tools.nsc.Global之上扩展的scala.tools.nsc.interactive.Global。
  • 构建. sbt *
scalaVersion := "2.13.8"
// adding as a dependency, not a compiler plugin
libraryDependencies += "org.scalameta" % "semanticdb-scalac" % "4.6.0" cross CrossVersion.full

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