タスクランナーを作る/動的コンパイルさせるコード

動的コンパイルさせるコード

code:runner.scala

//> using scala 3.8.3

//> using dep org.scala-lang::scala3-compiler:3.8.3

import dotty.tools.dotc.Main

import java.net.URLClassLoader

import java.nio.file.{Files, Path, Paths}

object ScriptRunner {

private val EntryPoint = "__scriptMain"

def run(

sourceFile: Path,

): Unit = {

val srcDir = Files.createTempDirectory("scala-src-")

val outDir = Files.createTempDirectory("scala-out-")

try {

val body = Files.readString(sourceFile)

val importLines = extraImports.map(i => s"import $i").mkString("\n")

// ファイル本体を @main 関数で包む

val wrapped =

s"""$importLines

|

|@main def $EntryPoint(args: String*): Unit = {

|$body

|}

|""".stripMargin

val patched = srcDir.resolve(sourceFile.getFileName.toString)

Files.writeString(patched, wrapped)

val classpath = System.getProperty("java.class.path")

val args = Array(

"-d", outDir.toString,

"-classpath", classpath,

patched.toString

)

val reporter = Main.process(args)

if (reporter.hasErrors) {

throw new RuntimeException(

s"コンパイルに失敗しました(エラー件数: ${reporter.errorCount})"

)

}

val loader = new URLClassLoader(

Array(outDir.toUri.toURL),

getClass.getClassLoader

)

val cls = loader.loadClass(EntryPoint)

mainM.invoke(null, programArgs)

} finally {

def deleteRecursively(p: Path): Unit = {

if (Files.isDirectory(p)) {

Files.list(p).forEach(deleteRecursively)

}

Files.deleteIfExists(p)

}

deleteRecursively(srcDir)

deleteRecursively(outDir)

}

}

}

@main def runScript(programArgs: String*): Unit = {

ScriptRunner.run(

sourceFile = Paths.get("Hello.scala"),

extraImports = Seq(

"scala.collection.mutable",

"java.time.LocalDate"

),

programArgs = programArgs.toArray

)

}