add eval (-e) expression evaluation to command line

compiler/src/dotty/tools/MainGenericRunner.scala

@@ -4,28 +4,26 @@ package dotty.tools
 import scala.annotation.tailrec
 import scala.io.Source
 import scala.util.{ Try, Success, Failure }
-import java.net.URLClassLoader
-import sys.process._
 import java.io.File
 import java.lang.Thread
 import scala.annotation.internal.sharable
 import dotty.tools.dotc.util.ClasspathFromClassloader
 import dotty.tools.runner.ObjectRunner
 import dotty.tools.dotc.config.Properties.envOrNone
 import java.util.jar._
-import java.util.jar.Attributes.Name
 import dotty.tools.io.Jar
 import dotty.tools.runner.ScalaClassLoader
 import java.nio.file.{Files, Paths, Path}
-import scala.collection.JavaConverters._
 import dotty.tools.dotc.config.CommandLineParser
+import dotty.tools.scripting.StringDriver
 
 enum ExecuteMode:
   case Guess
   case Script
   case Repl
   case Run
   case PossibleRun
+  case Expression
 
 case class Settings(
   verbose: Boolean = false,
@@ -38,6 +36,7 @@ case class Settings(
   possibleEntryPaths: List[String] = List.empty,
   scriptArgs: List[String] = List.empty,
   targetScript: String = "",
+  targetExpression: String = "",
   targetToRun: String = "",
   save: Boolean = false,
   modeShouldBePossibleRun: Boolean = false,
@@ -78,6 +77,9 @@ case class Settings(
   def withTargetToRun(targetToRun: String): Settings =
     this.copy(targetToRun = targetToRun)
 
+  def withExpression(scalaSource: String): Settings =
+    this.copy(targetExpression = scalaSource)
+
   def withSave: Settings =
     this.copy(save = true)
 
@@ -150,12 +152,12 @@ object MainGenericRunner {
     case (o @ colorOption(_*)) :: tail =>
       process(tail, settings.withScalaArgs(o))
     case "-e" :: expression :: tail =>
-      val tempScript = writeFile(s"@main def main(args: String *): Unit =\n  ${expression}")
+      val mainSource = s"@main def main(args: String *): Unit =\n  ${expression}"
       settings
-        .withExecuteMode(ExecuteMode.Script)
-        .withTargetScript(tempScript)
+        .withExecuteMode(ExecuteMode.Expression)
+        .withExpression(mainSource)
         .withScriptArgs(tail*)
-        .noSave // useless
+        .noSave // -save not useful here
     case arg :: tail =>
       val line = Try(Source.fromFile(arg).getLines.toList).toOption.flatMap(_.headOption)
       lazy val hasScalaHashbang = { val s = line.getOrElse("") ; s.startsWith("#!") && s.contains("scala") }
@@ -243,6 +245,16 @@ object MainGenericRunner {
               ++ List("-script", settings.targetScript)
               ++ settings.scriptArgs
           scripting.Main.main(properArgs.toArray)
+      case ExecuteMode.Expression =>
+        val cp = settings.classPath match {
+          case Nil => ""
+          case list => list.mkString(classpathSeparator)
+        }
+        val cpArgs = if cp.isEmpty then Nil else List("-classpath", cp)
+        val properArgs = cpArgs ++ settings.residualArgs ++ settings.scalaArgs
+        val driver = StringDriver(properArgs.toArray, settings.targetExpression)
+        driver.compileAndRun(settings.classPath)
+
       case ExecuteMode.Guess =>
         if settings.modeShouldBePossibleRun then
           run(settings.withExecuteMode(ExecuteMode.PossibleRun))
@@ -259,11 +271,4 @@ object MainGenericRunner {
     e.foreach(_.printStackTrace())
     !isFailure
   }
-  def writeFile(contents: String): String = {
-    val file = Files.createTempFile("exec", ".scala")
-    file.toFile.deleteOnExit()
-    Files.write(file, contents.getBytes)
-    file.toString.replace('\\', '/')
-  }
-
 }

compiler/src/dotty/tools/scripting/ScriptingDriver.scala

@@ -2,19 +2,12 @@ package dotty.tools.scripting
 
 import java.nio.file.{ Files, Paths, Path }
 import java.io.File
-import java.net.{ URL, URLClassLoader }
-import java.lang.reflect.{ Modifier, Method }
+import java.net.{ URLClassLoader }
 
-import scala.jdk.CollectionConverters._
-
-import dotty.tools.dotc.{ Driver, Compiler }
-import dotty.tools.dotc.core.Contexts, Contexts.{ Context, ContextBase, ctx }
-import dotty.tools.dotc.config.CompilerCommand
+import dotty.tools.dotc.Driver
+import dotty.tools.dotc.core.Contexts, Contexts.{ Context, ctx }
 import dotty.tools.io.{ PlainDirectory, Directory, ClassPath }
-import dotty.tools.dotc.reporting.Reporter
-import dotty.tools.dotc.config.Settings.Setting._
-
-import sys.process._
+import Util.*
 
 class ScriptingDriver(compilerArgs: Array[String], scriptFile: File, scriptArgs: Array[String]) extends Driver:
   def compileAndRun(pack:(Path, Seq[Path], String) => Boolean = null): Unit =
@@ -31,7 +24,7 @@ class ScriptingDriver(compilerArgs: Array[String], scriptFile: File, scriptArgs:
         try
           val classpath = s"${ctx.settings.classpath.value}${pathsep}${sys.props("java.class.path")}"
           val classpathEntries: Seq[Path] = ClassPath.expandPath(classpath, expandStar=true).map { Paths.get(_) }
-          val (mainClass, mainMethod) = detectMainClassAndMethod(outDir, classpathEntries, scriptFile)
+          val (mainClass, mainMethod) = detectMainClassAndMethod(outDir, classpathEntries, scriptFile.toString)
           val invokeMain: Boolean =
             Option(pack) match
               case Some(func) =>
@@ -48,58 +41,6 @@ class ScriptingDriver(compilerArgs: Array[String], scriptFile: File, scriptArgs:
       case None =>
   end compileAndRun
 
-  private def deleteFile(target: File): Unit =
-    if target.isDirectory then
-      for member <- target.listFiles.toList
-      do deleteFile(member)
-    target.delete()
-  end deleteFile
-
-  private def detectMainClassAndMethod(outDir: Path, classpathEntries: Seq[Path],
-      scriptFile: File): (String, Method) =
-
-    val classpathUrls = (classpathEntries :+ outDir).map { _.toUri.toURL }
-
-    val cl = URLClassLoader(classpathUrls.toArray)
-
-    def collectMainMethods(target: File, path: String): List[(String, Method)] =
-      val nameWithoutExtension = target.getName.takeWhile(_ != '.')
-      val targetPath =
-        if path.nonEmpty then s"${path}.${nameWithoutExtension}"
-        else nameWithoutExtension
-
-      if target.isDirectory then
-        for
-          packageMember <- target.listFiles.toList
-          membersMainMethod <- collectMainMethods(packageMember, targetPath)
-        yield membersMainMethod
-      else if target.getName.endsWith(".class") then
-        val cls = cl.loadClass(targetPath)
-        try
-          val method = cls.getMethod("main", classOf[Array[String]])
-          if Modifier.isStatic(method.getModifiers) then List((cls.getName, method)) else Nil
-        catch
-          case _: java.lang.NoSuchMethodException => Nil
-      else Nil
-    end collectMainMethods
-
-    val candidates = for
-      file <- outDir.toFile.listFiles.toList
-      method <- collectMainMethods(file, "")
-    yield method
-
-    candidates match
-      case Nil =>
-        throw ScriptingException(s"No main methods detected in script ${scriptFile}")
-      case _ :: _ :: _ =>
-        throw ScriptingException("A script must contain only one main method. " +
-          s"Detected the following main methods:\n${candidates.mkString("\n")}")
-      case m :: Nil => m
-    end match
-  end detectMainClassAndMethod
-
-  def pathsep = sys.props("path.separator")
-
 end ScriptingDriver
 
 case class ScriptingException(msg: String) extends RuntimeException(msg)

compiler/src/dotty/tools/scripting/StringDriver.scala

@@ -0,0 +1,45 @@
+package dotty.tools.scripting
+
+import java.nio.file.{ Files, Paths, Path }
+
+import dotty.tools.dotc.Driver
+import dotty.tools.dotc.core.Contexts, Contexts.{ Context, ctx }
+import dotty.tools.io.{ PlainDirectory, Directory, ClassPath }
+import Util.*
+
+class StringDriver(compilerArgs: Array[String], scalaSource: String) extends Driver:
+  override def sourcesRequired: Boolean = false
+
+  def compileAndRun(classpath: List[String] = Nil): Unit =
+    val outDir = Files.createTempDirectory("scala3-expression")
+    outDir.toFile.deleteOnExit()
+
+    setup(compilerArgs, initCtx.fresh) match
+      case Some((toCompile, rootCtx)) =>
+        given Context = rootCtx.fresh.setSetting(rootCtx.settings.outputDir,
+          new PlainDirectory(Directory(outDir)))
+
+        val compiler = newCompiler
+        compiler.newRun.compileFromStrings(List(scalaSource))
+
+        val output = ctx.settings.outputDir.value
+        if ctx.reporter.hasErrors then
+          throw StringDriverException("Errors encountered during compilation")
+
+        try
+          val classpath = s"${ctx.settings.classpath.value}${pathsep}${sys.props("java.class.path")}"
+          val classpathEntries: Seq[Path] = ClassPath.expandPath(classpath, expandStar=true).map { Paths.get(_) }
+          sys.props("java.class.path") = classpathEntries.map(_.toString).mkString(pathsep)
+          val (mainClass, mainMethod) = detectMainClassAndMethod(outDir, classpathEntries, scalaSource)
+          mainMethod.invoke(null, Array.empty[String])
+        catch
+          case e: java.lang.reflect.InvocationTargetException =>
+            throw e.getCause
+        finally
+          deleteFile(outDir.toFile)
+      case None =>
+  end compileAndRun
+
+end StringDriver
+
+case class StringDriverException(msg: String) extends RuntimeException(msg)

compiler/src/dotty/tools/scripting/Util.scala

@@ -0,0 +1,60 @@
+package dotty.tools.scripting
+
+import java.nio.file.{ Path }
+import java.io.File
+import java.net.{ URLClassLoader }
+import java.lang.reflect.{ Modifier, Method }
+
+object Util:
+
+  def deleteFile(target: File): Unit =
+    if target.isDirectory then
+      for member <- target.listFiles.toList
+      do deleteFile(member)
+    target.delete()
+  end deleteFile
+
+  def detectMainClassAndMethod(outDir: Path, classpathEntries: Seq[Path], srcFile: String): (String, Method) =
+    val classpathUrls = (classpathEntries :+ outDir).map { _.toUri.toURL }
+    val cl = URLClassLoader(classpathUrls.toArray)
+
+    def collectMainMethods(target: File, path: String): List[(String, Method)] =
+      val nameWithoutExtension = target.getName.takeWhile(_ != '.')
+      val targetPath =
+        if path.nonEmpty then s"${path}.${nameWithoutExtension}"
+        else nameWithoutExtension
+
+      if target.isDirectory then
+        for
+          packageMember <- target.listFiles.toList
+          membersMainMethod <- collectMainMethods(packageMember, targetPath)
+        yield membersMainMethod
+      else if target.getName.endsWith(".class") then
+        val cls = cl.loadClass(targetPath)
+        try
+          val method = cls.getMethod("main", classOf[Array[String]])
+          if Modifier.isStatic(method.getModifiers) then List((cls.getName, method)) else Nil
+        catch
+          case _: java.lang.NoSuchMethodException => Nil
+      else Nil
+    end collectMainMethods
+
+    val mains = for
+      file <- outDir.toFile.listFiles.toList
+      method <- collectMainMethods(file, "")
+    yield method
+
+    mains match
+      case Nil =>
+        throw StringDriverException(s"No main methods detected for [${srcFile}]")
+      case _ :: _ :: _ =>
+        throw StringDriverException(
+          s"internal error: Detected the following main methods:\n${mains.mkString("\n")}")
+      case m :: Nil => m
+    end match
+  end detectMainClassAndMethod
+
+  def pathsep = sys.props("path.separator")
+
+end Util
+

compiler/test/dotty/tools/scripting/BashScriptsTests.scala

@@ -2,6 +2,7 @@ package dotty
 package tools
 package scripting
 
+import java.nio.file.Paths
 import org.junit.{Test, AfterClass}
 import org.junit.Assert.assertEquals
 
@@ -195,6 +196,8 @@ class BashScriptsTests:
     val scriptBase = "sqlDateError"
     val scriptFile = testFiles.find(_.getName == s"$scriptBase.sc").get
     val testJar = testFile(s"$scriptBase.jar") // jar should not be created when scriptFile runs
+    val tj = Paths.get(testJar).toFile
+    if tj.isFile then tj.delete() // discard residual debris from previous test
     printf("===> verify '-save' is cancelled by '-nosave' in script hashbang.`\n")
     val (validTest, exitCode, stdout, stderr) = bashCommand(s"SCALA_OPTS=-save ${scriptFile.absPath}")
     printf("stdout: %s\n", stdout.mkString("\n","\n",""))

compiler/test/dotty/tools/scripting/ExpressionTest.scala

@@ -0,0 +1,49 @@
+package dotty
+package tools
+package scripting
+
+import java.nio.file.Paths
+import org.junit.{Test, AfterClass}
+import org.junit.Assert.assertEquals
+
+import vulpix.TestConfiguration
+
+import ScriptTestEnv.*
+
+/** 
+ *   +. test scala -e <expression>
+ */
+class ExpressionTest:
+  /*
+   * verify -e <expression> works.
+   */
+  @Test def verifyCommandLineExpression =
+    printf("===> verify -e <expression> is properly handled by `dist/bin/scala`\n")
+    val expected = "9"
+    val expression = s"println(3*3)"
+    val result = getResult(expression)
+    assert(result.contains(expected), s"expression [$expression] did not send [$expected] to stdout")
+
+  @Test def verifyImports: Unit =
+    val expressionLines = List(
+      "import java.nio.file.Paths",
+      """val cwd = Paths.get(""."")""",
+      """println(cwd.toFile.listFiles.toList.filter(_.isDirectory).size)""",
+    )
+    val expression = expressionLines.mkString(";")
+    testExpression(expression){ result =>
+      result.matches("[0-9]+") && result.toInt > 0
+    }
+
+  def getResult(expression: String): String =
+    val cmd = s"bin/scala -e $expression"
+    val (_, _, stdout, stderr) = bashCommand(s"""bin/scala -e '$expression'""")
+    printf("stdout: %s\n", stdout.mkString("|"))
+    printf("stderr: %s\n", stderr.mkString("\n","\n",""))
+    stdout.filter(_.nonEmpty).mkString("")
+
+  def testExpression(expression: String)(check: (result: String) => Boolean) = {
+    val result = getResult(expression)
+    check(result)
+  }
+