Scala example source code file (ILoop.scala)
The ILoop.scala Scala example source code
/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Alexander Spoon
*/
package scala
package tools.nsc
package interpreter
import scala.language.{ implicitConversions, existentials }
import scala.annotation.tailrec
import Predef.{ println => _, _ }
import interpreter.session._
import StdReplTags._
import scala.util.Properties.{ jdkHome, javaVersion, versionString, javaVmName }
import scala.tools.nsc.util.{ ClassPath, Exceptional, stringFromWriter, stringFromStream }
import scala.reflect.classTag
import scala.reflect.internal.util.{ BatchSourceFile, ScalaClassLoader }
import ScalaClassLoader._
import scala.reflect.io.{ File, Directory }
import scala.tools.util._
import scala.collection.generic.Clearable
import scala.concurrent.{ ExecutionContext, Await, Future, future }
import ExecutionContext.Implicits._
import java.io.{ BufferedReader, FileReader }
/** The Scala interactive shell. It provides a read-eval-print loop
* around the Interpreter class.
* After instantiation, clients should call the main() method.
*
* If no in0 is specified, then input will come from the console, and
* the class will attempt to provide input editing feature such as
* input history.
*
* @author Moez A. Abdel-Gawad
* @author Lex Spoon
* @version 1.2
*/
class ILoop(in0: Option[BufferedReader], protected val out: JPrintWriter)
extends AnyRef
with LoopCommands
{
def this(in0: BufferedReader, out: JPrintWriter) = this(Some(in0), out)
def this() = this(None, new JPrintWriter(Console.out, true))
@deprecated("Use `intp` instead.", "2.9.0") def interpreter = intp
@deprecated("Use `intp` instead.", "2.9.0") def interpreter_= (i: Interpreter): Unit = intp = i
var in: InteractiveReader = _ // the input stream from which commands come
var settings: Settings = _
var intp: IMain = _
private var globalFuture: Future[Boolean] = _
/** Print a welcome message */
def printWelcome() {
echo(s"""
|Welcome to Scala $versionString ($javaVmName, Java $javaVersion).
|Type in expressions to have them evaluated.
|Type :help for more information.""".trim.stripMargin
)
replinfo("[info] started at " + new java.util.Date)
}
protected def asyncMessage(msg: String) {
if (isReplInfo || isReplPower)
echoAndRefresh(msg)
}
override def echoCommandMessage(msg: String) {
intp.reporter printUntruncatedMessage msg
}
lazy val power = new Power(intp, new StdReplVals(this))(tagOfStdReplVals, classTag[StdReplVals])
def history = in.history
// classpath entries added via :cp
var addedClasspath: String = ""
/** A reverse list of commands to replay if the user requests a :replay */
var replayCommandStack: List[String] = Nil
/** A list of commands to replay if the user requests a :replay */
def replayCommands = replayCommandStack.reverse
/** Record a command for replay should the user request a :replay */
def addReplay(cmd: String) = replayCommandStack ::= cmd
def savingReplayStack[T](body: => T): T = {
val saved = replayCommandStack
try body
finally replayCommandStack = saved
}
def savingReader[T](body: => T): T = {
val saved = in
try body
finally in = saved
}
/** Close the interpreter and set the var to null. */
def closeInterpreter() {
if (intp ne null) {
intp.close()
intp = null
}
}
class ILoopInterpreter extends IMain(settings, out) {
outer =>
override lazy val formatting = new Formatting {
def prompt = ILoop.this.prompt
}
override protected def parentClassLoader =
settings.explicitParentLoader.getOrElse( classOf[ILoop].getClassLoader )
}
/** Create a new interpreter. */
def createInterpreter() {
if (addedClasspath != "")
settings.classpath append addedClasspath
intp = new ILoopInterpreter
}
/** print a friendly help message */
def helpCommand(line: String): Result = {
if (line == "") helpSummary()
else uniqueCommand(line) match {
case Some(lc) => echo("\n" + lc.help)
case _ => ambiguousError(line)
}
}
private def helpSummary() = {
val usageWidth = commands map (_.usageMsg.length) max
val formatStr = "%-" + usageWidth + "s %s"
echo("All commands can be abbreviated, e.g. :he instead of :help.")
commands foreach { cmd =>
echo(formatStr.format(cmd.usageMsg, cmd.help))
}
}
private def ambiguousError(cmd: String): Result = {
matchingCommands(cmd) match {
case Nil => echo(cmd + ": no such command. Type :help for help.")
case xs => echo(cmd + " is ambiguous: did you mean " + xs.map(":" + _.name).mkString(" or ") + "?")
}
Result(keepRunning = true, None)
}
private def matchingCommands(cmd: String) = commands filter (_.name startsWith cmd)
private def uniqueCommand(cmd: String): Option[LoopCommand] = {
// this lets us add commands willy-nilly and only requires enough command to disambiguate
matchingCommands(cmd) match {
case List(x) => Some(x)
// exact match OK even if otherwise appears ambiguous
case xs => xs find (_.name == cmd)
}
}
/** Show the history */
lazy val historyCommand = new LoopCommand("history", "show the history (optional num is commands to show)") {
override def usage = "[num]"
def defaultLines = 20
def apply(line: String): Result = {
if (history eq NoHistory)
return "No history available."
val xs = words(line)
val current = history.index
val count = try xs.head.toInt catch { case _: Exception => defaultLines }
val lines = history.asStrings takeRight count
val offset = current - lines.size + 1
for ((line, index) <- lines.zipWithIndex)
echo("%3d %s".format(index + offset, line))
}
}
// When you know you are most likely breaking into the middle
// of a line being typed. This softens the blow.
protected def echoAndRefresh(msg: String) = {
echo("\n" + msg)
in.redrawLine()
}
protected def echo(msg: String) = {
out println msg
out.flush()
}
/** Search the history */
def searchHistory(_cmdline: String) {
val cmdline = _cmdline.toLowerCase
val offset = history.index - history.size + 1
for ((line, index) <- history.asStrings.zipWithIndex ; if line.toLowerCase contains cmdline)
echo("%d %s".format(index + offset, line))
}
private val currentPrompt = Properties.shellPromptString
/** Prompt to print when awaiting input */
def prompt = currentPrompt
import LoopCommand.{ cmd, nullary }
/** Standard commands **/
lazy val standardCommands = List(
cmd("cp", "<path>", "add a jar or directory to the classpath", addClasspath),
cmd("edit", "<id>|<line>", "edit history", editCommand),
cmd("help", "[command]", "print this summary or command-specific help", helpCommand),
historyCommand,
cmd("h?", "<string>", "search the history", searchHistory),
cmd("imports", "[name name ...]", "show import history, identifying sources of names", importsCommand),
cmd("implicits", "[-v]", "show the implicits in scope", intp.implicitsCommand),
cmd("javap", "<path|class>", "disassemble a file or class name", javapCommand),
cmd("line", "<id>|<line>", "place line(s) at the end of history", lineCommand),
cmd("load", "<path>", "interpret lines in a file", loadCommand),
cmd("paste", "[-raw] [path]", "enter paste mode or paste a file", pasteCommand),
nullary("power", "enable power user mode", powerCmd),
nullary("quit", "exit the interpreter", () => Result(keepRunning = false, None)),
nullary("replay", "reset execution and replay all previous commands", replay),
nullary("reset", "reset the repl to its initial state, forgetting all session entries", resetCommand),
cmd("save", "<path>", "save replayable session to a file", saveCommand),
shCommand,
cmd("settings", "[+|-]<options>", "+enable/-disable flags, set compiler options", changeSettings),
nullary("silent", "disable/enable automatic printing of results", verbosity),
cmd("type", "[-v] <expr>", "display the type of an expression without evaluating it", typeCommand),
cmd("kind", "[-v] <expr>", "display the kind of expression's type", kindCommand),
nullary("warnings", "show the suppressed warnings from the most recent line which had any", warningsCommand)
)
/** Power user commands */
lazy val powerCommands: List[LoopCommand] = List(
cmd("phase", "<phase>", "set the implicit phase for power commands", phaseCommand)
)
private def importsCommand(line: String): Result = {
val tokens = words(line)
val handlers = intp.languageWildcardHandlers ++ intp.importHandlers
handlers.filterNot(_.importedSymbols.isEmpty).zipWithIndex foreach {
case (handler, idx) =>
val (types, terms) = handler.importedSymbols partition (_.name.isTypeName)
val imps = handler.implicitSymbols
val found = tokens filter (handler importsSymbolNamed _)
val typeMsg = if (types.isEmpty) "" else types.size + " types"
val termMsg = if (terms.isEmpty) "" else terms.size + " terms"
val implicitMsg = if (imps.isEmpty) "" else imps.size + " are implicit"
val foundMsg = if (found.isEmpty) "" else found.mkString(" // imports: ", ", ", "")
val statsMsg = List(typeMsg, termMsg, implicitMsg) filterNot (_ == "") mkString ("(", ", ", ")")
intp.reporter.printMessage("%2d) %-30s %s%s".format(
idx + 1,
handler.importString,
statsMsg,
foundMsg
))
}
}
private def findToolsJar() = PathResolver.SupplementalLocations.platformTools
private def addToolsJarToLoader() = {
val cl = findToolsJar() match {
case Some(tools) => ScalaClassLoader.fromURLs(Seq(tools.toURL), intp.classLoader)
case _ => intp.classLoader
}
if (Javap.isAvailable(cl)) {
repldbg(":javap available.")
cl
}
else {
repldbg(":javap unavailable: no tools.jar at " + jdkHome)
intp.classLoader
}
}
protected def newJavap() =
JavapClass(addToolsJarToLoader(), new IMain.ReplStrippingWriter(intp), Some(intp))
private lazy val javap = substituteAndLog[Javap]("javap", NoJavap)(newJavap())
// Still todo: modules.
private def typeCommand(line0: String): Result = {
line0.trim match {
case "" => ":type [-v] <expression>"
case s => intp.typeCommandInternal(s stripPrefix "-v " trim, verbose = s startsWith "-v ")
}
}
private def kindCommand(expr: String): Result = {
expr.trim match {
case "" => ":kind [-v] <expression>"
case s => intp.kindCommandInternal(s stripPrefix "-v " trim, verbose = s startsWith "-v ")
}
}
private def warningsCommand(): Result = {
if (intp.lastWarnings.isEmpty)
"Can't find any cached warnings."
else
intp.lastWarnings foreach { case (pos, msg) => intp.reporter.warning(pos, msg) }
}
private def changeSettings(args: String): Result = {
def showSettings() = {
for (s <- settings.userSetSettings.toSeq.sorted) echo(s.toString)
}
def updateSettings() = {
// put aside +flag options
val (pluses, rest) = (args split "\\s+").toList partition (_.startsWith("+"))
val tmps = new Settings
val (ok, leftover) = tmps.processArguments(rest, processAll = true)
if (!ok) echo("Bad settings request.")
else if (leftover.nonEmpty) echo("Unprocessed settings.")
else {
// boolean flags set-by-user on tmp copy should be off, not on
val offs = tmps.userSetSettings filter (_.isInstanceOf[Settings#BooleanSetting])
val (minuses, nonbools) = rest partition (arg => offs exists (_ respondsTo arg))
// update non-flags
settings.processArguments(nonbools, processAll = true)
// also snag multi-value options for clearing, e.g. -Ylog: and -language:
for {
s <- settings.userSetSettings
if s.isInstanceOf[Settings#MultiStringSetting] || s.isInstanceOf[Settings#PhasesSetting]
if nonbools exists (arg => arg.head == '-' && arg.last == ':' && (s respondsTo arg.init))
} s match {
case c: Clearable => c.clear()
case _ =>
}
def update(bs: Seq[String], name: String=>String, setter: Settings#Setting=>Unit) = {
for (b <- bs)
settings.lookupSetting(name(b)) match {
case Some(s) =>
if (s.isInstanceOf[Settings#BooleanSetting]) setter(s)
else echo(s"Not a boolean flag: $b")
case _ =>
echo(s"Not an option: $b")
}
}
update(minuses, identity, _.tryToSetFromPropertyValue("false")) // turn off
update(pluses, "-" + _.drop(1), _.tryToSet(Nil)) // turn on
}
}
if (args.isEmpty) showSettings() else updateSettings()
}
private def javapCommand(line: String): Result = {
if (javap == null)
":javap unavailable, no tools.jar at %s. Set JDK_HOME.".format(jdkHome)
else if (line == "")
":javap [-lcsvp] [path1 path2 ...]"
else
javap(words(line)) foreach { res =>
if (res.isError) return "Failed: " + res.value
else res.show()
}
}
private def pathToPhaseWrapper = intp.originalPath("$r") + ".phased.atCurrent"
private def phaseCommand(name: String): Result = {
val phased: Phased = power.phased
import phased.NoPhaseName
if (name == "clear") {
phased.set(NoPhaseName)
intp.clearExecutionWrapper()
"Cleared active phase."
}
else if (name == "") phased.get match {
case NoPhaseName => "Usage: :phase <expr> (e.g. typer, erasure.next, erasure+3)"
case ph => "Active phase is '%s'. (To clear, :phase clear)".format(phased.get)
}
else {
val what = phased.parse(name)
if (what.isEmpty || !phased.set(what))
"'" + name + "' does not appear to represent a valid phase."
else {
intp.setExecutionWrapper(pathToPhaseWrapper)
val activeMessage =
if (what.toString.length == name.length) "" + what
else "%s (%s)".format(what, name)
"Active phase is now: " + activeMessage
}
}
}
/** Available commands */
def commands: List[LoopCommand] = standardCommands ++ (
if (isReplPower) powerCommands else Nil
)
val replayQuestionMessage =
"""|That entry seems to have slain the compiler. Shall I replay
|your session? I can re-run each line except the last one.
|[y/n]
""".trim.stripMargin
private val crashRecovery: PartialFunction[Throwable, Boolean] = {
case ex: Throwable =>
val (err, explain) = (
if (intp.isInitializeComplete)
(intp.global.throwableAsString(ex), "")
else
(ex.getMessage, "The compiler did not initialize.\n")
)
echo(err)
ex match {
case _: NoSuchMethodError | _: NoClassDefFoundError =>
echo("\nUnrecoverable error.")
throw ex
case _ =>
def fn(): Boolean =
try in.readYesOrNo(explain + replayQuestionMessage, { echo("\nYou must enter y or n.") ; fn() })
catch { case _: RuntimeException => false }
if (fn()) replay()
else echo("\nAbandoning crashed session.")
}
true
}
// return false if repl should exit
def processLine(line: String): Boolean = {
import scala.concurrent.duration._
Await.ready(globalFuture, 60.seconds)
(line ne null) && (command(line) match {
case Result(false, _) => false
case Result(_, Some(line)) => addReplay(line) ; true
case _ => true
})
}
private def readOneLine() = {
out.flush()
in readLine prompt
}
/** The main read-eval-print loop for the repl. It calls
* command() for each line of input, and stops when
* command() returns false.
*/
@tailrec final def loop() {
if ( try processLine(readOneLine()) catch crashRecovery )
loop()
}
/** interpret all lines from a specified file */
def interpretAllFrom(file: File) {
savingReader {
savingReplayStack {
file applyReader { reader =>
in = SimpleReader(reader, out, interactive = false)
echo("Loading " + file + "...")
loop()
}
}
}
}
/** create a new interpreter and replay the given commands */
def replay() {
reset()
if (replayCommandStack.isEmpty)
echo("Nothing to replay.")
else for (cmd <- replayCommands) {
echo("Replaying: " + cmd) // flush because maybe cmd will have its own output
command(cmd)
echo("")
}
}
def resetCommand() {
echo("Resetting interpreter state.")
if (replayCommandStack.nonEmpty) {
echo("Forgetting this session history:\n")
replayCommands foreach echo
echo("")
replayCommandStack = Nil
}
if (intp.namedDefinedTerms.nonEmpty)
echo("Forgetting all expression results and named terms: " + intp.namedDefinedTerms.mkString(", "))
if (intp.definedTypes.nonEmpty)
echo("Forgetting defined types: " + intp.definedTypes.mkString(", "))
reset()
}
def reset() {
intp.reset()
unleashAndSetPhase()
}
def lineCommand(what: String): Result = editCommand(what, None)
// :edit id or :edit line
def editCommand(what: String): Result = editCommand(what, Properties.envOrNone("EDITOR"))
def editCommand(what: String, editor: Option[String]): Result = {
def diagnose(code: String) = {
echo("The edited code is incomplete!\n")
val errless = intp compileSources new BatchSourceFile("<pastie>", s"object pastel {\n$code\n}")
if (errless) echo("The compiler reports no errors.")
}
def historicize(text: String) = history match {
case jlh: JLineHistory => text.lines foreach jlh.add ; jlh.moveToEnd() ; true
case _ => false
}
def edit(text: String): Result = editor match {
case Some(ed) =>
val tmp = File.makeTemp()
tmp.writeAll(text)
try {
val pr = new ProcessResult(s"$ed ${tmp.path}")
pr.exitCode match {
case 0 =>
tmp.safeSlurp() match {
case Some(edited) if edited.trim.isEmpty => echo("Edited text is empty.")
case Some(edited) =>
echo(edited.lines map ("+" + _) mkString "\n")
val res = intp interpret edited
if (res == IR.Incomplete) diagnose(edited)
else {
historicize(edited)
Result(lineToRecord = Some(edited), keepRunning = true)
}
case None => echo("Can't read edited text. Did you delete it?")
}
case x => echo(s"Error exit from $ed ($x), ignoring")
}
} finally {
tmp.delete()
}
case None =>
if (historicize(text)) echo("Placing text in recent history.")
else echo(f"No EDITOR defined and you can't change history, echoing your text:%n$text")
}
// if what is a number, use it as a line number or range in history
def isNum = what forall (c => c.isDigit || c == '-' || c == '+')
// except that "-" means last value
def isLast = (what == "-")
if (isLast || !isNum) {
val name = if (isLast) intp.mostRecentVar else what
val sym = intp.symbolOfIdent(name)
intp.prevRequestList collectFirst { case r if r.defines contains sym => r } match {
case Some(req) => edit(req.line)
case None => echo(s"No symbol in scope: $what")
}
} else try {
val s = what
// line 123, 120+3, -3, 120-123, 120-, note -3 is not 0-3 but (cur-3,cur)
val (start, len) =
if ((s indexOf '+') > 0) {
val (a,b) = s splitAt (s indexOf '+')
(a.toInt, b.drop(1).toInt)
} else {
(s indexOf '-') match {
case -1 => (s.toInt, 1)
case 0 => val n = s.drop(1).toInt ; (history.index - n, n)
case _ if s.last == '-' => val n = s.init.toInt ; (n, history.index - n)
case i => val n = s.take(i).toInt ; (n, s.drop(i+1).toInt - n)
}
}
import scala.collection.JavaConverters._
val index = (start - 1) max 0
val text = history match {
case jlh: JLineHistory => jlh.entries(index).asScala.take(len) map (_.value) mkString "\n"
case _ => history.asStrings.slice(index, index + len) mkString "\n"
}
edit(text)
} catch {
case _: NumberFormatException => echo(s"Bad range '$what'")
echo("Use line 123, 120+3, -3, 120-123, 120-, note -3 is not 0-3 but (cur-3,cur)")
}
}
/** fork a shell and run a command */
lazy val shCommand = new LoopCommand("sh", "run a shell command (result is implicitly => List[String])") {
override def usage = "<command line>"
def apply(line: String): Result = line match {
case "" => showUsage()
case _ =>
val toRun = s"new ${classOf[ProcessResult].getName}(${string2codeQuoted(line)})"
intp interpret toRun
()
}
}
def withFile[A](filename: String)(action: File => A): Option[A] = {
val res = Some(File(filename)) filter (_.exists) map action
if (res.isEmpty) echo("That file does not exist") // courtesy side-effect
res
}
def loadCommand(arg: String) = {
var shouldReplay: Option[String] = None
withFile(arg)(f => {
interpretAllFrom(f)
shouldReplay = Some(":load " + arg)
})
Result(keepRunning = true, shouldReplay)
}
def saveCommand(filename: String): Result = (
if (filename.isEmpty) echo("File name is required.")
else if (replayCommandStack.isEmpty) echo("No replay commands in session")
else File(filename).printlnAll(replayCommands: _*)
)
def addClasspath(arg: String): Unit = {
val f = File(arg).normalize
if (f.exists) {
addedClasspath = ClassPath.join(addedClasspath, f.path)
val totalClasspath = ClassPath.join(settings.classpath.value, addedClasspath)
echo("Added '%s'. Your new classpath is:\n\"%s\"".format(f.path, totalClasspath))
replay()
}
else echo("The path '" + f + "' doesn't seem to exist.")
}
def powerCmd(): Result = {
if (isReplPower) "Already in power mode."
else enablePowerMode(isDuringInit = false)
}
def enablePowerMode(isDuringInit: Boolean) = {
replProps.power setValue true
unleashAndSetPhase()
asyncEcho(isDuringInit, power.banner)
}
private def unleashAndSetPhase() {
if (isReplPower) {
power.unleash()
// Set the phase to "typer"
intp beSilentDuring phaseCommand("typer")
}
}
def asyncEcho(async: Boolean, msg: => String) {
if (async) asyncMessage(msg)
else echo(msg)
}
def verbosity() = {
val old = intp.printResults
intp.printResults = !old
echo("Switched " + (if (old) "off" else "on") + " result printing.")
}
/** Run one command submitted by the user. Two values are returned:
* (1) whether to keep running, (2) the line to record for replay,
* if any. */
def command(line: String): Result = {
if (line startsWith ":") {
val cmd = line.tail takeWhile (x => !x.isWhitespace)
uniqueCommand(cmd) match {
case Some(lc) => lc(line.tail stripPrefix cmd dropWhile (_.isWhitespace))
case _ => ambiguousError(cmd)
}
}
else if (intp.global == null) Result(keepRunning = false, None) // Notice failure to create compiler
else Result(keepRunning = true, interpretStartingWith(line))
}
private def readWhile(cond: String => Boolean) = {
Iterator continually in.readLine("") takeWhile (x => x != null && cond(x))
}
def pasteCommand(arg: String): Result = {
var shouldReplay: Option[String] = None
def result = Result(keepRunning = true, shouldReplay)
val (raw, file) =
if (arg.isEmpty) (false, None)
else {
val r = """(-raw)?(\s+)?([^\-]\S*)?""".r
arg match {
case r(flag, sep, name) =>
if (flag != null && name != null && sep == null)
echo(s"""I assume you mean "$flag $name"?""")
(flag != null, Option(name))
case _ =>
echo("usage: :paste -raw file")
return result
}
}
val code = file match {
case Some(name) =>
withFile(name)(f => {
shouldReplay = Some(s":paste $arg")
val s = f.slurp.trim
if (s.isEmpty) echo(s"File contains no code: $f")
else echo(s"Pasting file $f...")
s
}) getOrElse ""
case None =>
echo("// Entering paste mode (ctrl-D to finish)\n")
val text = (readWhile(_ => true) mkString "\n").trim
if (text.isEmpty) echo("\n// Nothing pasted, nothing gained.\n")
else echo("\n// Exiting paste mode, now interpreting.\n")
text
}
def interpretCode() = {
val res = intp interpret code
// if input is incomplete, let the compiler try to say why
if (res == IR.Incomplete) {
echo("The pasted code is incomplete!\n")
// Remembrance of Things Pasted in an object
val errless = intp compileSources new BatchSourceFile("<pastie>", s"object pastel {\n$code\n}")
if (errless) echo("...but compilation found no error? Good luck with that.")
}
}
def compileCode() = {
val errless = intp compileSources new BatchSourceFile("<pastie>", code)
if (!errless) echo("There were compilation errors!")
}
if (code.nonEmpty) {
if (raw) compileCode() else interpretCode()
}
result
}
private object paste extends Pasted {
val ContinueString = " | "
val PromptString = "scala> "
def interpret(line: String): Unit = {
echo(line.trim)
intp interpret line
echo("")
}
def transcript(start: String) = {
echo("\n// Detected repl transcript paste: ctrl-D to finish.\n")
apply(Iterator(start) ++ readWhile(_.trim != PromptString.trim))
}
}
import paste.{ ContinueString, PromptString }
/** Interpret expressions starting with the first line.
* Read lines until a complete compilation unit is available
* or until a syntax error has been seen. If a full unit is
* read, go ahead and interpret it. Return the full string
* to be recorded for replay, if any.
*/
def interpretStartingWith(code: String): Option[String] = {
// signal completion non-completion input has been received
in.completion.resetVerbosity()
def reallyInterpret = {
val reallyResult = intp.interpret(code)
(reallyResult, reallyResult match {
case IR.Error => None
case IR.Success => Some(code)
case IR.Incomplete =>
if (in.interactive && code.endsWith("\n\n")) {
echo("You typed two blank lines. Starting a new command.")
None
}
else in.readLine(ContinueString) match {
case null =>
// we know compilation is going to fail since we're at EOF and the
// parser thinks the input is still incomplete, but since this is
// a file being read non-interactively we want to fail. So we send
// it straight to the compiler for the nice error message.
intp.compileString(code)
None
case line => interpretStartingWith(code + "\n" + line)
}
})
}
/** Here we place ourselves between the user and the interpreter and examine
* the input they are ostensibly submitting. We intervene in several cases:
*
* 1) If the line starts with "scala> " it is assumed to be an interpreter paste.
* 2) If the line starts with "." (but not ".." or "./") it is treated as an invocation
* on the previous result.
* 3) If the Completion object's execute returns Some(_), we inject that value
* and avoid the interpreter, as it's likely not valid scala code.
*/
if (code == "") None
else if (!paste.running && code.trim.startsWith(PromptString)) {
paste.transcript(code)
None
}
else if (Completion.looksLikeInvocation(code) && intp.mostRecentVar != "") {
interpretStartingWith(intp.mostRecentVar + code)
}
else if (code.trim startsWith "//") {
// line comment, do nothing
None
}
else
reallyInterpret._2
}
// runs :load `file` on any files passed via -i
def loadFiles(settings: Settings) = settings match {
case settings: GenericRunnerSettings =>
for (filename <- settings.loadfiles.value) {
val cmd = ":load " + filename
command(cmd)
addReplay(cmd)
echo("")
}
case _ =>
}
/** Tries to create a JLineReader, falling back to SimpleReader:
* unless settings or properties are such that it should start
* with SimpleReader.
*/
def chooseReader(settings: Settings): InteractiveReader = {
if (settings.Xnojline || Properties.isEmacsShell)
SimpleReader()
else try new JLineReader(
if (settings.noCompletion) NoCompletion
else new JLineCompletion(intp)
)
catch {
case ex @ (_: Exception | _: NoClassDefFoundError) =>
echo("Failed to created JLineReader: " + ex + "\nFalling back to SimpleReader.")
SimpleReader()
}
}
private def loopPostInit() {
// Bind intp somewhere out of the regular namespace where
// we can get at it in generated code.
intp.quietBind(NamedParam[IMain]("$intp", intp)(tagOfIMain, classTag[IMain]))
// Auto-run code via some setting.
( replProps.replAutorunCode.option
flatMap (f => io.File(f).safeSlurp())
foreach (intp quietRun _)
)
// classloader and power mode setup
intp.setContextClassLoader()
if (isReplPower) {
replProps.power setValue true
unleashAndSetPhase()
asyncMessage(power.banner)
}
// SI-7418 Now, and only now, can we enable TAB completion.
in match {
case x: JLineReader => x.consoleReader.postInit
case _ =>
}
}
def process(settings: Settings): Boolean = savingContextLoader {
this.settings = settings
createInterpreter()
// sets in to some kind of reader depending on environmental cues
in = in0.fold(chooseReader(settings))(r => SimpleReader(r, out, interactive = true))
globalFuture = future {
intp.initializeSynchronous()
loopPostInit()
!intp.reporter.hasErrors
}
loadFiles(settings)
printWelcome()
try loop()
catch AbstractOrMissingHandler()
finally closeInterpreter()
true
}
@deprecated("Use `process` instead", "2.9.0")
def main(settings: Settings): Unit = process(settings) //used by sbt
}
object ILoop {
implicit def loopToInterpreter(repl: ILoop): IMain = repl.intp
// Designed primarily for use by test code: take a String with a
// bunch of code, and prints out a transcript of what it would look
// like if you'd just typed it into the repl.
def runForTranscript(code: String, settings: Settings): String = {
import java.io.{ BufferedReader, StringReader, OutputStreamWriter }
stringFromStream { ostream =>
Console.withOut(ostream) {
val output = new JPrintWriter(new OutputStreamWriter(ostream), true) {
override def write(str: String) = {
// completely skip continuation lines
if (str forall (ch => ch.isWhitespace || ch == '|')) ()
else super.write(str)
}
}
val input = new BufferedReader(new StringReader(code.trim + "\n")) {
override def readLine(): String = {
val s = super.readLine()
// helping out by printing the line being interpreted.
if (s != null)
output.println(s)
s
}
}
val repl = new ILoop(input, output)
if (settings.classpath.isDefault)
settings.classpath.value = sys.props("java.class.path")
repl process settings
}
}
}
/** Creates an interpreter loop with default settings and feeds
* the given code to it as input.
*/
def run(code: String, sets: Settings = new Settings): String = {
import java.io.{ BufferedReader, StringReader, OutputStreamWriter }
stringFromStream { ostream =>
Console.withOut(ostream) {
val input = new BufferedReader(new StringReader(code))
val output = new JPrintWriter(new OutputStreamWriter(ostream), true)
val repl = new ILoop(input, output)
if (sets.classpath.isDefault)
sets.classpath.value = sys.props("java.class.path")
repl process sets
}
}
}
def run(lines: List[String]): String = run(lines map (_ + "\n") mkString)
}
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