REPL: JLine 3: fix various issues

src/repl-frontend/scala/tools/nsc/interpreter/jline/Reader.scala

@@ -32,17 +32,23 @@ class Reader private (
     terminal: Terminal) extends shell.InteractiveReader {
   override val history: shell.History = new HistoryAdaptor(reader.getHistory)
   override def interactive: Boolean = true
-  protected def readOneKey(prompt: String): Int = ???
   protected def readOneLine(prompt: String): String = {
     try {
       reader.readLine(prompt)
     } catch {
       case _: EndOfFileException | _: UserInterruptException => reader.getBuffer.delete() ; null
     }
   }
-  override def redrawLine(): Unit = ???
-  override def reset(): Unit = accumulator.reset()
+  def redrawLine(): Unit = ???
+  def reset(): Unit = accumulator.reset()
   override def close(): Unit = terminal.close()
+
+  override def withSecondaryPrompt[T](prompt: String)(body: => T): T = {
+    val oldPrompt = reader.getVariable(LineReader.SECONDARY_PROMPT_PATTERN)
+    reader.setVariable(LineReader.SECONDARY_PROMPT_PATTERN, prompt)
+    try body
+    finally reader.setVariable(LineReader.SECONDARY_PROMPT_PATTERN, oldPrompt)
+  }
 }
 
 object Reader {
@@ -148,13 +154,14 @@ object Reader {
     }
     def tokenize(line: String, cursor: Int): ScalaParsedLine = {
       val tokens = repl.tokenize(line)
-      //println(s"Got ${tokens.size} tokens")
-      if (tokens.isEmpty) ScalaParsedLine(line, cursor, 0, 0, List(TokenData(0,0,0)))
+      if (tokens.isEmpty) ScalaParsedLine(line, cursor, 0, 0, Nil)
       else {
         val current = tokens.find(t => t.start <= cursor && cursor <= t.end)
         val (wordCursor, wordIndex) = current match {
-          case Some(t) => (cursor - t.start, tokens.indexOf(t))
-          case _ => (tokens.last.end - tokens.last.start, tokens.size - 1)
+          case Some(t) if t.isIdentifier =>
+            (cursor - t.start, tokens.indexOf(t))
+          case _ =>
+            (0, -1)
         }
         ScalaParsedLine(line, cursor, wordCursor, wordIndex, tokens)
       }
@@ -172,25 +179,26 @@ object Reader {
    * @param line the line
    */
   case class ScalaParsedLine(line: String, cursor: Int, wordCursor: Int, wordIndex: Int, tokens: List[TokenData]) extends CompletingParsedLine {
-    require(wordIndex < tokens.size, s"wordIndex $wordIndex out of range ${tokens.size}")
-    require(wordCursor <= tokens(wordIndex).end - tokens(wordIndex).start, s"wordCursor $wordCursor should be in range ${tokens(wordIndex)}")
+    require(wordIndex <= tokens.size,
+      s"wordIndex $wordIndex out of range ${tokens.size}")
+    require(wordIndex == -1 || wordCursor == 0 || wordCursor <= tokens(wordIndex).end - tokens(wordIndex).start,
+      s"wordCursor $wordCursor should be in range ${tokens(wordIndex)}")
     // Members declared in org.jline.reader.CompletingParsedLine.
     // This is where backticks could be added, for example.
     def escape(candidate: CharSequence, complete: Boolean): CharSequence = candidate
     def rawWordCursor: Int = wordCursor
     def rawWordLength: Int = word.length
-
-    // Members declared in org.jline.reader.ParsedLine
-    //def cursor(): Int = ???
-    //def line(): String = ???
-    def word: String = {
-      val t = tokens(wordIndex)
-      line.substring(t.start, t.end)
+    def word: String =
+      if (wordIndex == -1 || wordIndex == tokens.size)
+        ""
+      else {
+        val t = tokens(wordIndex)
+        line.substring(t.start, t.end)
+      }
+    def words: JList[String] = {
+      import scala.jdk.CollectionConverters._
+      tokens.map(t => line.substring(t.start, t.end)).asJava
     }
-    //def wordCursor: Int = 0  // offset in current word
-    //def wordIndex: Int = 0   // index of current word in tokens
-    import scala.jdk.CollectionConverters._
-    def words: JList[String] = tokens.map(t => line.substring(t.start, t.end)).asJava
   }
 
   private def initLogging(): Unit = {
@@ -226,8 +234,24 @@ class Completion(delegate: shell.Completion) extends shell.Completion with Compl
       new Candidate(value, displayed, group, descr, suffix, key, complete)
     }
     val result = complete(parsedLine.line, parsedLine.cursor)
-    //Console.err.println(s"completing $parsedLine to ${result.candidates}")
-    for (s <- result.candidates) newCandidates.add(candidateForResult(s))
+    result.candidates match {
+      // the presence of the empty string here is a signal that the symbol
+      // is already complete and so instead of completing, we want to show
+      // the user the method signature. there are various JLine 3 features
+      // one might use to do this instead; sticking to basics for now
+      case "" :: defStrings if defStrings.nonEmpty =>
+        // specifics here are cargo-culted from Ammonite
+        lineReader.getTerminal.writer.println()
+        for (s <- defStrings)
+          lineReader.getTerminal.writer.println(s)
+        lineReader.callWidget(LineReader.REDRAW_LINE)
+        lineReader.callWidget(LineReader.REDISPLAY)
+        lineReader.getTerminal.flush()
+      // normal completion
+      case cs =>
+        for (s <- result.candidates)
+          newCandidates.add(candidateForResult(s))
+    }
   }
 }
 

src/repl-frontend/scala/tools/nsc/interpreter/shell/ILoop.scala

@@ -801,17 +801,19 @@ class ILoop(config: ShellConfig, inOverride: BufferedReader = null,
         } getOrElse ""
       case (eof, _) =>
         echo(s"// Entering paste mode (${ eof getOrElse "ctrl-D" } to finish)\n")
-        val delimiter = eof orElse config.pasteDelimiter.option
-        val input = readWhile(s => delimiter.isEmpty || delimiter.get != s) mkString "\n"
-        val text = (
-          margin filter (_.nonEmpty) map {
-            case "-" => input.linesIterator map (_.trim) mkString "\n"
-            case m   => input stripMargin m.head   // ignore excess chars in "<<||"
-          } getOrElse input
-        ).trim
-        if (text.isEmpty) echo("\n// Nothing pasted, nothing gained.\n")
-        else echo("\n// Exiting paste mode, now interpreting.\n")
-        text
+        in.withSecondaryPrompt("") {
+          val delimiter = eof orElse config.pasteDelimiter.option
+          val input = readWhile(s => delimiter.isEmpty || delimiter.get != s) mkString "\n"
+          val text = (
+            margin filter (_.nonEmpty) map {
+              case "-" => input.linesIterator map (_.trim) mkString "\n"
+              case m => input stripMargin m.head // ignore excess chars in "<<||"
+            } getOrElse input
+            ).trim
+          if (text.isEmpty) echo("\n// Nothing pasted, nothing gained.\n")
+          else echo("\n// Exiting paste mode, now interpreting.\n")
+          text
+        }
     }
     def interpretCode() = {
       if (intp.withLabel(label)(intp interpret code) == Incomplete)

src/repl-frontend/scala/tools/nsc/interpreter/shell/InteractiveReader.scala

@@ -24,16 +24,16 @@ trait InteractiveReader {
   def history: History
   def completion: Completion
   def redrawLine(): Unit
+  def withSecondaryPrompt[T](prompt: String)(body: => T): T = body
 
-  def readYesOrNo(prompt: String, alt: => Boolean): Boolean = readOneKey(prompt) match {
-    case 'y'  => true
-    case 'n'  => false
-    case -1   => false // EOF
-    case _    => alt
-  }
+  def readYesOrNo(prompt: String, alt: => Boolean): Boolean =
+    readOneLine(prompt).trim.toUpperCase.headOption match {
+      case Some('Y') => true
+      case Some('N') => false
+      case _ => alt
+    }
 
   protected def readOneLine(prompt: String): String
-  protected def readOneKey(prompt: String): Int
 
   def readLine(prompt: String): String = readOneLine(prompt)
     /*

src/repl-frontend/scala/tools/nsc/interpreter/shell/ReplCompletion.scala

@@ -22,17 +22,17 @@ class ReplCompletion(intp: Repl, val accumulator: Accumulator = new Accumulator)
   import ReplCompletion._
 
   def complete(buffer: String, cursor: Int): CompletionResult = {
-      // special case for:
-      //
-      // scala> 1
-      // scala> .toInt
-      val bufferWithVar =
-        if (Parsed.looksLikeInvocation(buffer)) intp.mostRecentVar + buffer
-        else buffer
+    // special case for:
+    //
+    // scala> 1
+    // scala> .toInt
+    val bufferWithVar =
+      if (Parsed.looksLikeInvocation(buffer)) intp.mostRecentVar + buffer
+      else buffer
 
-      val bufferWithMultiLine = accumulator.toString + bufferWithVar
-      val cursor1 = cursor + (bufferWithMultiLine.length - buffer.length)
-      codeCompletion(bufferWithMultiLine, cursor1)
+    val bufferWithMultiLine = accumulator.toString + bufferWithVar
+    val cursor1 = cursor + (bufferWithMultiLine.length - buffer.length)
+    codeCompletion(bufferWithMultiLine, cursor1)
   }
 
   private var lastRequest = NoRequest

src/repl-frontend/scala/tools/nsc/interpreter/shell/SimpleReader.scala

@@ -35,8 +35,6 @@ class SimpleReader(in: BufferedReader, out: JPrintWriter, val completion: Comple
     input
   }
 
-  protected def readOneKey(prompt: String) = throw new IllegalStateException("No char-based input in SimpleReader")
-
   protected def readOneLine(): String = in.readLine()
   protected def echo(s: String): Unit = if (interactive) {
     out.print(s)

src/repl/scala/tools/nsc/interpreter/IMain.scala

@@ -465,7 +465,10 @@ class IMain(val settings: Settings, parentClassLoaderOverride: Option[ClassLoade
   }
 
   // parseStats, returning status but no trees
-  def parseString(line: String): Result = parse(line).fold(e => e, _ => Success)
+  def parseString(line: String): Result =
+    reporter.suppressOutput {
+      parse(line).fold(e => e, _ => Success)
+    }
 
   def tokenize(line: String): List[TokenData] = {
     import collection.mutable.ListBuffer
@@ -479,8 +482,9 @@ class IMain(val settings: Settings, parentClassLoaderOverride: Option[ClassLoade
       u.nextToken()
     }
     b += u.lastOffset
+    import scala.tools.nsc.ast.parser.Tokens.isIdentifier
     b.drop(1).grouped(3).flatMap(triple => triple.toList match {
-      case List(token, start, end) => Some(TokenData(token, start, end))
+      case List(token, start, end) => Some(TokenData(token, start, end, isIdentifier(token)))
       case _ => println(s"Skipping token ${scala.runtime.ScalaRunTime.stringOf(triple)}") ; None
     }).toList
   }

src/repl/scala/tools/nsc/interpreter/Interface.scala

@@ -322,4 +322,4 @@ trait PresentationCompilationResult {
   def candidates(tabCount: Int): (Int, List[String])
 }
 
-case class TokenData(token: Int, start: Int, end: Int)
+case class TokenData(token: Int, start: Int, end: Int, isIdentifier: Boolean)

test/files/run/repl-previous-result.check

@@ -0,0 +1,8 @@
+
+scala> "foobar"
+val res0: String = foobar
+
+scala> .size
+val res1: Int = 6
+
+scala> :quit

test/files/run/repl-previous-result.scala

@@ -0,0 +1,8 @@
+import scala.tools.partest.ReplTest
+
+object Test extends ReplTest {
+  override def code = """
+    |"foobar"
+    |.size
+  """.stripMargin.trim
+}