Fix completion of keywored-starting-idents (e.g. formatted) and add CTRL-T type/tree printer

Author: retronym

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

@@ -13,15 +13,21 @@
 package scala.tools.nsc.interpreter
 package jline
 
-import java.util.{List => JList}
-import org.jline.reader.{Candidate, Completer, CompletingParsedLine, EOFError, EndOfFileException, History, LineReader, ParsedLine, Parser, SyntaxError, UserInterruptException}
+import java.util.{Collections, List => JList}
+import org.jline.reader.{Candidate, Completer, CompletingParsedLine, EOFError, EndOfFileException, History, LineReader, ParsedLine, Parser, Reference, SyntaxError, UserInterruptException}
 import org.jline.reader.impl.{CompletionMatcherImpl, DefaultParser, LineReaderImpl}
 import org.jline.terminal.Terminal
 
 import shell.{Accumulator, ShellConfig}
 import Parser.ParseContext
+import org.jline.console.{CmdDesc, CmdLine}
+import org.jline.keymap.KeyMap
+import org.jline.utils.AttributedString
+import org.jline.widget.TailTipWidgets.TipType
+import org.jline.widget.{TailTipWidgets}
 
 import java.{lang, util}
+import scala.reflect.internal.Chars
 
 /** A Reader that delegates to JLine3.
  */
@@ -95,21 +101,67 @@ object Reader {
         .option(Option.DISABLE_EVENT_EXPANSION, true) // Otherwise `scala> println(raw"\n".toList)` gives `List(n)` !!
         .option(Option.COMPLETE_MATCHER_CAMELCASE, true)
     }
-    builder.completionMatcher(new CompletionMatcherImpl {
+    object customCompletionMatcher extends CompletionMatcherImpl {
       override def compile(options: util.Map[LineReader.Option, lang.Boolean], prefix: Boolean, line: CompletingParsedLine, caseInsensitive: Boolean, errors: Int, originalGroupName: String): Unit = {
         super.compile(options, prefix, line, caseInsensitive, errors, originalGroupName)
         // TODO Use Option.COMPLETION_MATCHER_TYPO(false) in once https://github.com/jline/jline3/pull/646
         matchers.remove(matchers.size() - 2)
-        // TODO add SNAKE_CASE completion matcher.
       }
-    })
+
+      override def matches(candidates: JList[Candidate]): JList[Candidate] = {
+        val matching = super.matches(candidates)
+        matching
+      }
+    }
+
+    builder.completionMatcher(customCompletionMatcher)
 
     val reader = builder.build()
+
+    val desc: java.util.function.Function[CmdLine, CmdDesc] = (cmdLine) => new CmdDesc(util.Arrays.asList(new AttributedString("demo")), Collections.emptyList(), Collections.emptyMap())
+    new TailTipWidgets(reader, desc, 1, TipType.COMPLETER)
+    val keyMap = reader.getKeyMaps.get("main")
+
+    object ScalaShowType {
+      val Name = "scala-show-type"
+      private var lastInvokeLocation: Option[(String, Int)] = None
+      def apply(): Boolean = {
+        val nextInvokeLocation = Some((reader.getBuffer.toString, reader.getBuffer.cursor()))
+        val cursor = reader.getBuffer.cursor()
+        val text   = reader.getBuffer.toString
+        val result = completer.complete(text, cursor, filter = true)
+        if (lastInvokeLocation == nextInvokeLocation) {
+          showTree(result)
+          lastInvokeLocation = None
+        } else {
+          showType(result)
+          lastInvokeLocation = nextInvokeLocation
+        }
+        true
+      }
+      def showType(result: shell.CompletionResult): Unit = {
+        reader.getTerminal.writer.println()
+        reader.getTerminal.writer.println(result.typeAtCursor)
+        reader.callWidget(LineReader.REDRAW_LINE)
+        reader.callWidget(LineReader.REDISPLAY)
+        reader.getTerminal.flush()
+      }
+      def showTree(result: shell.CompletionResult): Unit = {
+        reader.getTerminal.writer.println()
+        reader.getTerminal.writer.println(Naming.unmangle(result.typedTree))
+        reader.callWidget(LineReader.REDRAW_LINE)
+        reader.callWidget(LineReader.REDISPLAY)
+        reader.getTerminal.flush()
+      }
+    }
+    reader.getWidgets().put(ScalaShowType.Name, () => ScalaShowType())
+
     locally {
       import LineReader._
       // VIINS, VICMD, EMACS
       val keymap = if (config.viMode) VIINS else EMACS
       reader.getKeyMaps.put(MAIN, reader.getKeyMaps.get(keymap));
+      keyMap.bind(new Reference(ScalaShowType.Name), KeyMap.ctrl('T'))
     }
     def secure(p: java.nio.file.Path): Unit = {
       try scala.reflect.internal.util.OwnerOnlyChmod.chmodFileOrCreateEmpty(p)
@@ -177,6 +229,12 @@ object Reader {
         val (wordCursor, wordIndex) = current match {
           case Some(t) if t.isIdentifier =>
             (cursor - t.start, tokens.indexOf(t))
+          case Some(t)  =>
+            val isIdentifierStartKeyword = (t.start until t.end).forall(i => Chars.isIdentifierPart(line.charAt(i)))
+            if (isIdentifierStartKeyword)
+              (cursor - t.start, tokens.indexOf(t))
+            else
+              (0, -1)
           case _ =>
             (0, -1)
         }
@@ -233,15 +291,16 @@ object Reader {
  *  It delegates both interfaces to an underlying `Completion`.
  */
 class Completion(delegate: shell.Completion) extends shell.Completion with Completer {
+  var lastPrefix: String = ""
   require(delegate != null)
   // REPL Completion
   def complete(buffer: String, cursor: Int, filter: Boolean): shell.CompletionResult = delegate.complete(buffer, cursor, filter)
 
   // JLine Completer
   def complete(lineReader: LineReader, parsedLine: ParsedLine, newCandidates: JList[Candidate]): Unit = {
     def candidateForResult(cc: CompletionCandidate): Candidate = {
-      val value = cc.defString
-      val displayed = cc.defString + (cc.arity match {
+      val value = cc.name
+      val displayed = cc.name + (cc.arity match {
         case CompletionCandidate.Nullary => ""
         case CompletionCandidate.Nilary => "()"
         case _ => "("
@@ -257,23 +316,19 @@ 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, filter = false)
-    result.candidates.map(_.defString) 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
+    for (cc <- result.candidates)
+      newCandidates.add(candidateForResult(cc))
+
+    val parsedLineWord = parsedLine.word()
+    result.candidates.filter(_.name == parsedLineWord) match {
+      case Nil =>
+      case exacts =>
         lineReader.getTerminal.writer.println()
-        for (cc <- result.candidates.tail)
-          lineReader.getTerminal.writer.println(cc.defString)
+        for (cc <- exacts)
+          lineReader.getTerminal.writer.println(cc.declString())
         lineReader.callWidget(LineReader.REDRAW_LINE)
         lineReader.callWidget(LineReader.REDISPLAY)
         lineReader.getTerminal.flush()
-      // normal completion
-      case _ =>
-        for (cc <- result.candidates)
-          newCandidates.add(candidateForResult(cc))
     }
   }
 }

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

@@ -21,14 +21,14 @@ object NoCompletion extends Completion {
   def complete(buffer: String, cursor: Int, filter: Boolean) = NoCompletions
 }
 
-case class CompletionResult(cursor: Int, candidates: List[CompletionCandidate]) {
+case class CompletionResult(cursor: Int, candidates: List[CompletionCandidate], typeAtCursor: String = "", typedTree: String = "") {
   final def orElse(other: => CompletionResult): CompletionResult =
     if (candidates.nonEmpty) this else other
 }
 object CompletionResult {
   val empty: CompletionResult = NoCompletions
 }
-object NoCompletions extends CompletionResult(-1, Nil)
+object NoCompletions extends CompletionResult(-1, Nil, "", "")
 
 case class MultiCompletion(underlying: Completion*) extends Completion {
   override def complete(buffer: String, cursor: Int, filter: Boolean) =

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

@@ -253,7 +253,7 @@ class ILoop(config: ShellConfig, inOverride: BufferedReader = null,
           val maybes = intp.visibleSettings.filter(x => if (filter) x.name.startsWith(s) else true).map(_.name)
                                .filterNot(cond(_) { case "-"|"-X"|"-Y" => true }).sorted
           if (maybes.isEmpty) NoCompletions
-          else CompletionResult(cursor - s.length, maybes.map(CompletionCandidate(_)))
+          else CompletionResult(cursor - s.length, maybes.map(CompletionCandidate(_)), "", "")
         case _ => NoCompletions
       }
     }
@@ -554,13 +554,13 @@ class ILoop(config: ShellConfig, inOverride: BufferedReader = null,
     // condition here is a bit weird because of the weird hack we have where
     // the first candidate having an empty defString means it's not really
     // completion, but showing the method signature instead
-    if (candidates.headOption.exists(_.defString.nonEmpty)) {
+    if (candidates.headOption.exists(_.name.nonEmpty)) {
       val prefix =
         if (completions == NoCompletions) ""
         else what.substring(0, completions.cursor)
       // hvesalai (emacs sbt-mode maintainer) says it's important to echo only once and not per-line
       echo(
-        candidates.map(c => s"[completions] $prefix${c.defString}")
+        candidates.map(c => s"[completions] $prefix${c.name}")
           .mkString("\n")
       )
     }

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

@@ -138,12 +138,12 @@ trait LoopCommands {
             val completion = ":" + cmd.name
             new Completion {
               def complete(buffer: String, cursor: Int, filter: Boolean) =
-                CompletionResult(cursor, List(CompletionCandidate(completion)))
+                CompletionResult(cursor, List(CompletionCandidate(completion)), "", "")
             }
           case cmd :: rest =>
             new Completion {
               def complete(buffer: String, cursor: Int, filter: Boolean) =
-                CompletionResult(cursor, cmds.map(cmd => CompletionCandidate(":" + cmd.name)))
+                CompletionResult(cursor, cmds.map(cmd => CompletionCandidate(":" + cmd.name)), "", "")
             }
         }
       case _ => NoCompletion

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

@@ -51,16 +51,16 @@ class ReplCompletion(intp: Repl, val accumulator: Accumulator = new Accumulator)
         case Right(result) => try {
           buf match {
             case slashPrint() if cursor == buf.length =>
-              CompletionResult(cursor, CompletionCandidate.fromStrings("" :: Naming.unmangle(result.print) :: Nil))
+              CompletionResult(cursor, CompletionCandidate.fromStrings("" :: Naming.unmangle(result.print) :: Nil), "", "")
             case slashPrintRaw() if cursor == buf.length =>
-              CompletionResult(cursor, CompletionCandidate.fromStrings("" :: result.print :: Nil))
+              CompletionResult(cursor, CompletionCandidate.fromStrings("" :: result.print :: Nil), "", "")
             case slashTypeAt(start, end) if cursor == buf.length =>
-              CompletionResult(cursor, CompletionCandidate.fromStrings("" :: result.typeAt(start.toInt, end.toInt) :: Nil))
+              CompletionResult(cursor, CompletionCandidate.fromStrings("" :: result.typeAt(start.toInt, end.toInt) :: Nil), "", "")
             case _ =>
               // under JLine 3, we no longer use the tabCount concept, so tabCount is always 1
               // which always gives us all completions
               val (c, r) = result.completionCandidates(filter, tabCount = 1)
-              CompletionResult(c, r)
+              CompletionResult(c, r, result.typeAt(cursor, cursor), result.print)
           }
         } finally result.cleanup()
       }

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

@@ -784,9 +784,12 @@ class IMain(val settings: Settings, parentClassLoaderOverride: Option[ClassLoade
     // The source file contents only has the code originally input by the user,
     // with unit's body holding the synthetic trees.
     // When emitting errors, be careful not to refer to the synthetic code
-    private val unit = new CompilationUnit(new BatchSourceFile(if (synthetic) "<synthetic>" else label, line))
+    // pad with a trailing " " so that the synthetic position for enclosing trees does not exactly coincide with the
+    // position of the user-written code, these seems to confuse the presentation compiler.
+    private val paddedLine = line + " "
+    private val unit = new CompilationUnit(new BatchSourceFile(if (synthetic) "<synthetic>" else label, paddedLine))
     // a dummy position used for synthetic trees (needed for pres compiler to locate the trees for user input)
-    private val wholeUnit = Position.range(unit.source, 0, 0, line.length)
+    private val wholeUnit = Position.range(unit.source, 0, 0, paddedLine.length)
 
     private def storeInVal(tree: Tree): Tree = {
       val resName = newTermName(if (synthetic) freshInternalVarName() else freshUserVarName())
@@ -882,13 +885,13 @@ class IMain(val settings: Settings, parentClassLoaderOverride: Option[ClassLoade
         else ModuleDef(NoMods, readName, wrapperTempl))
 
       if (isClassBased)
-        stats += q"""object $readName { val INSTANCE = new ${tq"""${readName.toTypeName}"""} }"""
+        stats += atPos(wholeUnit.focus)(q"""object $readName { val INSTANCE = new ${tq"""${readName.toTypeName}"""} }""")
 
       val unspliced = PackageDef(atPos(wholeUnit.focus)(Ident(lineRep.packageName)), stats.toList)
       unit.body = spliceUserCode.transform(unspliced)
       unit.encounteredXml(firstXmlPos)
 
-//      settings.Xprintpos.value = true
+      // settings.Xprintpos.value = true
       showCode(asCompactString(unit.body))
 
       unit

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

@@ -323,18 +323,19 @@ trait PresentationCompilationResult {
   def candidates(tabCount: Int): (Int, List[String]) =
     completionCandidates(tabCount) match {
       case (cursor, cands) =>
-        (cursor, cands.map(_.defString))
+        (cursor, cands.map(_.name))
     }
 
   final def completionCandidates(tabCount: Int = -1): (Int, List[CompletionCandidate]) = completionCandidates(filter = true, tabCount)
   def completionCandidates(filter: Boolean, tabCount: Int): (Int, List[CompletionCandidate])
 }
 
 case class CompletionCandidate(
-  defString: String,
+  name: String,
   arity: CompletionCandidate.Arity = CompletionCandidate.Nullary,
   isDeprecated: Boolean = false,
-  isUniversal: Boolean = false)
+  isUniversal: Boolean = false,
+  declString: () => String = () => "")
 object CompletionCandidate {
   sealed trait Arity
   case object Nullary extends Arity