Added a :keybindings command to the repl which ...

Added a :keybindings command to the repl which shows what each ctrl- key
does. Thanks to mark harrah for the patch even though I wrote it afresh.
Would be interested to know if it outputs anything remotely sensible on
platforms which aren't OSX. Closes #3245, no review.

5 files changed, 64 insertions, 10 deletions

diff --git a/src/compiler/scala/tools/nsc/interpreter/ILoop.scala b/src/compiler/scala/tools/nsc/interpreter/ILoop.scala
index 8e1f883b91..03ce7b182b 100644
--- a/src/compiler/scala/tools/nsc/interpreter/ILoop.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/ILoop.scala
@@ -193,6 +193,7 @@ class ILoop(in0: Option[BufferedReader], protected val out: PrintWriter)
        NoArgs("help", "print this help message", printHelp),
        VarArgs("history", "show the history (optional arg: lines to show)", printHistory),
        LineArg("h?", "search the history", searchHistory),
+       LineArg("keybindings", "show how ctrl-[A-Z] and other keys are bound", keybindingsCommand),
        OneArg("load", "load and interpret a Scala file", load),
        NoArgs("power", "enable power user mode", powerCmd),
        NoArgs("quit", "exit the interpreter", () => Result(false, None)),
@@ -211,16 +212,19 @@ class ILoop(in0: Option[BufferedReader], protected val out: PrintWriter)
       LineArg("wrap", "code to wrap around all executions", wrapCommand)
     )
   }
-  private def wrapCommand(line: String): Result = {
-    if (line == "") {
-      intp.setExecutionWrapper("")
-      "Cleared wrapper."
-    }
+  private def keybindingsCommand(line: String): Result = {
+    if (in.keyBindings.isEmpty) "Key bindings unavailable."
     else {
-      intp.setExecutionWrapper(line)
-      "Set wrapper to '" + line + "'"
+      println("Reading jline properties for default key bindings.")
+      println("Accuracy not guaranteed: treat this as a guideline only.\n")
+      in.keyBindings foreach println
     }
   }
+  private def wrapCommand(line: String): Result = {
+    intp setExecutionWrapper line
+    if (line == "") "Cleared wrapper."
+    else "Set wrapper to '" + line + "'"
+  }
 
   private def symfilterCmd(line: String): Result = {
     if (line == "") {
@@ -404,7 +408,11 @@ class ILoop(in0: Option[BufferedReader], protected val out: PrintWriter)
     commands.filter(_.name startsWith cmd) match {
       case List(x)  => x(args)
       case Nil      => withError("Unknown command.  Type :help for help.")
-      case xs       => withError(ambiguous(xs))
+      case xs       =>
+        xs find (_.name == cmd) match {
+          case Some(exact)  => exact(args)
+          case _            => withError(ambiguous(xs))
+        }
     }
   }
 
diff --git a/src/compiler/scala/tools/nsc/interpreter/InteractiveReader.scala b/src/compiler/scala/tools/nsc/interpreter/InteractiveReader.scala
index 1a67cc647d..1ee04a4090 100644
--- a/src/compiler/scala/tools/nsc/interpreter/InteractiveReader.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/InteractiveReader.scala
@@ -18,6 +18,7 @@ trait InteractiveReader {
 
   def history: History
   def completion: Completion
+  def keyBindings: List[KeyBinding]
 
   def init(): Unit
   def reset(): Unit
diff --git a/src/compiler/scala/tools/nsc/interpreter/JLineReader.scala b/src/compiler/scala/tools/nsc/interpreter/JLineReader.scala
index 7652e6646b..f0868046b1 100644
--- a/src/compiler/scala/tools/nsc/interpreter/JLineReader.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/JLineReader.scala
@@ -17,14 +17,19 @@ import scala.tools.jline.console.ConsoleReader
 import scala.collection.JavaConverters._
 import Properties.userHome
 import Completion._
+import io.Streamable.slurp
 
 /** Reads from the console using JLine */
 class JLineReader(val completion: Completion) extends InteractiveReader {
   val interactive = true
   lazy val history = JLineHistory()
+  lazy val keyBindings =
+    try KeyBinding parse slurp(term.getDefaultBindings)
+    catch { case _: Exception => Nil }
 
-  def reset() = consoleReader.getTerminal().reset()
-  def init()  = consoleReader.getTerminal().init()
+  private def term = consoleReader.getTerminal()
+  def reset() = term.reset()
+  def init()  = term.init()
 
   def scalaToJline(tc: ScalaCompleter): Completer = new Completer {
     def complete(_buf: String, cursor: Int, candidates: JList[CharSequence]): Int = {
diff --git a/src/compiler/scala/tools/nsc/interpreter/KeyBinding.scala b/src/compiler/scala/tools/nsc/interpreter/KeyBinding.scala
new file mode 100644
index 0000000000..a7ca3a77f3
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/interpreter/KeyBinding.scala
@@ -0,0 +1,39 @@
+/* NSC -- new Scala compiler
+ * Copyright 2005-2011 LAMP/EPFL
+ * @author Paul Phillips
+ */
+
+package scala.tools.nsc
+package interpreter
+
+case class KeyBinding(name: String, code: Int, aliases: List[String], description: String) {
+  def nameString = if (aliases.nonEmpty) aliases mkString ", " else name
+  override def toString = "%3d %s: %s".format(code, nameString, description)
+}
+
+object KeyBinding {
+  def parse(bindings: String): List[KeyBinding] = {
+    def loop(xs: List[String]): List[KeyBinding] = {
+      val (comment, lines) = xs span (_ startsWith "#")
+      val description = comment map (_ drop 1 trim) mkString " "
+      val (aliases, desc) = description span (_ != ':') match {
+        case (x, y) => (
+          x split ',' map (_.trim) toList,
+          if (y == "") "" else y.tail.trim
+        )
+      }
+      lines match {
+        case Nil      => Nil
+        case hd :: tl =>
+          val kb = (hd indexOf '=') match {
+            case -1   => KeyBinding(hd, -1, aliases, desc)
+            case idx  => KeyBinding(hd drop idx + 1, hd take idx toInt, aliases, desc)
+          }
+          kb :: loop(tl)
+      }
+    }
+    // This is verrrrrrrry specific to the current contents
+    // of the keybindings.properties in jline.
+    loop(bindings split "\\n" map (_.trim) dropWhile (_ != "") filterNot (_ == "") toList) sortBy (_.code)
+  }
+}
diff --git a/src/compiler/scala/tools/nsc/interpreter/SimpleReader.scala b/src/compiler/scala/tools/nsc/interpreter/SimpleReader.scala
index 079fa4b9fb..0e3b7412c8 100644
--- a/src/compiler/scala/tools/nsc/interpreter/SimpleReader.scala
+++ b/src/compiler/scala/tools/nsc/interpreter/SimpleReader.scala
@@ -17,6 +17,7 @@ extends InteractiveReader
 {
   val history = NoHistory
   val completion = NoCompletion
+  val keyBindings: List[KeyBinding] = Nil
 
   def init() = ()
   def reset() = ()