src/jdk.scripting.nashorn.shell/share/classes/jdk/nashorn/tools/jjs/Console.java

*** 23,65 ****
   * questions.
   */
  
  package jdk.nashorn.tools.jjs;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import jdk.internal.jline.NoInterruptUnixTerminal;
  import jdk.internal.jline.Terminal;
  import jdk.internal.jline.TerminalFactory;
  import jdk.internal.jline.TerminalFactory.Flavor;
  import jdk.internal.jline.WindowsTerminal;
  import jdk.internal.jline.console.ConsoleReader;
  import jdk.internal.jline.console.completer.Completer;
  import jdk.internal.jline.console.history.FileHistory;
  
  class Console implements AutoCloseable {
      private final ConsoleReader in;
      private final FileHistory history;
  
      Console(final InputStream cmdin, final PrintStream cmdout, final File historyFile,
!             final Completer completer) throws IOException {
          TerminalFactory.registerFlavor(Flavor.WINDOWS, isCygwin()? JJSUnixTerminal::new : JJSWindowsTerminal::new);
          TerminalFactory.registerFlavor(Flavor.UNIX, JJSUnixTerminal::new);
          in = new ConsoleReader(cmdin, cmdout);
          in.setExpandEvents(false);
          in.setHandleUserInterrupt(true);
          in.setBellEnabled(true);
          in.setHistory(history = new FileHistory(historyFile));
          in.addCompleter(completer);
          Runtime.getRuntime().addShutdownHook(new Thread((Runnable)this::saveHistory));
      }
  
      String readLine(final String prompt) throws IOException {
          return in.readLine(prompt);
      }
--- 23,70 ----
   * questions.
   */
  
  package jdk.nashorn.tools.jjs;
  
+ import java.awt.event.ActionListener;
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
+ import java.util.function.Function;
  import jdk.internal.jline.NoInterruptUnixTerminal;
  import jdk.internal.jline.Terminal;
  import jdk.internal.jline.TerminalFactory;
  import jdk.internal.jline.TerminalFactory.Flavor;
  import jdk.internal.jline.WindowsTerminal;
  import jdk.internal.jline.console.ConsoleReader;
+ import jdk.internal.jline.console.KeyMap;
  import jdk.internal.jline.console.completer.Completer;
  import jdk.internal.jline.console.history.FileHistory;
  
  class Console implements AutoCloseable {
+     private static final String DOCUMENTATION_SHORTCUT = "\033\133\132"; //Shift-TAB
      private final ConsoleReader in;
      private final FileHistory history;
  
      Console(final InputStream cmdin, final PrintStream cmdout, final File historyFile,
!             final Completer completer, final Function<String, String> docHelper) throws IOException {
          TerminalFactory.registerFlavor(Flavor.WINDOWS, isCygwin()? JJSUnixTerminal::new : JJSWindowsTerminal::new);
          TerminalFactory.registerFlavor(Flavor.UNIX, JJSUnixTerminal::new);
          in = new ConsoleReader(cmdin, cmdout);
          in.setExpandEvents(false);
          in.setHandleUserInterrupt(true);
          in.setBellEnabled(true);
          in.setHistory(history = new FileHistory(historyFile));
          in.addCompleter(completer);
          Runtime.getRuntime().addShutdownHook(new Thread((Runnable)this::saveHistory));
+         bind(DOCUMENTATION_SHORTCUT, (ActionListener)evt -> showDocumentation(docHelper));
      }
  
      String readLine(final String prompt) throws IOException {
          return in.readLine(prompt);
      }
*** 136,141 ****
--- 141,176 ----
      }
  
      private static boolean isCygwin() {
          return System.getenv("SHELL") != null;
      }
+ 
+     private void bind(String shortcut, Object action) {
+         KeyMap km = in.getKeys();
+         for (int i = 0; i < shortcut.length(); i++) {
+             final Object value = km.getBound(Character.toString(shortcut.charAt(i)));
+             if (value instanceof KeyMap) {
+                 km = (KeyMap) value;
+             } else {
+                 km.bind(shortcut.substring(i), action);
+             }
+         }
+     }
+ 
+     private void showDocumentation(final Function<String, String> docHelper) {
+         final String buffer = in.getCursorBuffer().buffer.toString();
+         final int cursor = in.getCursorBuffer().cursor;
+         final String doc = docHelper.apply(buffer.substring(0, cursor));
+         try {
+             if (doc != null) {
+                 in.println();
+                 in.println(doc);
+                 in.redrawLine();
+                 in.flush();
+             } else {
+                 in.beep();
+             }
+         } catch (IOException ex) {
+             throw new IllegalStateException(ex);
+         }
+     }
  }