Migrate to jline3

src/org/rascalmpl/ideservices/BasicIDEServices.java

@@ -34,16 +34,26 @@
 public class BasicIDEServices implements IDEServices {
   private final IRascalMonitor monitor;
   private final PrintWriter stderr;
+  private final Runnable clearRepl;
 
   public BasicIDEServices(PrintWriter stderr, IRascalMonitor monitor){
+    this(stderr, monitor, () -> {});
+  }
+  public BasicIDEServices(PrintWriter stderr, IRascalMonitor monitor, Runnable clearRepl){
     this.stderr = stderr;
     this.monitor = monitor;
+    this.clearRepl = clearRepl;
   }
 
   @Override
   public PrintWriter stderr() {
     return stderr;
   }
+
+  @Override
+  public void clearRepl() {
+    this.clearRepl.run();
+  }
 
   public void browse(ISourceLocation loc, String title, int viewColumn){
       browse(loc.getURI(), title, viewColumn);

src/org/rascalmpl/ideservices/IDEServices.java

@@ -73,6 +73,10 @@ default void unregisterLanguage(IConstructor language) {
     throw new UnsupportedOperationException("registerLanguage is not implemented in this environment.");
   }
 
+  default void clearRepl() {
+    throw new UnsupportedOperationException("Clear REPL is not supported in this IDE Service");
+  }
+
   /**
    * Asks the IDE to apply document edits as defined in the standard library module
    * analysis::diff::edits::TextEdits, according to the semantics defined in

src/org/rascalmpl/repl/BaseREPL2.java

@@ -19,6 +19,7 @@
 import org.jline.terminal.Terminal.Signal;
 import org.jline.terminal.Terminal.SignalHandler;
 import org.jline.utils.ShutdownHooks;
+import org.jline.utils.InfoCmp.Capability;
 
 public class BaseREPL2 {
 
@@ -89,6 +90,7 @@ public BaseREPL2(IREPLService replService, Terminal term) {
         // - support for html results 
         // - measure time
         // - history?
+        // - possible to tee output
     }
 
     public void run() throws IOException {

src/org/rascalmpl/repl/completers/RascalCommandCompletion.java

@@ -35,7 +35,7 @@ public class RascalCommandCompletion implements Completer {
         COMMAND_KEYWORDS.put("history", "history"); // TODO: figure out what it does
         COMMAND_KEYWORDS.put("test", "run rest modules");
         COMMAND_KEYWORDS.put("modules", "show imported modules");// TODO: figure out what it does 
-        COMMAND_KEYWORDS.put("clear", "clear evaluator");// TODO: figure out what it does 
+        COMMAND_KEYWORDS.put("clear", "clear repl screen");
     }
 
     private final NavigableMap<String, String> setOptions;

src/org/rascalmpl/semantics/dynamic/ShellCommand.java

@@ -66,7 +66,16 @@ public Clear(ISourceLocation __param1, IConstructor tree) {
 
 		@Override
 		public Result<IValue> interpret(IEvaluator<Result<IValue>> __eval) {
-			return null;
+			IRascalMonitor monitor = __eval.getMonitor();
+
+			if (monitor instanceof IDEServices) {
+				IDEServices services = (IDEServices) monitor;
+				services.clearRepl();
+			}
+			else {
+				__eval.getStdErr().println("The current Rascal execution environment does not know how to clear the REPL.");
+			}
+			return org.rascalmpl.interpreter.result.ResultFactory.nothing();
 		}
 
 	}

src/org/rascalmpl/shell/RascalShell2.java

@@ -19,6 +19,7 @@
 
 import org.jline.terminal.TerminalBuilder;
 import org.jline.utils.OSUtils;
+import org.jline.utils.InfoCmp.Capability;
 import org.rascalmpl.ideservices.BasicIDEServices;
 import org.rascalmpl.ideservices.IDEServices;
 import org.rascalmpl.interpreter.Evaluator;
@@ -55,13 +56,13 @@ public static void main(String[] args) throws IOException {
 
             var repl = new BaseREPL2(new RascalReplServices((t) -> {
                 var monitor = new TerminalProgressBarMonitor(term);
-                IDEServices services = new BasicIDEServices(term.writer(), monitor);
+                IDEServices services = new BasicIDEServices(term.writer(), monitor, () -> term.puts(Capability.clear_screen));
 
 
                 GlobalEnvironment heap = new GlobalEnvironment();
                 ModuleEnvironment root = heap.addModule(new ModuleEnvironment(ModuleEnvironment.SHELL_MODULE, heap));
                 IValueFactory vf = ValueFactoryFactory.getValueFactory();
-                Evaluator evaluator = new Evaluator(vf, term.reader(), new PrintWriter(System.err, true), term.writer(), root, heap, monitor);
+                Evaluator evaluator = new Evaluator(vf, term.reader(), new PrintWriter(System.err, true), term.writer(), root, heap, services);
                 evaluator.addRascalSearchPathContributor(StandardLibraryContributor.getInstance());
                 return evaluator;
             }), term);