--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.sl.tools/src/com/oracle/truffle/sl/tools/debug/SLREPLServer.java	Tue May 26 16:38:13 2015 -0700
@@ -0,0 +1,233 @@
+/*
+ * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.sl.tools.debug;
+
+import java.io.*;
+import java.util.*;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.instrument.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.source.*;
+import com.oracle.truffle.tools.debug.engine.*;
+import com.oracle.truffle.tools.debug.shell.*;
+import com.oracle.truffle.tools.debug.shell.client.*;
+import com.oracle.truffle.tools.debug.shell.server.*;
+import com.oracle.truffle.sl.factory.*;
+import com.oracle.truffle.sl.runtime.*;
+
+/**
+ * Instantiation of the "server" side of the "REPL*" debugger for the Simple language.
+ * <p>
+ * The SL parser is not equipped to parse program fragments, so any debugging functions that depend
+ * on this are not supported, for example {@link DebugEngine#eval(Source, Node, MaterializedFrame)}
+ * and {@link Breakpoint#setCondition(String)}.
+ *
+ * @see SimpleREPLClient
+ */
+public final class SLREPLServer implements REPLServer {
+    public static void main(String[] args) {
+        // Cheating for the prototype: start from SL, rather than from the client.
+        final SLREPLServer server = new SLREPLServer();
+        final SimpleREPLClient client = new SimpleREPLClient(server.slContext, server);
+
+        // Cheating for the prototype: allow server access to client for recursive debugging
+        server.setClient(client);
+
+        try {
+            client.start();
+        } catch (QuitException ex) {
+        }
+    }
+
+    private final SLContext slContext;
+    private final DebugEngine slDebugEngine;
+    private final String statusPrefix;
+    private final Map<String, REPLHandler> handlerMap = new HashMap<>();
+    private SLServerContext currentServerContext;
+    private SimpleREPLClient replClient = null;
+
+    private void add(REPLHandler fileHandler) {
+        handlerMap.put(fileHandler.getOp(), fileHandler);
+    }
+
+    public SLREPLServer() {
+        add(REPLHandler.BACKTRACE_HANDLER);
+        add(REPLHandler.BREAK_AT_LINE_HANDLER);
+        add(REPLHandler.BREAK_AT_LINE_ONCE_HANDLER);
+        add(REPLHandler.BREAK_AT_THROW_HANDLER);
+        add(REPLHandler.BREAK_AT_THROW_ONCE_HANDLER);
+        add(REPLHandler.BREAKPOINT_INFO_HANDLER);
+        add(REPLHandler.CLEAR_BREAK_HANDLER);
+        add(REPLHandler.CONTINUE_HANDLER);
+        add(REPLHandler.DELETE_HANDLER);
+        add(REPLHandler.DISABLE_BREAK_HANDLER);
+        add(REPLHandler.ENABLE_BREAK_HANDLER);
+        add(REPLHandler.FILE_HANDLER);
+        add(REPLHandler.FRAME_HANDLER);
+        add(SLREPLHandler.INFO_HANDLER);
+        add(REPLHandler.KILL_HANDLER);
+        add(SLREPLHandler.LOAD_RUN_SOURCE_HANDLER);
+        add(SLREPLHandler.LOAD_STEP_SOURCE_HANDLER);
+        add(REPLHandler.QUIT_HANDLER);
+        add(REPLHandler.STEP_INTO_HANDLER);
+        add(REPLHandler.STEP_OUT_HANDLER);
+        add(REPLHandler.STEP_OVER_HANDLER);
+        add(REPLHandler.TRUFFLE_HANDLER);
+        add(REPLHandler.TRUFFLE_NODE_HANDLER);
+
+        // Set up an SL context
+        this.slContext = SLContextFactory.create(null, new PrintWriter(System.out));
+
+        final SLSourceExecutionProvider slSourceExecution = new SLSourceExecutionProvider(slContext);
+        final SLREPLDebugClient slDebugClient = new SLREPLDebugClient(this.slContext);
+        this.slDebugEngine = DebugEngine.create(slDebugClient, slSourceExecution);
+        this.statusPrefix = slContext.getLanguageShortName() + " REPL:";
+    }
+
+    private void setClient(SimpleREPLClient replClient) {
+        this.replClient = replClient;
+    }
+
+    public REPLMessage start() {
+
+        this.currentServerContext = new SLServerContext(null, null, null);
+
+        // SL doesn't load modules (like other languages), so we just return a success
+        final REPLMessage reply = new REPLMessage();
+        reply.put(REPLMessage.STATUS, REPLMessage.SUCCEEDED);
+        reply.put(REPLMessage.DISPLAY_MSG, slContext.getLanguageShortName() + " started");
+        return reply;
+    }
+
+    public REPLMessage[] receive(REPLMessage request) {
+        if (currentServerContext == null) {
+            final REPLMessage message = new REPLMessage();
+            message.put(REPLMessage.STATUS, REPLMessage.FAILED);
+            message.put(REPLMessage.DISPLAY_MSG, "server not started");
+            final REPLMessage[] reply = new REPLMessage[]{message};
+            return reply;
+        }
+        return currentServerContext.receive(request);
+    }
+
+    /**
+     * Execution context of a halted SL program.
+     */
+    public final class SLServerContext extends REPLServerContext {
+
+        private final SLServerContext predecessor;
+
+        public SLServerContext(SLServerContext predecessor, Node astNode, MaterializedFrame mFrame) {
+            super(predecessor == null ? 0 : predecessor.getLevel() + 1, astNode, mFrame);
+            this.predecessor = predecessor;
+        }
+
+        @Override
+        public REPLMessage[] receive(REPLMessage request) {
+            final String command = request.get(REPLMessage.OP);
+            final REPLHandler handler = handlerMap.get(command);
+
+            if (handler == null) {
+                final REPLMessage message = new REPLMessage();
+                message.put(REPLMessage.OP, command);
+                message.put(REPLMessage.STATUS, REPLMessage.FAILED);
+                message.put(REPLMessage.DISPLAY_MSG, statusPrefix + " op \"" + command + "\" not supported");
+                final REPLMessage[] reply = new REPLMessage[]{message};
+                return reply;
+            }
+            return handler.receive(request, currentServerContext);
+        }
+
+        @Override
+        public SLContext getLanguageContext() {
+            return slContext;
+        }
+
+        @Override
+        public DebugEngine getDebugEngine() {
+            return slDebugEngine;
+        }
+
+    }
+
+    /**
+     * Specialize the standard SL debug context by notifying the REPL client when execution is
+     * halted, e.g. at a breakpoint.
+     * <p>
+     * Before notification, the server creates a new context at the halted location, in which
+     * subsequent evaluations take place until such time as the client says to "continue".
+     * <p>
+     * This implementation "cheats" the intended asynchronous architecture by calling back directly
+     * to the client with the notification.
+     */
+    private final class SLREPLDebugClient implements DebugClient {
+
+        private final SLContext slContext;
+
+        SLREPLDebugClient(SLContext slContext) {
+            this.slContext = slContext;
+        }
+
+        public void haltedAt(Node node, MaterializedFrame mFrame, List<String> warnings) {
+            // Create and push a new debug context where execution is halted
+            currentServerContext = new SLServerContext(currentServerContext, node, mFrame);
+
+            // Message the client that execution is halted and is in a new debugging context
+            final REPLMessage message = new REPLMessage();
+            message.put(REPLMessage.OP, REPLMessage.STOPPED);
+            final SourceSection src = node.getSourceSection();
+            final Source source = src.getSource();
+            message.put(REPLMessage.SOURCE_NAME, source.getName());
+            message.put(REPLMessage.FILE_PATH, source.getPath());
+            message.put(REPLMessage.LINE_NUMBER, Integer.toString(src.getStartLine()));
+            message.put(REPLMessage.STATUS, REPLMessage.SUCCEEDED);
+            message.put(REPLMessage.DEBUG_LEVEL, Integer.toString(currentServerContext.getLevel()));
+            if (!warnings.isEmpty()) {
+                final StringBuilder sb = new StringBuilder();
+                for (String warning : warnings) {
+                    sb.append(warning + "\n");
+                }
+                message.put(REPLMessage.WARNINGS, sb.toString());
+            }
+            try {
+                // Cheat with synchrony: call client directly about entering a nested debugging
+                // context.
+                replClient.halted(message);
+            } finally {
+                // Returns when "continue" is called in the new debugging context
+
+                // Pop the debug context, and return so that the old context will continue
+                currentServerContext = currentServerContext.predecessor;
+            }
+        }
+
+        public ExecutionContext getExecutionContext() {
+            return slContext;
+        }
+    }
+
+}