Misc debugger enhancements and bug fixes....

src/d8.js

Index: src/d8.js
===================================================================
--- src/d8.js	(revision 6165)
+++ src/d8.js	(working copy)
@@ -110,17 +110,32 @@
 const kNoFrame = -1;
 Debug.State = {
   currentFrame: kNoFrame,
+  displaySourceStartLine: -1,
+  displaySourceEndLine: -1,
   currentSourceLine: -1
 }
 var trace_compile = false;  // Tracing all compile events?
+var trace_debug_json = false; // Tracing all debug json packets?
+var last_cmd_line = '';
+var repeat_cmd_line = '';
+var is_running = true;
 
+// Copied from debug-delay.js.  This is needed below:
+function ScriptTypeFlag(type) {
+  return (1 << type);
+}
 
+
 // Process a debugger JSON message into a display text and a running status.
 // This function returns an object with properties "text" and "running" holding
 // this information.
 function DebugMessageDetails(message) {
+  if (trace_debug_json) {
+    print("received: '" + message + "'");
+  }
   // Convert the JSON string to an object.
   var response = new ProtocolPackage(message);
+  is_running = response.running();
 
   if (response.type() == 'event') {
     return DebugEventDetails(response);
@@ -161,6 +176,8 @@
       result += '\n';
       result += SourceUnderline(body.sourceLineText, body.sourceColumn);
       Debug.State.currentSourceLine = body.sourceLine;
+      Debug.State.displaySourceStartLine = -1;
+      Debug.State.displaySourceEndLine = -1;
       Debug.State.currentFrame = 0;
       details.text = result;
       break;
@@ -180,10 +197,14 @@
         result += '\n';
         result += SourceUnderline(body.sourceLineText, body.sourceColumn);
         Debug.State.currentSourceLine = body.sourceLine;
+        Debug.State.displaySourceStartLine = -1;
+        Debug.State.displaySourceEndLine = -1;
         Debug.State.currentFrame = 0;
       } else {
         result += ' (empty stack)';
         Debug.State.currentSourceLine = -1;
+        Debug.State.displaySourceStartLine = -1;
+        Debug.State.displaySourceEndLine = -1;
         Debug.State.currentFrame = kNoFrame;
       }
       details.text = result;
@@ -202,6 +223,10 @@
       details.text = result;
       break;
 
+    case 'scriptCollected':
+      details.text = result;
+      break;
+
     default:
       details.text = 'Unknown debug event ' + response.event();
   }
@@ -254,7 +279,11 @@
 
 // Converts a text command to a JSON request.
 function DebugCommandToJSONRequest(cmd_line) {
-  return new DebugRequest(cmd_line).JSONRequest();
+  var result = new DebugRequest(cmd_line).JSONRequest();
+  if (trace_debug_json && result) {
+    print("sending: '" + result + "'");
+  }
+  return result;
 };
 
 
@@ -266,6 +295,20 @@
     return;
   }
 
+  // Check for a simple carriage return to repeat the last command:
+  var is_repeating = false;
+  if (cmd_line == '\n') {
+    if (is_running) {
+      cmd_line = 'break'; // Not in debugger mode, break with a frame request.
+    } else {
+      cmd_line = repeat_cmd_line; // use command to repeat.
+      is_repeating = true;
+    }
+  }
+  if (!is_running) { // Only save the command if in debugger mode.
+    repeat_cmd_line = cmd_line;   // save last command.
+  }
+
   // Trim string for leading and trailing whitespace.
   cmd_line = cmd_line.replace(/^\s+|\s+$/g, '');
 
@@ -281,6 +324,13 @@
     args = cmd_line.slice(pos).replace(/^\s+|\s+$/g, '');
   }
 
+  if ((cmd === undefined) || !cmd) {
+    this.request_ = void 0;
+    return;
+  }
+
+  last_cmd = cmd;
+
   // Switch on command.
   switch (cmd) {
     case 'continue':
@@ -290,9 +340,24 @@
 
     case 'step':
     case 's':
-      this.request_ = this.stepCommandToJSONRequest_(args);
+      this.request_ = this.stepCommandToJSONRequest_(args, 'in');
       break;
 
+    case 'stepi':
+    case 'si':
+      this.request_ = this.stepCommandToJSONRequest_(args, 'min');
+      break;
+
+    case 'next':
+    case 'n':
+      this.request_ = this.stepCommandToJSONRequest_(args, 'next');
+      break;
+
+    case 'finish':
+    case 'fin':
+      this.request_ = this.stepCommandToJSONRequest_(args, 'out');
+      break;
+
     case 'backtrace':
     case 'bt':
       this.request_ = this.backtraceCommandToJSONRequest_(args);
@@ -311,6 +376,26 @@
       this.request_ = this.scopeCommandToJSONRequest_(args);
       break;
 
+    case 'disconnect':
+    case 'exit':
+    case 'quit':
+      this.request_ = this.disconnectCommandToJSONRequest_(args);
+      break;
+
+    case 'up':
+      this.request_ =
+          this.frameCommandToJSONRequest_('' +
+                                          (Debug.State.currentFrame + 1));
+      break;
+      
+    case 'down':
+    case 'do':
+      this.request_ =
+          this.frameCommandToJSONRequest_('' +
+                                          (Debug.State.currentFrame - 1));
+      break;
+      
+    case 'set':
     case 'print':
     case 'p':
       this.request_ = this.printCommandToJSONRequest_(args);
@@ -328,11 +413,17 @@
       this.request_ = this.instancesCommandToJSONRequest_(args);
       break;
 
+    case 'list':
+    case 'l':
+      this.request_ = this.listCommandToJSONRequest_(args);
+      break;
     case 'source':
       this.request_ = this.sourceCommandToJSONRequest_(args);
       break;
 
     case 'scripts':
+    case 'script':
+    case 'scr':
       this.request_ = this.scriptsCommandToJSONRequest_(args);
       break;
 
@@ -347,6 +438,8 @@
       break;
 
     case 'clear':
+    case 'delete':
+    case 'd':
       this.request_ = this.clearCommandToJSONRequest_(args);
       break;
 
@@ -354,7 +447,42 @@
       this.request_ = this.threadsCommandToJSONRequest_(args);
       break;
 
+    case 'cond':
+      this.request_ = this.changeBreakpointCommandToJSONRequest_(args, 'cond');
+      break;
+
+    case 'enable':
+    case 'en':
+      this.request_ =
+          this.changeBreakpointCommandToJSONRequest_(args, 'enable');
+      break;
+
+    case 'disable':
+    case 'dis':
+      this.request_ =
+          this.changeBreakpointCommandToJSONRequest_(args, 'disable');
+      break;
+
+    case 'ignore':
+      this.request_ =
+          this.changeBreakpointCommandToJSONRequest_(args, 'ignore');
+      break;
+
+    case 'info':
+    case 'inf':
+      this.request_ = this.infoCommandToJSONRequest_(args);
+      break;
+
+    case 'flags':
+      this.request_ = this.v8FlagsToJSONRequest_(args);
+      break;
+
+    case 'gc':
+      this.request_ = this.gcToJSONRequest_(args);
+      break;
+
     case 'trace':
+    case 'tr':
       // Return undefined to indicate command handled internally (no JSON).
       this.request_ = void 0;
       this.traceCommand_(args);
@@ -370,8 +498,6 @@
     default:
       throw new Error('Unknown command "' + cmd + '"');
   }
-
-  last_cmd = cmd;
 }
 
 DebugRequest.prototype.JSONRequest = function() {
@@ -465,59 +591,73 @@
 
 
 // Create a JSON request for the step command.
-DebugRequest.prototype.stepCommandToJSONRequest_ = function(args) {
+DebugRequest.prototype.stepCommandToJSONRequest_ = function(args, type) {
   // Requesting a step is through the continue command with additional
   // arguments.
   var request = this.createRequest('continue');
   request.arguments = {};
 
   // Process arguments if any.
+
+  // Only process args if the command is 'step' which is indicated by type being
+  // set to 'in'.  For all other commands, ignore the args.
   if (args && args.length > 0) {
-    args = args.split(/\s*[ ]+\s*/g);
+    args = args.split(/\s+/g);
 
     if (args.length > 2) {
       throw new Error('Invalid step arguments.');
     }
 
     if (args.length > 0) {
-      // Get step count argument if any.
-      if (args.length == 2) {
-        var stepcount = parseInt(args[1]);
-        if (isNaN(stepcount) || stepcount <= 0) {
-          throw new Error('Invalid step count argument "' + args[0] + '".');
+      // Check if we have a gdb stype step command.  If so, the 1st arg would
+      // be the step count.  If it's not a number, then assume that we're
+      // parsing for the legacy v8 step command.
+      var stepcount = Number(args[0]);
+      if (stepcount == Number.NaN) {
+        // No step count at arg 1.  Process as legacy d8 step command:
+        if (args.length == 2) {
+          var stepcount = parseInt(args[1]);
+          if (isNaN(stepcount) || stepcount <= 0) {
+            throw new Error('Invalid step count argument "' + args[0] + '".');
+          }
+          request.arguments.stepcount = stepcount;
         }
-        request.arguments.stepcount = stepcount;
-      }
 
-      // Get the step action.
-      switch (args[0]) {
-        case 'in':
-        case 'i':
-          request.arguments.stepaction = 'in';
-          break;
+        // Get the step action.
+        switch (args[0]) {
+          case 'in':
+          case 'i':
+            request.arguments.stepaction = 'in';
+            break;
 
-        case 'min':
-        case 'm':
-          request.arguments.stepaction = 'min';
-          break;
+          case 'min':
+          case 'm':
+            request.arguments.stepaction = 'min';
+            break;
 
-        case 'next':
-        case 'n':
-          request.arguments.stepaction = 'next';
-          break;
+          case 'next':
+          case 'n':
+            request.arguments.stepaction = 'next';
+            break;
 
-        case 'out':
-        case 'o':
-          request.arguments.stepaction = 'out';
-          break;
+          case 'out':
+          case 'o':
+            request.arguments.stepaction = 'out';
+            break;
 
-        default:
-          throw new Error('Invalid step argument "' + args[0] + '".');
+          default:
+            throw new Error('Invalid step argument "' + args[0] + '".');
+        }
+
+      } else {
+        // gdb style step commands:
+        request.arguments.stepaction = type;
+        request.arguments.stepcount = stepcount;
       }
     }
   } else {
-    // Default is step next.
-    request.arguments.stepaction = 'next';
+    // Default is step of the specified type.
+    request.arguments.stepaction = type;
   }
 
   return request.toJSONProtocol();
@@ -648,6 +788,41 @@
 };
 
 
+// Create a JSON request for the list command.
+DebugRequest.prototype.listCommandToJSONRequest_ = function(args) {
+
+  // Default is ten lines starting five lines before the current location.
+  if (Debug.State.displaySourceEndLine == -1) {
+    // If we list forwards, we will start listing after the last source end
+    // line.  Set it to start from 5 lines before the current location.
+    Debug.State.displaySourceEndLine = Debug.State.currentSourceLine - 5;
+    // If we list backwards, we will start listing backwards from the last
+    // source start line.  Set it to start from 1 lines before the current
+    // location.
+    Debug.State.displaySourceStartLine = Debug.State.currentSourceLine + 1;
+  }
+
+  var from = Debug.State.displaySourceEndLine + 1;
+  var lines = 10;
+
+  // Parse the arguments.
+  args = args.split(/\s*,\s*/g);
+  if (args == '') {
+  } else if ((args.length == 1) && (args[0] == '-')) {
+    from = Debug.State.displaySourceStartLine - lines;
+  } else if (args.length == 2) {
+    from = parseInt(args[0]);
+    lines = parseInt(args[1]) - from + 1; // inclusive of the ending line.
+  } else {
+    throw new Error('Invalid list arguments.');
+  }
+  Debug.State.displaySourceStartLine = from;
+  Debug.State.displaySourceEndLine = from + lines - 1;
+  var sourceArgs = '' + from + ' ' + lines;
+  return this.sourceCommandToJSONRequest_(sourceArgs);
+};
+
+
 // Create a JSON request for the source command.
 DebugRequest.prototype.sourceCommandToJSONRequest_ = function(args) {
   // Build a evaluate request from the text command.
@@ -709,7 +884,10 @@
         break;
 
       default:
-        throw new Error('Invalid argument "' + args[0] + '".');
+        // If the arg is not one of the know one aboves, then it must be a
+        // filter used for filtering the results:
+        request.arguments.filter = args[0];
+        break;
     }
   }
 
@@ -731,6 +909,8 @@
 
     var request = this.createRequest('setbreakpoint');
 
+    // Break the args into target spec and condition if appropriate.
+
     // Check for breakpoint condition.
     pos = args.indexOf(' ');
     if (pos > 0) {
@@ -801,6 +981,178 @@
 };
 
 
+// Create a JSON request for the change breakpoint command.
+DebugRequest.prototype.changeBreakpointCommandToJSONRequest_ =
+    function(args, command) {
+
+  var request;
+
+  // Check for exception breaks first:
+  //   en[able] exc[eptions] [all|unc[aught]]
+  //   en[able] [all|unc[aught]] exc[eptions]
+  //   dis[able] exc[eptions] [all|unc[aught]]
+  //   dis[able] [all|unc[aught]] exc[eptions]
+  if ((command == 'enable' || command == 'disable') &&
+      args && args.length > 1) {
+    var nextPos = args.indexOf(' ');
+    var arg1 = (nextPos > 0) ? args.substring(0, nextPos) : args;
+    var excType = null;
+
+    // Check for:
+    //   en[able] exc[eptions] [all|unc[aught]]
+    //   dis[able] exc[eptions] [all|unc[aught]]
+    if (arg1 == 'exc' || arg1 == 'exception' || arg1 == 'exceptions') {
+
+      var arg2 = (nextPos > 0) ?
+          args.substring(nextPos + 1, args.length) : 'all';
+      if (!arg2) {
+        arg2 = 'all'; // if unspecified, set for all.
+      } if (arg2 == 'unc') { // check for short cut.
+        arg2 = 'uncaught';
+      }
+      excType = arg2;
+      
+    // Check for:
+    //   en[able] [all|unc[aught]] exc[eptions]
+    //   dis[able] [all|unc[aught]] exc[eptions]
+    } else if (arg1 == 'all' || arg1 == 'unc' || arg1 == 'uncaught') {
+
+      var arg2 = (nextPos > 0) ?
+          args.substring(nextPos + 1, args.length) : null;
+      if (arg2 == 'exc' || arg1 == 'exception' || arg1 == 'exceptions') {
+        excType = arg1;
+        if (excType == 'unc') {
+          excType = 'uncaught';
+        }
+      }
+    }
+
+    // If we matched one of the command formats, then excType will be non-null:
+    if (excType) {
+      // Build a evaluate request from the text command.
+      request = this.createRequest('setexceptionbreak');
+
+      request.arguments = {};
+      request.arguments.type = excType;
+      request.arguments.enabled = (command == 'enable');
+
+      return request.toJSONProtocol();
+    }
+  }
+
+  // Build a evaluate request from the text command.
+  request = this.createRequest('changebreakpoint');
+
+  // Process arguments if any.
+  if (args && args.length > 0) {
+    request.arguments = {};
+    var pos = args.indexOf(' ');
+    var breakpointArg = args;
+    var otherArgs;
+    if (pos > 0) {
+      breakpointArg = args.substring(0, pos);
+      otherArgs = args.substring(pos + 1, args.length);
+    }
+
+    request.arguments.breakpoint = parseInt(breakpointArg);
+
+    switch(command) {
+      case 'cond':
+        request.arguments.condition = otherArgs ? otherArgs : null;
+        break;
+      case 'enable':
+        request.arguments.enabled = true;
+        break;
+      case 'disable':
+        request.arguments.enabled = false;
+        break;
+      case 'ignore':
+        request.arguments.ignoreCount = parseInt(otherArgs);
+        break;
+      default:
+        throw new Error('Invalid arguments.');  
+	}
+  } else {
+    throw new Error('Invalid arguments.');
+  }
+
+  return request.toJSONProtocol();
+};
+
+
+// Create a JSON request for the disconnect command.
+DebugRequest.prototype.disconnectCommandToJSONRequest_ = function(args) {
+  var request;
+  request = this.createRequest('disconnect');
+  return request.toJSONProtocol();
+};
+
+
+// Create a JSON request for the info command.
+DebugRequest.prototype.infoCommandToJSONRequest_ = function(args) {
+  var request;
+  if (args && (args == 'break' || args == 'br')) {
+    // Build a evaluate request from the text command.
+    request = this.createRequest('listbreakpoints');
+	last_cmd = 'info break';
+  } else if (args && (args == 'locals' || args == 'lo')) {
+    // Build a evaluate request from the text command.
+	request = this.createRequest('frame');
+	last_cmd = 'info locals';
+  } else if (args && (args == 'args' || args == 'ar')) {
+    // Build a evaluate request from the text command.
+	request = this.createRequest('frame');
+	last_cmd = 'info args';
+  } else {
+    throw new Error('Invalid info arguments.');
+  }
+
+  return request.toJSONProtocol();
+};
+
+
+DebugRequest.prototype.v8FlagsToJSONRequest_ = function(args) {
+  var request;
+  request = this.createRequest('v8flags');
+  request.arguments = {};
+  request.arguments.flags = args;
+  return request.toJSONProtocol();
+};
+
+
+DebugRequest.prototype.gcToJSONRequest_ = function(args) {
+  var request;
+  if (!args) {
+    args = 'all';
+  }
+  var args = args.split(/\s+/g);
+  var cmd = args[0];
+
+  switch(cmd) {
+    case 'all':
+    case 'quick':
+    case 'full':
+    case 'young':
+    case 'old':
+    case 'compact':
+    case 'sweep':
+    case 'scavenge': {
+      if (cmd == 'young') { cmd = 'quick'; }
+      else if (cmd == 'old') { cmd = 'full'; }
+
+      request = this.createRequest('gc');
+      request.arguments = {};
+      request.arguments.type = cmd;
+      break;
+    }
+      // Else fall thru to the default case below to report the error.
+    default:
+      throw new Error('Missing arguments after ' + cmd + '.');
+  }
+  return request.toJSONProtocol();
+};
+
+
 // Create a JSON request for the threads command.
 DebugRequest.prototype.threadsCommandToJSONRequest_ = function(args) {
   // Build a threads request from the text command.
@@ -816,6 +1168,10 @@
     if (args == 'compile') {
       trace_compile = !trace_compile;
       print('Tracing of compiled scripts ' + (trace_compile ? 'on' : 'off'));
+    } else if (args === 'debug json' || args === 'json' || args === 'packets') {
+      trace_debug_json = !trace_debug_json;
+      print('Tracing of debug json packets ' +
+            (trace_debug_json ? 'on' : 'off'));
     } else {
       throw new Error('Invalid trace arguments.');
     }
@@ -831,24 +1187,63 @@
     print('warning: arguments to \'help\' are ignored');
   }
 
-  print('break');
-  print('break location [condition]');
-  print('  break on named function: location is a function name');
-  print('  break on function: location is #<id>#');
-  print('  break on script position: location is name:line[:column]');
-  print('clear <breakpoint #>');
-  print('backtrace [n] | [-n] | [from to]');
-  print('frame <frame #>');
+  print('Note: <> denotes symbollic values to be replaced with real values.');
+  print('Note: [] denotes optional parts of commands, or optional options / arguments.');
+  print('      e.g. d[elete] - you get the same command if you type d or delete.');
+  print('');
+  print('[break] - break as soon as possible');
+  print('b[reak] location [condition]');
+  print('        - break on named function: location is a function name');
+  print('        - break on function: location is #<id>#');
+  print('        - break on script position: location is name:line[:column]');
+  print('');
+  print('clear <breakpoint #>       - deletes the specified user defined breakpoint');
+  print('d[elete]  <breakpoint #>   - deletes the specified user defined breakpoint');
+  print('dis[able] <breakpoint #>   - disables the specified user defined breakpoint');
+  print('dis[able] exc[eptions] [[all] | unc[aught]]');
+  print('                           - disables breaking on exceptions');
+  print('en[able]  <breakpoint #>   - enables the specified user defined breakpoint');
+  print('en[able]  exc[eptions] [[all] | unc[aught]]');
+  print('                           - enables breaking on exceptions');
+  print('');
+  print('b[ack]t[race] [n] | [-n] | [from to]');
+  print('                           - prints the stack back trace');
+  print('f[rame]                    - prints info about the current frame context');
+  print('f[rame] <frame #>          - set context to specified frame #');
   print('scopes');
   print('scope <scope #>');
+  print('');
+  print('up                         - set context to caller of current frame');
+  print('do[wn]                     - set context to callee of current frame');
+  print('inf[o] br[eak]             - prints info about breakpoints in use');
+  print('inf[o] ar[gs]              - prints info about arguments of the current function');
+  print('inf[o] lo[cals]            - prints info about locals in the current function');
+  print('inf[o] liveobjectlist|lol  - same as \'lol info\'');
+  print('');
   print('step [in | next | out| min [step count]]');
-  print('print <expression>');
-  print('dir <expression>');
+  print('c[ontinue]                 - continue executing after a breakpoint');
+  print('s[tep]   [<N>]             - step into the next N callees (default N is 1)');
+  print('s[tep]i  [<N>]             - step into the next N callees (default N is 1)');
+  print('n[ext]   [<N>]             - step over the next N callees (default N is 1)');
+  print('fin[ish] [<N>]             - step out of N frames (default N is 1)');
+  print('');
+  print('p[rint] <expression>       - prints the result of the specified expression');
+  print('dir <expression>           - prints the object structure of the result');
+  print('set <var> = <expression>   - executes the specified statement');
+  print('');
+  print('l[ist]                     - list the source code around for the current pc');
+  print('l[ist] [- | <start>,<end>] - list the specified range of source code');
   print('source [from line [num lines]]');
-  print('scripts');
-  print('continue');
+  print('scr[ipts] [native|extensions|all]');
+  print('scr[ipts] [<filter text>]  - list scripts with the specified text in its description');
+  print('');
+  print('gc                         - runs the garbage collector');
+  print('');
   print('trace compile');
-  print('help');
+  // hidden command: trace debug json - toggles tracing of debug json packets
+  print('');
+  print('disconnect|exit|quit       - disconnects and quits the debugger');
+  print('help                       - prints this help information');
 }
 
 
@@ -930,6 +1325,27 @@
 }
 
 
+function refObjectToString_(protocolPackage, handle) {
+  var value = protocolPackage.lookup(handle);
+  var result = '';
+  if (value.isString()) {
+    result = '"' + value.value() + '"';
+  } else if (value.isPrimitive()) {
+    result = value.valueString();
+  } else if (value.isObject()) {
+    result += formatObject_(value, true);
+  }
+  return result;
+}
+
+
+// Rounds number 'num' to 'length' decimal places.
+function roundNumber(num, length) {
+  var factor = Math.pow(10, length);
+  return Math.round(num * factor) / factor;
+}
+
+
 // Convert a JSON response to text for display in a text based debugger.
 function DebugResponseDetails(response) {
   details = {text:'', running:false}
@@ -962,6 +1378,11 @@
         details.text = result;
         break;
 
+      case 'changebreakpoint':
+        result = 'successfully changed breakpoint';
+        details.text = result;
+        break;
+
       case 'listbreakpoints':
         result = 'breakpoints: (' + body.breakpoints.length + ')';
         for (var i = 0; i < body.breakpoints.length; i++) {
@@ -974,9 +1395,9 @@
           if (breakpoint.script_name) {
               result += ' script_name=' + breakpoint.script_name;
           }
-          result += ' line=' + breakpoint.line;
+          result += ' line=' + (breakpoint.line + 1);
           if (breakpoint.column != null) {
-            result += ' column=' + breakpoint.column;
+            result += ' column=' + (breakpoint.column + 1);
           }
           if (breakpoint.groupId) {
             result += ' groupId=' + breakpoint.groupId;
@@ -992,9 +1413,27 @@
           }
           result += ' hit_count=' + breakpoint.hit_count;
         }
+        if (body.breakpoints.length === 0) {
+          result = "No user defined breakpoints\n";
+        } else {
+          result += '\n';
+        }
+        if (body.breakOnExceptions) {
+          result += '* breaking on ALL exceptions is enabled\n';
+        } else if (body.breakOnUncaughtExceptions) {
+          result += '* breaking on UNCAUGHT exceptions is enabled\n';
+        } else {
+          result += '* all exception breakpoints are disabled\n';            
+        }
         details.text = result;
         break;
 
+      case 'setexceptionbreak':
+        result = 'Break on ' + body.type + ' exceptions: ';
+        result += body.enabled ? 'enabled' : 'disabled';
+        details.text = result;
+        break;
+
       case 'backtrace':
         if (body.totalFrames == 0) {
           result = '(empty stack)';
@@ -1010,10 +1449,39 @@
         break;
 
       case 'frame':
-        details.text = SourceUnderline(body.sourceLineText,
-                                       body.column);
-        Debug.State.currentSourceLine = body.line;
-        Debug.State.currentFrame = body.index;
+        if (last_cmd === 'info locals') {
+          var locals = body.locals;
+          if (locals.length === 0) {
+            result = 'No locals';
+          } else {
+            for (var i = 0; i < locals.length; i++) {
+              var local = locals[i];
+              result += local.name + ' = ';
+              result += refObjectToString_(response, local.value.ref);
+              result += '\n';
+            }
+          }
+        } else if (last_cmd === 'info args') {
+          var args = body.arguments;
+          if (args.length === 0) {
+            result = 'No arguments';
+          } else {
+            for (var i = 0; i < args.length; i++) {
+              var arg = args[i];
+              result += arg.name + ' = ';
+              result += refObjectToString_(response, arg.value.ref);
+              result += '\n';
+            }
+          }
+        } else {
+          result = SourceUnderline(body.sourceLineText,
+                                   body.column);
+          Debug.State.currentSourceLine = body.line;
+          Debug.State.currentFrame = body.index;
+          Debug.State.displaySourceStartLine = -1;
+          Debug.State.displaySourceEndLine = -1;
+        }
+        details.text = result;
         break;
 
       case 'scopes':
@@ -1132,7 +1600,9 @@
           if (body[i].name) {
             result += body[i].name;
           } else {
-            if (body[i].compilationType == Debug.ScriptCompilationType.Eval) {
+            if (body[i].compilationType == Debug.ScriptCompilationType.Eval
+                && body[i].evalFromScript
+                ) {
               result += 'eval from ';
               var script_value = response.lookup(body[i].evalFromScript.ref);
               result += ' ' + script_value.field('name');
@@ -1162,6 +1632,9 @@
           result += sourceStart;
           result += ']';
         }
+        if (body.length == 0) {
+          result = "no matching scripts found";
+        }
         details.text = result;
         break;
 
@@ -1181,6 +1654,23 @@
         details.text = "(running)";
         break;
 
+      case 'v8flags':
+        details.text = "flags set";
+        break;
+
+      case 'gc':
+        details.text = "GC " + body.before + " => " + body.after;
+        if (body.after > (1024*1024)) {
+          details.text +=
+              " (" + roundNumber(body.before/(1024*1024), 1) + "M => " +
+                     roundNumber(body.after/(1024*1024), 1) + "M)";
+        } else if (body.after > 1024) {
+          details.text +=
+              " (" + roundNumber(body.before/1024, 1) + "K => " +
+                     roundNumber(body.after/1024, 1) + "K)";
+        }
+        break;
+
       default:
         details.text =
             'Response for unknown command \'' + response.command() + '\'' +
@@ -1467,6 +1957,11 @@
 }
 
 
+ProtocolValue.prototype.valueString = function() {
+  return this.value_.text;
+}
+
+
 function ProtocolReference(handle) {
   this.handle_ = handle;
 }
@@ -1613,7 +2108,9 @@
       var property_value_json;
       switch (typeof property_value) {
         case 'object':
-          if (typeof property_value.toJSONProtocol == 'function') {
+          if (property_value === null) {
+            property_value_json = 'null';
+          } else if (typeof property_value.toJSONProtocol == 'function') {
             property_value_json = property_value.toJSONProtocol(true)
           } else if (property_value.constructor.name == 'Array'){
             property_value_json = SimpleArrayToJSON_(property_value);