keep track of current frame. eval works for global scope

lib/_debugger.js

@@ -110,7 +110,7 @@ Protocol.prototype.serialize = function(req) {
 };
 
 
-
+var NO_FRAME = -1;
 
 function Client() {
   net.Stream.call(this);
@@ -118,6 +118,9 @@ function Client() {
   this._reqCallbacks = [];
   var socket = this;
 
+  this.currentFrame = NO_FRAME;
+  this.currentSourceLine = -1;
+
   // Note that 'Protocol' requires strings instead of Buffers.
   socket.setEncoding('utf8');
   socket.on('data', function(d) {
@@ -142,7 +145,7 @@ Client.prototype._onResponse = function(res) {
     this._reqCallbacks.splice(i, 1);
     cb(res.body);
   } else {
-    console.error("unhandled res: %j", res.body);
+    this.emit('unhandledResponse', res.body);
   }
 };
 
@@ -161,7 +164,30 @@ Client.prototype.reqVersion = function(cb) {
 };
 
 
-var helpMessage = "Commands: version, eval, help, quit";
+Client.prototype.reqEval = function(expression, cb) {
+  var req = {
+    command: 'evaluate',
+    arguments: { expression: expression }
+  };
+
+  if (this.currentFrame == NO_FRAME) req.arguments.global = true;
+
+  this.req(req, function (res) {
+    if (cb) cb(res.body);
+  });
+};
+
+
+// reqBacktrace(cb)
+// TODO: from, to, bottom
+Client.prototype.reqBacktrace = function(cb) {
+  this.req({ command: 'backtrace' } , function (res) {
+    if (cb) cb(res.body);
+  });
+};
+
+
+var helpMessage = "Commands: backtrace, version, eval, help, quit";
 
 
 function startInterface() {
@@ -194,13 +220,14 @@ function startInterface() {
         i.prompt();
       });
 
-    } else if (/^eval/.test(cmd)) {
-      var req = {
-        command: 'evaluate',
-        arguments: { 'expression': cmd.slice(5) }
-      };
+    } else if ('backtrace' == cmd || 'bt' == cmd) {
+      c.reqBacktrace(function (bt) {
+        console.log(bt);
+        i.prompt();
+      });
 
-      c.req(req, function (res) {
+    } else if (/^eval/.test(cmd)) {
+      c.reqEval(cmd.slice(5), function (res) {
         console.log(res);
         i.prompt();
       });
@@ -214,6 +241,12 @@ function startInterface() {
     }
   });
 
+  c.on('unhandledResponse', function (res) {
+    console.log("\r\nunhandled res:");
+    console.log(res.body);
+    i.prompt();
+  });
+
   i.on('close', function() {
     stdin.destroy();
   });