Improve the instance-view page in observatory.

runtime/bin/vmservice/client/lib/src/elements/eval_box.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library eval_box_element;
+
+import 'dart:async';
+import 'dart:html';
+import 'observatory_element.dart';
+import 'package:polymer/polymer.dart';
+
+
+typedef Future<ObservableMap> evalType(String text);
+
+
+@CustomTag('eval-box')
+class EvalBoxElement extends ObservatoryElement {
+  @observable String text;
+  @observable String lineMode = "1-line";
+
+  @published evalType callback;
+  @observable ObservableList results = toObservable([]);
+
+  void updateLineMode(Event e, var detail, Node target) {
+    lineMode = (e.target as InputElement).value;
+    if (lineMode == '1-line') {
+      text = text.replaceAll('\n', ' ');
+    }
+  }
+
+  void eval(Event e, var detail, Node target) {
+    // Prevent any form action.
+    e.preventDefault();
+
+    // Clear the text box.
+    var expr = text;
+    text = '';
+
+    // Use provided callback to eval the expression.
+    if (callback != null) {
+      var map = toObservable({});
+      map['expr'] = expr;
+      results.insert(0, map);
+      callback(expr).then((result) {
+          map['value'] = result;
+      });
+    }
+  }
+
+  void selectExpr(MouseEvent e) {
+    assert(e.target is Element);
+    Element targetElement = e.target;
+    text = targetElement.getAttribute('expr');
+  }
+
+  EvalBoxElement.created() : super.created();
+}