Mock up code completion.

dart/site/try/src/editor.dart

Index: dart/site/try/src/editor.dart
diff --git a/dart/site/try/src/editor.dart b/dart/site/try/src/editor.dart
index 885295de9c167a69860620832964cdb048f71f0c..47fa0df7a5dc79b9b978bc9d4c2e24fedbe97221 100644
--- a/dart/site/try/src/editor.dart
+++ b/dart/site/try/src/editor.dart
@@ -6,6 +6,12 @@ library trydart.editor;
 
 import 'dart:html';
 
+import 'dart:async' show
+    Timer;
+
+import 'dart:convert' show
+    JSON;
+
 import '../../../sdk/lib/_internal/compiler/implementation/scanner/scannerlib.dart'
   show
     EOF_TOKEN,
@@ -19,6 +25,7 @@ import 'compilation.dart' show
     scheduleCompilation;
 
 import 'ui.dart' show
+    applyingSettings,
     currentTheme,
     hackDiv,
     inputPre,
@@ -26,6 +33,7 @@ import 'ui.dart' show
     outputDiv;
 
 import 'decoration.dart' show
+    CodeCompletionDecoration,
     Decoration,
     DiagnosticDecoration,
     error,
@@ -34,7 +42,17 @@ import 'decoration.dart' show
 
 const String INDENT = '\u{a0}\u{a0}';
 
+Set<String> seenIdentifiers;
+
 onKeyUp(KeyboardEvent e) {
+  scheduleCodeCompletion();
+
+  if (e.keyCode == 40 && activeCompletion != null) {
+    e.preventDefault();
+    print('${e.keyCode}: ${e}');
+    return;
+  }
+
   if (e.keyCode == 13) {
     e.preventDefault();
     Selection selection = window.getSelection();
@@ -51,16 +69,94 @@ onKeyUp(KeyboardEvent e) {
   hackDiv = newDiv;
 }
 
+Timer codeCompletionTimer;
+
+void scheduleCodeCompletion() {
+  if (applyingSettings) return;
+  if (codeCompletionTimer != null) {
+    codeCompletionTimer.cancel();
+    codeCompletionTimer = null;
+  }
+  codeCompletionTimer =
+      new Timer(const Duration(milliseconds: 1), displayCodeCompletion);
+}
+
+var activeCompletion;
+
+void displayCodeCompletion() {
+  if (activeCompletion != null) {
+    activeCompletion.classes.remove('active');
+    activeCompletion = null;
+  }
+  Selection selection = window.getSelection();
+  if (!selection.isCollapsed) return;
+  var anchorNode = selection.anchorNode;
+  if (!inputPre.contains(anchorNode)) return;
+  int anchorOffset = selection.anchorOffset;
+  int type = anchorNode.nodeType;
+  if (type != Node.TEXT_NODE) return;
+  Text text = anchorNode;
+  var parent = text.parent;
+  if (parent is! Element) return;
+  parent.classes.add('active');
+  var ui = parent.query('.dart-code-completion');
+  if (ui == null) return;
+  activeCompletion = parent;
+  observer.disconnect();
+  ui.nodes.clear();
+  String prefix = text.data.substring(0, anchorOffset).trim();
+  if (!prefix.isEmpty) {
+    String encodedArg0 = Uri.encodeComponent('"$prefix"');
+    String mindQuery =
+        'http://dart-mind.appspot.com/rpc'
+        '?action=GetExportingPubCompletions'
+        '&arg0=$encodedArg0';
+    HttpRequest request = new HttpRequest();
+    request.open('GET', mindQuery, async: false);
+    try {
+      List<String> response = <String>[];
+      var sw = new Stopwatch();
+      if (false) {
+        sw.start();
+        request.send();
+        sw.stop();
+        if (request.status == 200) {
+          response = JSON.decode(request.responseText);
+        }
+      } else {
+        sw.start();
+        response =
+            seenIdentifiers.where(
+                (String identifier) => identifier != prefix && identifier.startsWith(prefix))

[kasperl, 2014/03/13 07:39:58]

Long line.

+            .toList(growable: false)
+            ..sort();

[kasperl, 2014/03/13 07:39:58]

I think I'd prefer to not use .. for this. It's a lot harder to understand than
a separate line with response.sort().

+        sw.stop();
+      }
+      response.forEach((String completion) {
+        ui.appendHtml('$completion<br>');
+      });
+      ui.appendHtml('${sw.elapsedMilliseconds}ms<br>');
+    } catch (e) {
+      window.console.dir(e);
+    }
+  }
+  observer.observe(inputPre, childList: true, characterData: true, subtree: true);

[kasperl, 2014/03/13 07:39:58]

Long line.

+}
+
 bool isMalformedInput = false;
 String currentSource = "";
 
 // TODO(ahe): This method should be cleaned up. It is too large.
 onMutation(List<MutationRecord> mutations, MutationObserver observer) {
-  scheduleCompilation();
+  // scheduleCompilation();
 
-  for (Element element in inputPre.queryAll('a[class="diagnostic"]>span')) {
+  for (Element element in inputPre.queryAll('a.diagnostic>span')) {
+    element.remove();
+  }
+  for (Element element in inputPre.queryAll('.dart-code-completion')) {
     element.remove();
   }
+
   // Discard clean-up mutations.
   observer.takeRecords();
 
@@ -181,6 +277,7 @@ onMutation(List<MutationRecord> mutations, MutationObserver observer) {
     Token token = new StringScanner(
         new StringSourceFile('', text), includeComments: true).tokenize();
     int offset = 0;
+    seenIdentifiers = new Set<String>();
     for (;token.kind != EOF_TOKEN; token = token.next) {
       Decoration decoration = getDecoration(token);
       if (decoration == null) continue;
@@ -213,6 +310,14 @@ onMutation(List<MutationRecord> mutations, MutationObserver observer) {
 
   window.localStorage['currentSource'] = currentSource;
 
+  if (activeCompletion != null) {
+    if (codeCompletionTimer != null) {
+      codeCompletionTimer.cancel();
+      codeCompletionTimer = null;
+    }
+    displayCodeCompletion();
+  }
+
   // Discard highlighting mutations.
   observer.takeRecords();
 }
@@ -295,7 +400,12 @@ Decoration getDecoration(Token token) {
   String tokenValue = token.value;
   String tokenInfo = token.info.value;
   if (tokenInfo == 'string') return currentTheme.string;
-  // if (tokenInfo == 'identifier') return identifier;
+  if (tokenInfo == 'identifier') {
+    seenIdentifiers.add(tokenValue);
+
+    print(seenIdentifiers);
+    return CodeCompletionDecoration.from(currentTheme.foreground);
+  }
   if (tokenInfo == 'keyword') return currentTheme.keyword;
   if (tokenInfo == 'comment') return currentTheme.singleLineComment;
   if (tokenInfo == 'malformed input') {