Refactor code to prepare for line-based tokenization.

dart/site/try/src/html_to_text.dart

 // Copyright (c) 2014, 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 trydart.htmlToText;
 
 import 'dart:math' show
     max;
 
-import 'dart:html';
+import 'dart:html' show
+    Element,
+    Node,
+    NodeFilter,
+    Text,
+    TreeWalker;
+
+import 'selection.dart' show
+    TrySelection;
 
 /// Returns true if [node] is a block element, that is, not inline.
 bool isBlockElement(Node node) {
   if (node is! Element) return false;
   Element element = node;
   return element.getComputedStyle().display != 'inline';
 }
 
 /// Position [walker] at the last predecessor (that is, child of child of
 /// child...) of [node]. The next call to walker.nextNode will return the first
 /// node after [node].
 void skip(Node node, TreeWalker walker) {
   if (walker.nextSibling() != null) {
     walker.previousNode();
     return;
   }
   for (Node current = walker.nextNode();
        current != null;
        current = walker.nextNode()) {
     if (!node.contains(current)) {
       walker.previousNode();
       return;
     }
   }
 }
 
 /// Writes the text of [root] to [buffer]. Keeps track of [selection] and
 /// returns the new anchorOffset from beginning of [buffer] or -1 if the
 /// selection isn't in [root].
-int htmlToText(Node root, StringBuffer buffer, Selection selection) {
+int htmlToText(Node root, StringBuffer buffer, TrySelection selection) {
   int selectionOffset = -1;
   TreeWalker walker = new TreeWalker(root, NodeFilter.SHOW_ALL);
 
   for (Node node = root; node != null; node = walker.nextNode()) {
     switch (node.nodeType) {
       case Node.CDATA_SECTION_NODE:
       case Node.TEXT_NODE:
-        if (selection.isCollapsed && selection.anchorNode == node) {
+        if (selection.anchorNode == node) {
           selectionOffset = selection.anchorOffset + buffer.length;
         }
         Text text = node;
         buffer.write(text.data.replaceAll('\xA0', ' '));
         break;
 
       default:
         if (node.nodeName == 'BR') {
           buffer.write('\n');
         } else if (node != root && isBlockElement(node)) {
           selectionOffset =
               max(selectionOffset, htmlToText(node, buffer, selection));
           skip(node, walker);
         }
         break;
     }
   }
 
   if (isBlockElement(root)) {
     buffer.write('\n');
   }
 
   return selectionOffset;
 }