Formatter checkpoint.

pkg/analyzer_experimental/lib/src/services/writer.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 source_writer;
 
 
 class Line {
 
   final int lineLength;
@@ skipping 15 matching lines @@
   addSpaces(int n) {
     if (n > 0) {
       tokens.add(new SpaceToken(n));
     }
   }
 
   addToken(LineToken token) {
     tokens.add(token);
   }
 
+  bool isWhitespace() {
+    for (var tok in tokens) {
+      if (!(tok is SpaceToken)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   _indent(int n) {
     tokens.add(useTabs ? new TabToken(n) : new SpaceToken(n * spacesPerIndent));
   }
 
   String toString() {
     var buffer = new StringBuffer();
     for (var tok in tokens) {
       buffer.write(tok.toString());
     }
     return buffer.toString();
@@ skipping 47 matching lines @@
 
   unindent() {
     --indentCount;
   }
 
   print(x) {
     currentLine.addToken(new LineToken(x));
   }
 
   newline() {
+    if (currentLine.isWhitespace()) {
+      currentLine.tokens.clear();
+    }
     currentLine.addToken(new NewlineToken(this.lineSeparator));
     buffer.write(currentLine.toString());
     currentLine = new Line(indent: indentCount);
   }
 
+  newlines(int num) {
+    while (num-- > 0) {
+      newline();
+    }
+  }
+
   space() {
     spaces(1);
   }
 
   spaces(n) {
     currentLine.addSpaces(n);
   }
 
   println(String s) {
     print(s);
     newline();
   }
 
   String toString() {
     var source = new StringBuffer(buffer.toString());
-    source.write(currentLine);
+    if (!currentLine.isWhitespace()) {
+      source.write(currentLine);
+    }
     return source.toString();
   }
+
 }
 
 
 const SPACE = ' ';
 final SPACES = [
           '',
           ' ',
           '  ',
           '   ',
           '    ',
@@ skipping 36 matching lines @@
 
 String getTabs(int n) => n < TABS.length ? TABS[n] : repeat('\t', n);
 
 String repeat(String ch, int times) {
   var sb = new StringBuffer();
   for (var i = 0; i < times; ++i) {
     sb.write(ch);
   }
   return sb.toString();
 }