Initial commit of the Dart Chrome Extension APIs generators

tools/json_schema_compiler/code.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 class Code(object):
   """A convenience object for constructing code.
 
   Logically each object should be a block of code. All methods except |Render|
   and |IsEmpty| return self.
   """
@@ skipping 45 matching lines @@
 
     return self
 
   def Cblock(self, code):
     """Concatenates another Code object |code| onto this one followed by a
     blank line, if |code| is non-empty."""
     if not code.IsEmpty():
       self.Concat(code).Append()
     return self
 
-  def Sblock(self, line=''):
+  def Sblock(self, line=None):
     """Starts a code block.
 
     Appends a line of code and then increases the indent level.
     """
-    self.Append(line)
+    if line is not None:
+      self.Append(line)
     self._indent_level += self._indent_size
     return self
 
-  def Eblock(self, line=''):
+  def Eblock(self, line=None):
     """Ends a code block by decreasing and then appending a line (or a blank
     line if not given).
     """
     # TODO(calamity): Decide if type checking is necessary
     #if not isinstance(line, basestring):
     #  raise TypeError
     self._indent_level -= self._indent_size
-    self.Append(line)
+    if line is not None:
+      self.Append(line)
     return self
 
   def Comment(self, comment, comment_prefix='// '):
     """Adds the given string as a comment.
 
     Will split the comment if it's too long. Use mainly for variable length
     comments. Otherwise just use code.Append('// ...') for comments.
 
     Unaffected by code.Substitute().
     """
@@ skipping 36 matching lines @@
     """Renders Code as a string.
     """
     return '\n'.join([l.value for l in self._code])
 
 class Line(object):
   """A line of code.
   """
   def __init__(self, value, substitute=True):
     self.value = value
     self.substitute = substitute