Add "implemented_in" key in IDL schema compiler

tools/json_schema_compiler/idl_schema.py

Index: tools/json_schema_compiler/idl_schema.py
diff --git a/tools/json_schema_compiler/idl_schema.py b/tools/json_schema_compiler/idl_schema.py
index 238fb05e3ce5b388a8c776bd4942f5984801269a..f7959847420eb1496a26ef819b79be522f5eacd3 100644
--- a/tools/json_schema_compiler/idl_schema.py
+++ b/tools/json_schema_compiler/idl_schema.py
@@ -324,11 +324,13 @@ class Namespace(object):
                description,
                nodoc=False,
                internal=False,
-               platforms=None):
+               platforms=None,
+               compiler_options=None):
     self.namespace = namespace_node
     self.nodoc = nodoc
     self.internal = internal
     self.platforms = platforms
+    self.compiler_options = compiler_options
     self.events = []
     self.functions = []
     self.types = []
@@ -357,7 +359,9 @@ class Namespace(object):
             'functions': self.functions,
             'internal': self.internal,
             'events': self.events,
-            'platforms': self.platforms}
+            'platforms': self.platforms,
+            'compiler_options': {}
+               if not self.compiler_options else self.compiler_options}

[sergeygs, 2013/11/02 06:20:44]

I'd prefer:

'compiler_options': self.compiler_options or {}

It's a common idiom in Python and it's a lot simpler. Also, conditional
expressions are restricted to one-liners in Google guide, while you have 2 lines

(https://engdoc.corp.google.com/eng/doc/pyguide.xml?showone=Conditional_Expres...)

[Haojian Wu, 2013/11/03 01:56:16]

Done.

[not at google - send to devlin, 2013/11/04 15:16:49]

The problem with "self.compiler_options or {}" is that the behaviour subtly
changes if self._compiler_options is an empty object (vs None), because bool({})
is false. This is why being explicit in the object case is every-so-slighly
safer, generally speaking. "foo or Foo()" is great when bool(Foo()) is true.

If the two-line-conditional is a problem then assign it outside the loop.

 
   def process_interface(self, node):
     members = []
@@ -383,6 +387,7 @@ class IDLSchema(object):
     internal = False
     description = None
     platforms = None
+    compiler_options = None
     for node in self.idl:
       if node.cls == 'Namespace':
         if not description:
@@ -390,11 +395,13 @@ class IDLSchema(object):
           print('%s must have a namespace-level comment. This will '
                            'appear on the API summary page.' % node.GetName())
           description = ''
-        namespace = Namespace(node, description, nodoc, internal, platforms)
+        namespace = Namespace(node, description, nodoc, internal,
+            platforms=platforms, compiler_options=compiler_options)

[sergeygs, 2013/11/02 06:20:44]

Align 'platform...' with 'node' in the preceding line. I think you will also
have to move 'compiler_options' to new line then as well. Google style guide is
silent about this, but PEP 8 is explicit:
http://www.python.org/dev/peps/pep-0008/#indentation.

[Haojian Wu, 2013/11/03 01:56:16]

Done. Thanks for the link.

         namespaces.append(namespace.process())
         nodoc = False
         internal = False
         platforms = None
+        compiler_options = None
       elif node.cls == 'Copyright':
         continue
       elif node.cls == 'Comment':
@@ -406,6 +413,8 @@ class IDLSchema(object):
           internal = bool(node.value)
         elif node.name == 'platforms':
           platforms = list(node.value)
+        elif node.name == 'implemented_in':
+          compiler_options = {"implemented_in": node.value}

[sergeygs, 2013/11/02 06:20:44]

Please use single quotes here: { 'implemented_in': node.value }. It's a frequent
Python convention to use double quotes for plain language and/or interpolated
strings, and single quotes for identifiers that would result in a logical or
runtime error if misspelled. I can't say we stick to that in our code, but if
anything, we favor single quotes, specifically in the surrounding code in this
file and others in this CL.

[Haojian Wu, 2013/11/03 01:56:16]

Done. Thanks for the detailed explainations.

         else:
           continue
       else: