Make the properties list JSON and add some more info.

components/style/list_properties.py

@@ -1,14 +1,24 @@
-#!/bin/env python2.7
+#!/usr/bin/env python
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 import os.path
 import sys
+import json
 
 style = os.path.dirname(__file__)
 sys.path.insert(0, os.path.join(style, "Mako-0.9.1.zip"))
-
 from mako.template import Template
+
 template = Template(filename=os.path.join(style, "properties.mako.rs"), input_encoding='utf8')
 template.render()
-properties = template.module.LONGHANDS + template.module.SHORTHANDS
+properties = dict(
-for name in sorted(p.name for p in properties):
+    (p.name, {
-    print(name)
+        "flag": p.experimental,
+        "shorthand": hasattr(p, "sub_properties")
+    })
+    for p in template.module.LONGHANDS + template.module.SHORTHANDS
+)
+print(json.dumps(properties, indent=4))

python/servo/testing_commands.py

@@ -15,6 +15,7 @@ import sys
 import os
 import os.path as path
 import subprocess
+import json
 from collections import OrderedDict
 from time import time
 
@@ -158,10 +159,10 @@ class MachCommands(CommandBase):
     @CommandArgument('test_name', nargs=argparse.REMAINDER,
                      help="Only run tests that match this pattern or file path")
     def test_unit(self, test_name=None, package=None):
-        properties = subprocess.check_output([
+        properties = json.loads(subprocess.check_output([
             sys.executable,
             path.join(self.context.topdir, "components", "style", "list_properties.py")
-        ]).splitlines()
+        ]))
         assert len(properties) >= 100
         assert "margin-top" in properties
         assert "margin" in properties