diff --git a/platypush/message/event/__init__.py b/platypush/message/event/__init__.py
index 29d7606c3..d7a1f039c 100644
--- a/platypush/message/event/__init__.py
+++ b/platypush/message/event/__init__.py
@@ -97,10 +97,10 @@ class Event(Message):
                 'phrase': 'Hey dude turn on the living room lights'
             }
 
-            - self._matches_argument(argname='phrase', condition_value='Turn on the $lights lights')
+            - self._matches_argument(argname='phrase', condition_value='Turn on the ${lights} lights')
               will return EventMatchResult(is_match=True, parsed_args={ 'lights': 'living room' })
 
-            - self._matches_argument(argname='phrase', condition_value='Turn off the $lights lights')
+            - self._matches_argument(argname='phrase', condition_value='Turn off the ${lights} lights')
               will return EventMatchResult(is_match=False, parsed_args={})
         """
 
@@ -117,15 +117,14 @@ class Event(Message):
                 condition_tokens.pop(0)
                 result.score += 1
             elif re.search(condition_token, event_token):
-                # The only supported regex-match as of now is the equivalent of
-                # the maybe operator.
-                # e.g. "turn on (the)? lights" would match both "turn on the lights"
-                # and "turn on lights". In such a case, we just consume the
-                # condition token and proceed forward. TODO add a more
-                # sophisticated regex-match handling
+                m = re.search('({})'.format(condition_token), event_token)
+                if m.group(1):
+                    event_tokens.pop(0)
+                    result.score += 1
+
                 condition_tokens.pop(0)
             else:
-                m = re.match('[^\\\]*\$([\w\d_-]+)', condition_token)
+                m = re.match('[^\\\]*\${(.+?)}', condition_token)
                 if m:
                     argname = m.group(1)
                     if argname not in result.parsed_args:
diff --git a/platypush/message/request/__init__.py b/platypush/message/request/__init__.py
index d3854b781..c28eb9c51 100644
--- a/platypush/message/request/__init__.py
+++ b/platypush/message/request/__init__.py
@@ -88,22 +88,33 @@ class Request(Message):
         return event_args
 
 
-    def _expand_value_from_context(self, value, **context):
+    @classmethod
+    def _expand_value_from_context(cls, value, **context):
         parsed_value = ''
         while value:
-            m = re.match('([^\\\]*)\$([\w\d_-]+)(.*)', value)
-            if m:
-                context_argname = m.group(2)
-                value = m.group(3)
+            m = re.match('([^\$]*)(\${\s*(.+?)\s*})(.*)', value)
+            if m and not m.group(1).endswith('\\'):
+                prefix = m.group(1); expr = m.group(2);
+                inner_expr = m.group(3); value = m.group(4)
+
+                m = re.match('([^.\[\]()]+)(.*)', inner_expr)
+                context_argname = m.group(1)
+                path = m.group(2)
+
                 if context_argname in context:
-                    parsed_value += m.group(1) + context[context_argname]
-                else:
-                    parsed_value += m.group(1) + '$' + m.group(2)
+                    try:
+                        context_value = eval("context['{}']{}".format(
+                            context_argname, path if path else ''))
+                    except: context_value = expr
+
+                    parsed_value += prefix + str(context_value)
+                else: parsed_value += prefix + expr
             else:
                 parsed_value += value
                 value = ''
 
-        return parsed_value
+        try: return json.loads(parsed_value)
+        except ValueError as e: return parsed_value
 
 
     def _send_response(self, response):
@@ -126,16 +137,14 @@ class Request(Message):
             context -- Key-valued context. Example:
                 context = (group_name='Kitchen lights')
                 request.args:
-                    - group: $group_name  # will be expanded as "Kitchen lights")
+                    - group: ${group_name}  # will be expanded as "Kitchen lights")
         """
 
         def _thread_func(n_tries):
             if self.action.startswith('procedure.'):
-                try:
-                    response = self._execute_procedure(n_tries=n_tries)
-                finally:
-                    self._send_response(response)
-                    return response
+                response = self._execute_procedure(n_tries=n_tries)
+                self._send_response(response)
+                return response
             else:
                 (module_name, method_name) = get_module_and_method_from_action(self.action)
                 plugin = get_plugin(module_name)
diff --git a/platypush/procedure/__init__.py b/platypush/procedure/__init__.py
index 5e9cf950e..ef2322ca7 100644
--- a/platypush/procedure/__init__.py
+++ b/platypush/procedure/__init__.py
@@ -54,8 +54,10 @@ class Procedure(object):
                 request.execute(n_tries, async=True, **context)
             else:
                 response = request.execute(n_tries, async=False, **context)
-                context = { k:v for (k,v) in response.output.items() } \
-                    if isinstance(response.output, dict) else {}
+
+                if isinstance(response.output, dict):
+                    for (k,v) in response.output.items():
+                        context[k] = v
 
                 context['output'] = response.output
                 context['errors'] = response.errors
diff --git a/tests/test_event_parse.py b/tests/test_event_parse.py
index 8f0a7ba46..42c67f3e2 100644
--- a/tests/test_event_parse.py
+++ b/tests/test_event_parse.py
@@ -9,7 +9,7 @@ class TestEventParse(unittest.TestCase):
     def setUp(self):
         self.condition = EventCondition.build({
             'type': 'platypush.message.event.ping.PingEvent',
-            'message': 'This is (the)? answer: $answer'
+            'message': 'This is (the)? answer: ${answer}'
         })
 
     def test_event_parse(self):