updated from Atlas

19-dyn-attr-prop/oscon/explore1.py

@@ -0,0 +1,78 @@
+"""
+explore1.py: Script to explore the OSCON schedule feed
+
+    >>> from osconfeed import load
+    >>> raw_feed = load()
+    >>> feed = FrozenJSON(raw_feed)
+    >>> len(feed.Schedule.speakers)
+    357
+    >>> sorted(feed.Schedule.keys())
+    ['conferences', 'events', 'speakers', 'venues']
+    >>> for key, value in sorted(feed.Schedule.items()):
+    ...     print('{:3} {}'.format(len(value), key))
+    ...
+      1 conferences
+    484 events
+    357 speakers
+     53 venues
+    >>> feed.Schedule.speakers[-1].name
+    'Carina C. Zona'
+    >>> talk = feed.Schedule.events[40]
+    >>> type(talk)
+    <class 'explore1.FrozenJSON'>
+    >>> talk.name
+    'There *Will* Be Bugs'
+    >>> talk.speakers
+    [3471, 5199]
+    >>> talk.flavor
+    Traceback (most recent call last):
+      ...
+    KeyError: 'flavor'
+
+Handle keywords by appending a `_`.
+
+# BEGIN EXPLORE1_DEMO
+
+    >>> grad = FrozenJSON({'name': 'Jim Bo', 'class': 1982})
+    >>> grad.name
+    'Jim Bo'
+    >>> grad.class_
+    1991
+
+# END EXPLORE1_DEMO
+
+"""
+
+from collections import abc
+import keyword
+
+
+class FrozenJSON:
+    """A read-only façade for navigating a JSON-like object
+       using attribute notation
+    """
+
+# BEGIN EXPLORE1
+    def __init__(self, mapping):
+        self.__data = {}
+        for key, value in mapping.items():
+            if keyword.iskeyword(key):  # <1>
+                key += '_'
+            self.__data[key] = value
+# END EXPLORE1
+
+    def __getattr__(self, name):
+        if hasattr(self.__data, name):
+            return getattr(self.__data, name)
+        else:
+            return FrozenJSON.build(self.__data[name])
+
+    @classmethod
+    def build(cls, obj):
+        if isinstance(obj, abc.Mapping):
+            return cls(obj)
+        elif isinstance(obj, abc.MutableSequence):
+            return [cls.build(item) for item in obj]
+        else:  # <8>
+            return obj
+