metaprogramming examples

metaprog/oscon-schedule/schedule2.py

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+import warnings
+import inspect
+
+from explore import load_json
+
+DB_NAME = 'schedule2_db'
+CONFERENCE = 'conference.115'
+
+
+class Record:
+    def __init__(self, mapping):
+        self.__dict__.update(mapping)
+
+    def __eq__(self, other):
+        if isinstance(other, Record):
+            return self.__dict__ == other.__dict__
+        else:
+            return NotImplemented
+
+    def __repr__(self):
+        if hasattr(self, 'name'):
+            ident = repr(self.name)
+        else:
+            ident = 'object at ' + hex(id(self))
+        cls_name = self.__class__.__name__
+        return '<{} {}>'.format(cls_name, ident)
+
+
+class Event(Record):
+
+    @classmethod
+    def set_db(cls, db):
+        cls._db = db
+
+    @property
+    def venue(self):
+        key = self.venue_serial
+        return self._db['venue.{}'.format(key)]
+
+    @property
+    def speakers(self):
+        spkr_serials = self.__dict__['speakers']
+        if not hasattr(self, '_speaker_refs'):
+            self._speaker_refs = [self._db['speaker.{}'.format(key)]
+                                  for key in spkr_serials]
+        return self._speaker_refs
+
+
+def load_db(db):
+    raw_data = load_json()
+    warnings.warn('loading ' + DB_NAME)
+    for collection, rec_list in raw_data['Schedule'].items():
+        rec_type = collection[:-1]
+        for fields in rec_list:
+            cls_name = rec_type.capitalize()
+            cls = globals().get(cls_name, Record)
+            if inspect.isclass(cls) and issubclass(cls, Record):
+                record = cls(fields)
+            else:
+                Record(fields)
+            key = '{}.{}'.format(rec_type, fields['serial'])
+            db[key] = record