[aliases] packaging up field aliasing

scripts/geodata/address_formatting/aliases.py

@@ -0,0 +1,26 @@
+import six
+from collections import defaultdict
+
+
+class Aliases(object):
+    def __init__(self, aliases):
+        self.aliases = aliases
+        self.priorities = {k: i for i, k in enumerate(aliases)}
+
+    def key_priority(self, key):
+        return self.priorities.get(key, len(self.priorities))
+
+    def replace(self, components):
+        replacements = defaultdict(list)
+        values = {}
+        for k in list(components):
+            new_key = self.aliases.get(k)
+            if new_key and new_key not in components:
+                value = components.pop(k)
+                values[k] = value
+                replacements[new_key].append(k)
+
+        for key, source_keys in six.iteritems(replacements):
+            source_keys.sort(key=self.key_priority)
+            value = values[source_keys[0]]
+            components[key] = value