handle reserved words used as dictionary keys

namedtupled/namedtupled.py

@@ -1,7 +1,10 @@
+import keyword
+import builtins
 from future import standard_library
 standard_library.install_aliases()
 from collections import Mapping, namedtuple, UserDict
 
+RESERVED = keyword.kwlist + dir(builtins)
 
 def mapper(mapping, _nt_name='NT'):
     """ Convert mappings to namedtuples recursively. """
@@ -15,6 +18,15 @@ def mapper(mapping, _nt_name='NT'):
 
 
 def namedtuple_wrapper(_nt_name, **kwargs):
+    for k in kwargs:
+        if k in RESERVED:
+            new_k = k + '_'
+            val = kwargs.pop(k)
+            if new_k in kwargs:
+                msg = "Can't rename the field {} to {}. {} already exist"
+                raise ValueError(msg.format(k, new_k, new_k))
+            kwargs.update({new_k: val})
+
     wrap = namedtuple(_nt_name, kwargs)
     return wrap(**kwargs)
 

tests/test_map.py

@@ -17,6 +17,17 @@
 
 mapping_array = [mapping, mapping]
 
+mapping_keywords = {
+    'baz': 'bar',
+    'from': 'John Doe'
+}
+
+mapping_keywords_dup = {
+    'baz': 'bar',
+    'from': 'John Doe',
+    'from_': 'Acme Corp'
+}
+
 
 def test_namedtupled_map_object(mapping=mapping):
     t = namedtupled.map(mapping)
@@ -43,3 +54,20 @@ def test_namedtupled_map_array(mapping=mapping_array):
     assert t[0].alist[1].two == '2'
     assert t[0].baz != {'qux': 'quux'}
     assert t[0].alist[0] != {'one': '1', 'a': 'A'}
+
+
+def test_namedtupled_map_object_keywords(mapping=mapping_keywords):
+    try:
+        t = namedtupled.map(mapping)
+    except ValueError:
+        # Type names and field names cannot be a keyword: 'from'
+        assert False
+
+    assert t.from_ == 'John Doe'
+    assert len(t._fields) == len(mapping)
+
+def test_namedtupled_map_object_keywords_dup(mapping=mapping_keywords_dup):
+    try:
+        t = namedtupled.map(mapping)
+    except ValueError:
+        assert True