nirum-lang · kanghyojun · Mar 20, 2017 · Mar 19, 2017 · Mar 19, 2017 · Mar 20, 2017
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -11,5 +11,7 @@ To be released.
 - Added :mod:`nirum.datastructures` module and
   :class:`~nirum.datastructures.Map` which is an immutable dictionary.
   [:issue:`66`]
+- Added :class:`nirum.datastructures.List` which is an immutable list.
+  [:issue:`49`]
 
 __ https://github.com/spoqa/nirum/blob/f1629787f45fef17eeab8b4f030c34580e0446b8/docs/serialization.md
diff --git a/nirum/datastructures.py b/nirum/datastructures.py
@@ -6,7 +6,7 @@
 """
 import collections
 
-__all__ = 'Map',
+__all__ = 'List', 'Map'
 
 
 class Map(collections.Mapping):
@@ -49,3 +49,27 @@ def __repr__(self):
         else:
             args = ''
         return '{0.__module__}.{0.__name__}({1})'.format(type(self), args)
+
+
+class List(collections.Sequence):
+
+    def __init__(self, l):
+        self.l = l
+
+    def __getitem__(self, index):
+        return self.l[index]
+
+    def __len__(self):
+        return len(self.l)
+
+    def __contains__(self, item):
+        return item in self.l
+
+    def __iter__(self):
+        return iter(self.l)
+
+    def index(self, item):
+        return self.l.index(item)
+
+    def count(self, item):
+        return self.l.count(item)
diff --git a/nirum/deserialize.py b/nirum/deserialize.py
@@ -13,8 +13,8 @@
 from iso8601 import iso8601, parse_date
 from six import text_type
 
-from ._compat import get_tuple_param_types, get_union_types, is_union_type
 from .datastructures import Map
+from ._compat import get_tuple_param_types, get_union_types, is_union_type
 
 __all__ = (
     'deserialize_abstract_type',

diff --git a/tests/datastructures_test.py b/tests/datastructures_test.py
@@ -3,7 +3,7 @@
 
 from pytest import raises
 
-from nirum.datastructures import Map
+from nirum.datastructures import List, Map
 
 
 def test_map_init():
@@ -68,3 +68,23 @@ def test_map_repr():
     assert repr(Map()) == 'nirum.datastructures.Map()'
     assert repr(Map(a=1)) == "nirum.datastructures.Map({'a': 1})"
     assert repr(Map(a=1, b=2)) == "nirum.datastructures.Map({'a': 1, 'b': 2})"
+
+
+def test_list():
+    immutable_list = List([1, 2])
+    with raises(AttributeError):
+        immutable_list.append(1)
+
+    with raises(TypeError):
+        immutable_list + [3]
+
+    assert isinstance(immutable_list, collections.Sequence)
+    assert not isinstance(immutable_list, collections.MutableSequence)
+    assert immutable_list[0] == 1
+    assert len(immutable_list) == 2
+    assert 2 in immutable_list
+    assert next(iter(immutable_list)) == 1
+    assert immutable_list.index(2) == 1
+    assert immutable_list.count(1) == 1
+    assert immutable_list.count(2) == 1
+    assert immutable_list.count(3) == 0