add method propOr

README.md

@@ -566,7 +566,7 @@ R.propEq(1, 'v1', {'v1': 1}) # True
 ```
 
 - [ ] propIs
-- [ ] propOr
+- [x] propOr
 - [x] 0.1.2 props
 - [ ] propSatisfies
 - [x] 0.1.2 range

ramda/__init__.py

@@ -86,6 +86,7 @@
 from .project import project
 from .prop import prop
 from .propEq import propEq
+from .propOr import propOr
 from .props import props
 from .range import range
 from .reduce import reduce

ramda/propOr.py

@@ -0,0 +1,5 @@
+from .defaultTo import defaultTo
+from .private._curry3 import _curry3
+from .prop import prop
+
+propOr = _curry3(lambda val, p, obj: defaultTo(val, prop(p, obj)))

test/test_propOr.py

@@ -0,0 +1,69 @@
+
+import unittest
+
+import ramda as R
+
+"""
+https://github.com/ramda/ramda/blob/master/test/propOr.js
+"""
+
+fred = {'name': 'Fred', 'age': 23}
+anon = {'age': 99}
+
+nm = R.propOr('Unknown', 'name')
+
+class TestPropOrForDict(unittest.TestCase):
+  def test_returns_a_function_that_fetches_the_appropriate_property(self):
+    self.assertEqual('Fred', nm(fred))
+
+  def test_returns_the_default_value_when_the_property_does_not_exist(self):
+    self.assertEqual('Unknown', nm(anon))
+
+  def test_returns_the_default_value_when_the_object_is_None(self):
+    self.assertEqual('Unknown', nm(None))
+
+  def test_uses_the_default_when_supplied_an_object_with_a_None_value(self):
+    self.assertEqual('foo', R.propOr('foo', 'x', {'x': None}))
+
+class Fred:
+  def __init__(self):
+    self.name = 'Fred'
+    self.age = 23
+fredObj = Fred()
+
+class Anon:
+  def __init__(self):
+    self.age = 99
+anonObj = Anon()
+
+class TestPropOrForObject(unittest.TestCase):
+  def test_returns_a_function_that_fetches_the_appropriate_property(self):
+    self.assertEqual('Fred', nm(fredObj))
+
+  def test_returns_the_default_value_when_the_property_does_not_exist(self):
+    self.assertEqual('Unknown', nm(anonObj))
+
+  def test_returns_the_default_value_when_the_object_is_None(self):
+    self.assertEqual('Unknown', nm(None))
+
+  def test_uses_the_default_when_supplied_an_object_with_a_None_value(self):
+    class NoneObj:
+      def __init__(self):
+        self.x = None
+    self.assertEqual('foo', R.propOr('foo', 'x', NoneObj()))
+
+class TestPropOtherCases(unittest.TestCase):
+  def test_handles_number_as_property(self):
+    deities = ['Cthulhu', 'Dagon', 'Yog-Sothoth']
+    self.assertEqual('Cthulhu', R.propOr('Unknown', 0, deities))
+    self.assertEqual('Dagon', R.propOr('Unknown', 1, deities))
+    self.assertEqual('Yog-Sothoth', R.propOr('Unknown', 2, deities))
+    self.assertEqual('Yog-Sothoth', R.propOr('Unknown', -1, deities))
+    self.assertEqual('Unknown', R.propOr('Unknown', 3, deities))
+
+  def test_shows_the_same_behaviours_as_pathOr_for_a_nonexistent_property(self):
+    # TODO: implement pathOr
+    pass
+
+if __name__ == '__main__':
+  unittest.main()