add method ap

README.md

@@ -75,7 +75,7 @@ R.add(date(1,2,3), date(1,2,3)) # float('nan)
 - [ ] andThen
 - [x] 0.1.2 any
 - [ ] anyPass
-- [ ] ap
+- [x] ap
 - [ ] aperture
 - [x] 0.1.2 append
 - [ ] apply

ramda/__init__.py

@@ -5,6 +5,7 @@
 from .always import always
 from .And import And
 from .any import any
+from .ap import ap
 from .append import append
 from .binary import binary
 from .clone import clone

ramda/ap.py

@@ -0,0 +1,19 @@
+from .map import map
+from .private._concat import _concat
+from .private._curry2 import _curry2
+from .private._helper import getAttribute
+from .private._isFunction import _isFunction
+from .private._reduce import _reduce
+
+
+def inner_ap(applyF, applyX):
+  if _isFunction(getAttribute(applyX, 'fantasy-land/ap')):
+    return getAttribute(applyX, 'fantasy-land/ap')(applyF)
+  if _isFunction(getAttribute(applyF, 'ap')):
+    return getAttribute(applyF, 'ap')(applyX)
+  if _isFunction(applyF):
+    return lambda x: applyF(x)(applyX(x))
+  return _reduce(lambda acc, f: _concat(acc, map(f, applyX)), [], applyF)
+
+
+ap = _curry2(inner_ap)

test/helpers/Id.py

@@ -0,0 +1,19 @@
+import ramda as R
+from ramda.private._helper import getAttribute
+
+
+def Id(value):
+  return {
+      '@@type': 'ramda/Id',
+      'fantasy-land/equals': lambda other: other is not None and getAttribute(other, '@@type') == 'ramda/Id' and R.equals(getAttribute(other, 'value'), value),
+      'fantasy-land/concat': lambda id: Id(R.concat(value, getAttribute(id, 'value'))),
+      'fantasy-land/map': lambda f: Id(f(value)),
+      'fantasy-land/ap': lambda id: Id(getAttribute(id, 'value')(value)),
+      'fantasy-land/chain': lambda f: f(value),
+      'fantasy-land/reduce': lambda f, x: f(x, value),
+      'fantasy-land/traverse': lambda f, of: R.map(Id, f(value)),
+      'sequence': lambda of: R.map(Id, value),
+      'constructor': {'fantasy-land/of': Id},
+      'toString': lambda: 'Id(' + R.toString(value) + ')',
+      'value': value
+  }

test/test_ap.py

@@ -1,25 +1,40 @@
 
 import unittest
+from test.helpers.Id import Id
 
 import ramda as R
 
 """
 https://github.com/ramda/ramda/blob/master/test/ap.js
 """
 
+mult2 = R.multiply(2)
+plus3 = R.add(3)
+
 
 class TestAp(unittest.TestCase):
-  def test_returns_an_array_of_tuples(self):
-    a = [1, 2, 3]
-    b = [100, 200, 300]
-    self.assertEqual([[1, 100], [2, 200], [3, 300]], R.zip(a, b))
-
-  def test_returns_a_list_as_long_as_the_shorter_of_the_lists_input(self):
-    a = [1, 2, 3]
-    b = [100, 200, 300, 400]
-    c = [10, 20]
-    self.assertEqual([[1, 100], [2, 200], [3, 300]], R.zip(a, b))
-    self.assertEqual([[1, 10], [2, 20]], R.zip(a, c))
+  def test_interprets_list_a_as_an_applicative(self):
+    self.assertEqual([2, 4, 6, 4, 5, 6], R.ap([mult2, plus3])([1, 2, 3]))
+
+  def test_interprets_arrow_r_as_an_applicative(self):
+    def f(r): return lambda a: r + a
+    def g(r): return r * 2
+    h = R.ap(f, g)
+    # (<*>) :: (r -> a -> b) -> (r -> a) -> r -> b
+    # f <*> g = \x -> f x (g x)
+    self.assertEqual(10 + (10 * 2), h(10))
+    self.assertEqual(10 + (10 * 2), R.ap(R.add)(g)(10))
+
+  def test_dispatches_to_the_first_passed_object_ap_method_when_values_is_a_non_array(self):
+    obj = {'ap': lambda n: 'called ap with ' + str(n)}
+    self.assertEqual(obj['ap'](10), R.ap(obj, 10))
+
+  def test_works_with_fantasy_land_ap(self):
+    applyX = Id(10)
+    applyF = {'value': lambda x: x * 2}
+    res = R.ap(applyF, applyX)
+    self.assertEqual(20, res['value'])
+    self.assertEqual('ramda/Id', res['@@type'])
 
 if __name__ == '__main__':
   unittest.main()