Implement uncurry

toolz/functoolz.py

@@ -821,6 +821,36 @@ def __name__(self):
         except AttributeError:
             return 'excepting'
 
+@curry
+def uncurry(func, arg):
+    """ Call the function unpacking the argument tuple / dict provided.
+
+    This function is curried.
+
+    >>> def f(a, b, c):
+    ...     return a + b + c
+    ...
+    >>> f(1, 2, 3)
+    6
+    >>> f(1, 2, 3) == uncurry(f, (1, 2, 3))
+    True
+    >>> def g(foo, bar):
+    ...     return foo + bar
+    ...
+    >>> g(1, 2)
+    3
+    >>> g(1, 2) == uncurry(g, {'foo': 1, 'bar': 2})
+    True
+    """
+    if (
+        hasattr(arg, 'keys')
+        and callable(arg.keys)
+        and hasattr(arg, '__getitem__')
+        and callable(arg.__getitem__)
+    ):
+        return func(**arg)
+    else:
+        return func(*arg)
 
 def _check_sigspec(sigspec, func, builtin_func, *builtin_args):
     if sigspec is None:

toolz/tests/test_functoolz.py

@@ -1,8 +1,8 @@
 import inspect
 import toolz
 from toolz.functoolz import (thread_first, thread_last, memoize, curry,
-                             compose, compose_left, pipe, complement, do, juxt,
-                             flip, excepts, apply)
+    compose, compose_left, pipe, complement, do, juxt,
+    flip, excepts, apply, uncurry)
 from operator import add, mul, itemgetter
 from toolz.utils import raises
 from functools import partial
@@ -797,3 +797,20 @@ def raise_(a):
     excepting = excepts(object(), object(), object())
     assert excepting.__name__ == 'excepting'
     assert excepting.__doc__ == excepts.__doc__
+
+
+def test_uncurry():
+    assert uncurry(lambda x, y: 2 * x + y)((2, 1)) == 5
+    assert uncurry(lambda foo, bar: 2 * foo + bar)({'foo': 2, 'bar': 1}) == 5
+
+    def test_args(*args):
+        if len(args) == 0:
+            return 0
+        else:
+            return args[-1] + 2 * test_args(*args[:-1])
+    assert uncurry(test_args)((3, 2, 1)) == 17
+
+    def test_kwargs(**kwargs):
+        return ", ".join(f"{k}={v}" for k, v in kwargs.items())
+
+    assert uncurry(test_kwargs)({"a": 1, "b": 2, "c": 3}) == "a=1, b=2, c=3"