Finish compose.py.

resources/python/compose.py

@@ -1,30 +1,57 @@
+import collections
 import functools
 
-
-def compose2(f, g):
-    return lambda x: f(g(x))
+from partialable import n_partialable
 
 
-def compose(*functions):
-    return reduce(compose2, functions)
+def _compose2(f, g):
+    return lambda *args, **kwargs: f(g(*args, **kwargs))
 
 
-def extract_args(function):
+@n_partialable(evaluation_checker=n_partialable.count_evaluation_checker(2))
+def compose_with_joiner(joiner, *functions):
+    return reduce(joiner, functions)
+
+
+compose_one_arg = compose_with_joiner(_compose2)
+
+
+compose = compose_with_joiner(lambda f, g: _compose2(make_single_arity(f),
+                                                force_args_return(g)))
+
+
+def make_single_arity(function):
     @functools.wraps(function)
     def wrapped(args):
         return function(*args)
     return wrapped
 
 
-def extract_kwargs(function):
+def kwargs_make_single_arity(function):
     @functools.wraps(function)
     def wrapped(kwargs):
         return function(**kwargs)
     return wrapped
 
 
-def extract_args_kwargs(function):
+def args_kwargs_make_single_arity(function):
     @functools.wraps(function)
     def wrapped((args, kwargs)):
         return function(*args, **kwargs)
     return wrapped
+
+
+def force_args_return(function):
+    @functools.wraps(function)
+    def wrapped(*args, **kwargs):
+        value = function(*args, **kwargs)
+        if not isinstance(value, collections.Iterable):
+            value = (value,)
+        return value
+    return wrapped
+
+
+def tee(*functions):
+    def wrapped(*args, **kwargs):
+        return tuple(function(*args, **kwargs) for function in functions)
+    return wrapped