From da862ae23d4dac69833250ceabed029cf1917418 Mon Sep 17 00:00:00 2001
From: Ian Johnson <ian.johnson@appliedlanguage.com>
Date: Tue, 4 Jun 2013 17:29:01 +0100
Subject: Concurrent function components wait for futures in the executor
 thread pool.

---
 src/pypeline/helpers/parallel_helpers.py | 109 ++++++++++++++++---------------
 1 file changed, 58 insertions(+), 51 deletions(-)

diff --git a/src/pypeline/helpers/parallel_helpers.py b/src/pypeline/helpers/parallel_helpers.py
index 10af618..9084b1b 100644
--- a/src/pypeline/helpers/parallel_helpers.py
+++ b/src/pypeline/helpers/parallel_helpers.py
@@ -41,43 +41,45 @@ def cons_function_component(function,
                             output_forming_function = None,
                             state_mutator = None):
     """Construct a component based on a function. Any input or output forming functions shall be called if provided. A Kleisli arrow is returned."""
-    def bind_function(bind_a):
-        def state_function(wrapped_state):
-            # Unpack state
-            state = wrapped_state.state
-
-            # Handle input
-            if isinstance(bind_a, tuple):
-                the_a = (bind_a[0].result(), bind_a[1].result())
-            elif isinstance(bind_a, Future):
-                the_a = bind_a.result()
-            else:
-                the_a = bind_a
-
-            def do_transformation(a, s):
-                # Transform the input
-                transformed_a = input_forming_function(a, state) if input_forming_function else a
-
-                # Apply
-                new_a = function(transformed_a, state)
-
-                # Transform the output of the function
-                transformed_new_a = output_forming_function(new_a, state) if output_forming_function else new_a
-
-                return transformed_new_a
-
-            # Execute
-            new_future = wrapped_state.executor.submit(do_transformation,
-                                                       the_a,
-                                                       state)
-
-            # Mutate the state
-            next_state = state_mutator(state) if state_mutator else state
-            # New value/state pair
-            return (new_future, WrappedState(wrapped_state.executor, next_state))
-        return State(state_function)
-
-    return KleisliArrow(return_, bind_function)
+    def get_bind_function():
+        def bind_function(bind_a):
+            def state_function(wrapped_state):
+                # Unpack state
+                state = wrapped_state.state
+
+                def do_transformation(a, s):
+                    # Handle input
+                    if isinstance(a, tuple):
+                        the_a = (a[0].result(), a[1].result())
+                    elif isinstance(a, Future):
+                        the_a = a.result()
+                    else:
+                        the_a = a
+                    
+                    # Transform the input
+                    transformed_a = input_forming_function(the_a, state) if input_forming_function else the_a
+
+                    # Apply
+                    new_a = function(transformed_a, state)
+
+                    # Transform the output of the function
+                    transformed_new_a = output_forming_function(new_a, state) if output_forming_function else new_a
+
+                    return transformed_new_a
+
+                # Execute
+                new_future = wrapped_state.executor.submit(do_transformation,
+                                                           bind_a,
+                                                           state)
+
+                # Mutate the state
+                next_state = state_mutator(state) if state_mutator else state
+                # New value/state pair
+                return (new_future, WrappedState(wrapped_state.executor, next_state))
+            return State(state_function)
+        return bind_function
+
+    return KleisliArrow(return_, get_bind_function())
 
 
 def cons_wire(schema_conv_function):
@@ -113,22 +115,27 @@ def cons_dictionary_wire(conversions):
 
 def cons_split_wire():
     """Construct a wire that duplicates its input and produces a pair from this value. See: ***, first, second, and unsplit arrow operators."""
-    def split_func(a, s):
-        new_a = [None, None]
-        if isinstance(a, tuple):
-            for an_a, new_a_idx in zip(a, range(len(new_a))):
-                if isinstance(an_a, Future):
-                    new_a[new_a_idx] = an_a
+    def get_split_wire_bind_function():
+        def split_wire_bind_function(a):
+            def split_wire_state_function(s):
+                new_a = [None, None]
+                if isinstance(a, tuple):
+                    for an_a, new_a_idx in zip(a, range(len(new_a))):
+                        if isinstance(an_a, Future):
+                            new_a[new_a_idx] = an_a
+                        else:
+                            assert False, "Tuple does not contain futures: %s" % str(a)
                 else:
-                    assert False, "Tuple does not contain futures: %s" % str(a)
-        else:
-                new_a[0] = Future()
-                new_a[1] = Future()
-                new_a[0].set_result(a)
-                new_a[1].set_result(a)
+                    new_a[0] = Future()
+                    new_a[1] = Future()
+                    new_a[0].set_result(a)
+                    new_a[1].set_result(a)
+
+                return (tuple(new_a), s)
+            return State(split_wire_state_function)
+        return split_wire_bind_function
 
-        return tuple(new_a)
-    return cons_function_component(split_func)
+    return KleisliArrow(return_, get_split_wire_bind_function())
 
 
 def cons_unsplit_wire(unsplit_function):
-- 
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