# HG changeset patch
# User paulb
# Date 1189885269 0
# Node ID 650cd5af09a5d2386d606cbff5c62cde6c8c50f3
# Parent  4044f325e3e7074be5e43b5df43b8cdc248a1232
[project @ 2007-09-15 19:41:09 by paulb]
Made the Map class more usable as a result collector with the usual
Exchange methods and managed callables, rather than being called itself and
directly providing a result. Added iterator and list-style access through
Map objects, rather than returning the results list to a caller.

diff -r 4044f325e3e7 -r 650cd5af09a5 pprocess.py
--- a/pprocess.py	Sat Sep 15 15:57:34 2007 +0000
+++ b/pprocess.py	Sat Sep 15 19:41:09 2007 +0000
@@ -578,6 +578,18 @@
 
     "An exchange which can be used like the built-in 'map' function."
 
+    def __init__(self, *args, **kw):
+        Exchange.__init__(self, *args, **kw)
+        self.init()
+
+    def init(self):
+
+        "Remember the channel addition order to order output."
+
+        self.channel_number = 0
+        self.channels = {}
+        self.results = []
+
     def add(self, channel):
 
         "Add the given 'channel' to the exchange."
@@ -586,6 +598,17 @@
         self.channels[channel] = self.channel_number
         self.channel_number += 1
 
+    def start(self, callable, *args, **kw):
+
+        """
+        Using pprocess.start, create a new process for the given 'callable'
+        using any additional arguments provided. Then, monitor the channel
+        created between this process and the created process.
+        """
+
+        self.results.append(None) # placeholder
+        Exchange.start(self, callable, *args, **kw)
+
     def __call__(self, callable, sequence):
 
         "Wrap and invoke 'callable' for each element in the 'sequence'."
@@ -595,21 +618,24 @@
         else:
             wrapped = callable
 
-        # Remember the channel addition order to order output.
+        self.init()
 
-        self.channel_number = 0
-        self.channels = {}
-        self.results = []
+        # Start processes for each element in the sequence.
 
         for i in sequence:
-            self.results.append(None) # placeholder
             self.start(wrapped, i)
-        self.finish()
+
+        # Access to the results occurs through this object.
+
+        return self
 
-        # NOTE: Could return results as they arrive, but we would then need to
-        # NOTE: return the position of each result in the original sequence.
+    def __getitem__(self, i):
+        self.finish()
+        return self.results[i]
 
-        return self.results
+    def __iter__(self):
+        self.finish()
+        return iter(self.results)
 
     def store_data(self, channel):