From ecfeb0019c1085c58ddd77a833f7a75df8628c23 Mon Sep 17 00:00:00 2001
From: Crista Lopes <crista@tagide.com>
Date: Thu, 17 Oct 2013 20:30:30 -0700
Subject: [PATCH] Better version of reactive style. Added README.md

---
 32-reactive/README.md | 13 ++++++++++
 32-reactive/tf-32.py  | 55 ++++++++++++++++++++++++++++---------------
 2 files changed, 49 insertions(+), 19 deletions(-)
 create mode 100644 32-reactive/README.md

diff --git a/32-reactive/README.md b/32-reactive/README.md
new file mode 100644
index 0000000..12321c8
--- /dev/null
+++ b/32-reactive/README.md
@@ -0,0 +1,13 @@
+Style #32
+==============================
+
+Constraints:
+
+- Variables are updated automatically based on changing values of
+  other variables. Variable values possibly depend on data streams
+  (keyboard, mouse, etc.)
+
+Possible names:
+
+- Reactive
+- Data-to-data
diff --git a/32-reactive/tf-32.py b/32-reactive/tf-32.py
index bc9d272..8cdd9a3 100644
--- a/32-reactive/tf-32.py
+++ b/32-reactive/tf-32.py
@@ -1,21 +1,44 @@
 #!/usr/bin/env python
 
-import sys, operator, string, os
+import sys, operator, string, os, threading
 from util import getch, cls
 from time import sleep
 
-def refresh_screen(data):
-    # clear screen
-    cls()
-    print data
-    sys.stdout.flush()
+#
+# The reactive infrastructure
+#
+class FreqObserver(threading.Thread):
+    def __init__(self, freqs):
+        threading.Thread.__init__(self)
+        self.daemon = True
+        # freqs is the data to be observed and reacted to
+        self._freqs = freqs
+        self._freqs_0 = sorted(self._freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        self.start()
 
-def update_display(tuples):
-    data_str = ""
-    for tf in tuples:
-        data_str += str(tf[0]) + ' - ' + str(tf[1]) + '\n'
-    refresh_screen(data_str)
+    def run(self):
+        while True:
+            freqs_1 = sorted(self._freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+            if (freqs_1[0:25] != self._freqs_0[0:25]):
+                self._update_display(freqs_1[0:25])
+            self._freqs_0 = freqs_1
+            sleep(0.01)
 
+    def _update_display(self, tuples):
+        def refresh_screen(data):
+            # clear screen
+            cls()
+            print data
+            sys.stdout.flush()
+
+        data_str = ""
+        for tf in tuples:
+            data_str += str(tf[0]) + ' - ' + str(tf[1]) + '\n'
+        refresh_screen(data_str)
+
+#
+# The active part, dataflow-like
+#
 automatic = False
 def get_input():
     global automatic
@@ -72,25 +95,19 @@ def non_stop_words(filename):
             yield w
 
 def count_and_sort(filename):
-    freqs_0 = ()
-    freqs_1 = ()
     freqs = {}
+    # The declaration for reactive observation of freqs
+    FreqObserver(freqs)
     while get_input():
         try:
             w = non_stop_words(filename).next()
             freqs[w] = 1 if w not in freqs else freqs[w]+1
-            freqs_0 = freqs_1
-            freqs_1 = sorted(freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
-            if (freqs_1[0:25] != freqs_0[0:25]):
-                update_display(freqs_1[0:25])
         except StopIteration:
             break
-    return freqs_1
 
 #
 # The main function
 #
-
 print "Press space bar to fetch words from the file one by one"
 print "Press ESC to switch to automatic mode"
 count_and_sort(sys.argv[1])