Changeset 354

Timestamp:

06/21/08 23:00:10 (4 years ago)

Author:

simon

Message:

Clean up talk utilities.

Files:

• hodgestar/Talks/PythonObjects/util.py (modified) (6 diffs)

hodgestar/Talks/PythonObjects/util.py

@@ +1 @@
+"""Utility module for use with pyobjects talk."""
+
 import gc
 import random
@@ -6 +8 @@
 import sys
 
-os.chdir('/home/simon/LocalProjects/PythonSpint/trunk')
+#
+# Old vs New Classes and Slots
+#
 
 class Old:
+    """A classic or old-style class."""
     pass
 
 class New(object):
+    """A new-style class with a useful type."""
     pass
 
 class FuBar(object):
+    """Illustrates the difference between __str__ and
+       __unicode__. __str__ has a slot (tp_str) while
+       __unicode__ does not.
+       """
     def __str__(self):
         return "fubar"
@@ -21 +31 @@
 
 class OldFu:
+    """Like FuBar, but showing it with classic classes."""
     def __str__(self):
         return "fubar"
@@ -26 +37 @@
         return unicode("fubar")
 
+#
+# Grabbing the interned string dictionary
+# and a simple Python keyword game
+#
+
+PYTHON_TRUNK_CHECKOUT = '/home/simon/LocalProjects/PythonSpint/trunk'
+
 def find_big_dict(x):
+    """Use gc to find the first dict with len greater than 1000
+       that references x.
+       """
     for obj in gc.get_referrers(x):
         if type(obj) is dict and len(obj) > 1000:
@@ -33 +54 @@
 
 def find_str_interns():
+    """Find interned string dict by looking for a big dict that
+       refers to "a".
+       """
     return find_big_dict("a")
 
 def keyword_quiz():
+    """Looks up upper case keywords in the interned string dict
+       and asks users to guess which part of Python they come
+       from. Prints answers by grepping Python source.
+       """
     interned = find_big_dict("a")
     keywords = [x for x in interned if x.isupper() and len(x) > 4]
     question = random.choice(keywords)
 
-    egrep = subprocess.Popen(["egrep", "-R", "-l", "--exclude-dir", ".svn",
+    pwd = os.getcwd()
+    try:
+        os.chdir(PYTHON_TRUNK_CHECKOUT)
+        egrep = subprocess.Popen(["egrep", "-R", "-l", "--exclude-dir", ".svn",
                               "--include", "*.c", "--include", "*.h", "--include", "*.py",
                               '%s' % question,
                               "Modules", "Lib"], stdout=subprocess.PIPE)
-    answer, err = egrep.communicate()
+        answer, err = egrep.communicate()
+    finally:
+        os.chdir(pwd)
 
     print ("Which module does the keyword " + question + " appear in?")
@@ -55 +88 @@
     print (answer)
 
-# From:
-# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/286222
-#
+# Recipe for measuring process memory usage, taken from
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/286222.
+# According to http://aspn.activestate.com/ASPN/Python/Cookbook/
+# licensed under the Python license unless otherwise stated.
+# I'm taking this to mean Python license 2.1 or newer which is
+# GPL compatible.
 
 _proc_status = '/proc/' + str(os.getpid()) + '/status'