Fix bug with 2.3 and readline; clean up.

IPython/rlineimpl.py

@@ -1,54 +1,40
 # -*- coding: utf-8 -*-
-""" Imports and provides the "correct" version of readline for the platform.
+""" Imports and provides the 'correct' version of readline for the platform.
 
-Readline is used throughout IPython as "import IPython.rlineimpl as readline.
+Readline is used throughout IPython as 'import IPython.rlineimpl as readline'.
 
-In addition to normal readline stuff, this module provides have_readline boolean 
-and _outputfile variable used in genutils.
+In addition to normal readline stuff, this module provides have_readline
+boolean and _outputfile variable used in genutils.
 
 $Id: Magic.py 1096 2006-01-28 20:08:02Z vivainio $"""
 
-
 import sys
 
-have_readline = False
-
-if sys.platform == 'win32':
-    try:
-        import pyreadline.rlmain
-        #add config for inputrcpath here:
-        #pyreadline.rlmain.config_path="c:/python/test_config.ini"
-        from readline import *
-        #print "Using the new pyreadline (thanks for participating in the testing!)"
-        
-        have_readline = True
-        
-        import readline as _rl
-    except ImportError:
-        #print "IPython team recommends the new pyreadline for Windows use, "
-        #print "It's superior especially with non-US keyboard layouts."
-        #print "Try installing it with 'easy_install pyreadline (ctypes is required) or"
-        #print "svn co http://ipython.scipy.org/svn/ipython/pyreadline/trunk pyreadline"
-        #print "Trying 'old' windows readline."
-        #print "Using 'old' readline, you might want to try pyreadline:"
-        #print "http://projects.scipy.org/ipython/ipython/wiki/PyReadline/Intro"
         try:
             from readline import *
             import readline as _rl
             have_readline = True
         except ImportError:
-            pass
+    have_readline = False
 
-    if have_readline:
+if sys.platform == 'win32' and have_readline:
         try:
             _outputfile=_rl.GetOutputFile()
         except NameError:
             print "Failed GetOutputFile"
             have_readline = False
     
-else:
+# the clear_history() function was only introduced in Python 2.4 and is
+# actually optional in the readline API, so we must explicitly check for its
+# existence.  Some known platforms actually don't have it.  This thread:
+# http://mail.python.org/pipermail/python-dev/2003-August/037845.html
+# has the original discussion.
+
+if have_readline:
+    import readline
     try:
-        from readline import *
-        have_readline = True
-    except ImportError:
-        pass
+        readline.clear_history
+    except AttributeError:
+        def clear_history(): pass
+        readline.clear_history = clear_history
+    del readline

doc/ChangeLog

@@ -1,5 +1,10
 2007-05-10  Fernando Perez  <[e-mail]>
 
+	* IPython/rlineimpl.py: check for clear_history in readline and
+	make it a dummy no-op if not available.  This function isn't
+	guaranteed to be in the API and appeared in Python 2.4, so we need
+	to check it ourselves.  Also, clean up this file quite a bit.
+
 	* ipython.1: update man page and full manual with information
 	about threads (remove outdated warning).  Closes #151.