python tab completion Mac OSX 10.7 (Lion)

Question

Before upgrading to lion, I had tab complete working in a python shell via terminal. Following these instructions, it was possible to have tab complete working.

Sinc

Answer 1

Apple does not ship GNU readline with OS X. It does ship BSD libedit which includes a readline compatibility interface. The system Pythons shipped by Apple and the 64-bit/32-bit Pythons from python.org installers are built with libedit. The problem is that the commands supported by libedit are completely different from those of readline (see for example the discussion here). The traditional 32-bit-only python.org installers do use GNU readline as do some other 3rd-party distributors of Python for OS X, like MacPorts. Chances are that you were previously using such a Python and not a recent Apple one. You do have a few options, besides modifying Django: you can install the third-party replacement readline module; or you can use another Python that comes with GNU readline. However, you should not use the python.org 32-bit-only Pythons on 10.7 because, unfortunately, Xcode 4 on 10.7 no longer includes gcc-4.0 and the OS X 10.4u SDK which those Pythons need to build and install packages with C extension modules.

Putting the following in the python startup file will enable tab completion for both the libedit interface and the typical readline module. For more information on the python startup file, see here

import readline
import rlcompleter
if 'libedit' in readline.__doc__:
    readline.parse_and_bind("bind ^I rl_complete")
else:
    readline.parse_and_bind("tab: complete")