Here's what Guido v. R. says about Python: | Indentation | | Use the default of Emacs Python-mode: 4 spaces for one indentation | level. For really old code that you don't want to mess up, you can | continue to use 8-space tabs. Emacs Python-mode auto-detects the | prevailing indentation level used in a file and sets its indentation | parameters accordingly. | | Tabs or Spaces? | | Never mix tabs and spaces. The most popular way of indenting Python | is with spaces only. The second-most popular way is with tabs | only. Code indented with a mixture of tabs and spaces should be | converted to using spaces exclusively. (In Emacs, select the whole | buffer and hit ESC-x untabify.) When invoking the python command | line interpreter with the -t option, it issues warnings about code | that illegally mixes tabs and spaces. When using -tt these warnings | become errors. These options are highly recommended! (from http://www.python.org/doc/essays/styleguide.html) -kzm -- If I haven't seen further, it is by standing in the footprints of giants