how to freely format comments in cc-mode

Question

I'm quite new to cc-mode and I'd like to configure it to allow me to freely format and use tabs in multiline comments. This is important to me because I want to use cog.py in my source file and need to be able to format the python source in the comment correctly. I'd be ok with comments not beeing autoindented at all, however I'd like to keep auto indenting the rest of the source code.

Example:

...
/*
[[[cog
import cog
for x in ['a','b','c']:
>cog.outl(x)
]]]
*/
...

In the line marked with > I'd like to press TAB to indent the line. cc-mode simply does nothing at all if i do so. I could use spaces there (which is inconvenient) but every (semi-)automatic re-indentation of this block would cause the spaces to vanish and therefore the python code to be incorrectly indented (which is what happens if i happen to press tab somewhere on this line after indenting it with spaces).

I tried to start emacs without my .init to be sure this is default behavior and not modified by my configuration so far. I've done google searches and read the documentation of the cc-mode variables / functions I stumbled upon (cc-mode online docs) while searching for a solution (i.e. c-indent-comments-syntactically-p, c-indent-command, c-tab-always-indent,...) but none of these seemed to solve my question.

EDIT1: Thanks to abo-abo's idea of a "multi-major-mode" setup i've stumbled upon mmm-mode and have set up automatic switching to python mode for a cog section, which fixes most of my problems.

The only remaining problem is reindenting the whole file or a region containing a cog section. Can I somehow tell cc-mode to not change anything in comments while reindenting the file? mmm-mode + that would be a perfect solution for me.

Answer 1

You can use M-i to force a tab indent on the lines that you want, so you can use it to indent your comments.

You can also change your comments to use // instead. Just select your python code snippet, and do M-x comment-region:

// def foo(x):
//      print 'hi'

Then the autoindent won't mess up your indentation.