code folding with <backtab> ?

[Yagnesh Raghava Yakkala]

Hello all,

Just like org does, folding (or cycling) with its outlines by pressing
backtab(shift+<tab>), I would want every programming language buffer to show
such a /outline/ of the program(buffer) to get a overview of the program I am
working on. I know this depends on the major mode of the current buffer and
combination of suitable minor modes namely outline-minor-mode or
hs-minor-mode. (or may be with CEDET with its semantic parsing)


To begin with elisp, can anybody tell me how to make backtab to show the
outline of the buffer at least for two levels. I mean first press would show
me buffer folded upto top level comments, defuns, defcustoms and defvars
and the second press would show me entire buffer.


I hope my question is clear.

Thanks. 
--
YYR