@amitu

If you were curios about the "# {{{" and "# }}}" in my previous post about extending django user model, they are code folding markers. Getting code folding right in vim took me some time and learning, so here I am documenting the takeaways. Code folding, hiding parts of code that you are not working on, is really cool and helpful, and once you start using it, you can not live without it. Here is how to do it in vim.

Pick The Fold Method 

First of all, you have to decide the method for code folding. Vim offers many methods. First is manual, which is basic, you can fold any piece of text at your whim. This might be good for one off or free form texts. Then comes markers. This is my preferred approach for folding as it can be fairly arbitrary, and it can be preserved in version control and gets shared with multiple developers. Then there is folding by indentation, and language syntax. Both these will let you quickly fold things if you have not manually handpicked folding markers. 

Learn The Keys 

Once the method has been decided, then comes the commands, here is a short list:

• zf create the fold, useful for manual and marker methods. Select any piece of text, [press v or shift-v, then use arrow keys], and then press zf. It will place the markers around the fold for you in marker mode; in case of manual, it will store fold location in memory. Remember f by saying this command "forms" the fold, or just remember fold :-)
• zc close the fold at the cursor.
  
• zo open the fold at the cursor.
• zr  increment the fold level by one, so if all classes are folded, they will opened, but function definitions will be kept folded.
  
• zm reverse of the above, if one or more function folds are open, they will be closed, but classes will be kept open.
  
• zR open all folds.
• zM close all folds.
• zj and zk can be used to jump from one fold to another. 

Thats it, that is all you need to know about folding in vim, all commands start with z so they are easy to remember. Z represents a piece of folded paper. From my experience you will be only using zf, zo, zc, zj and zk, and these key combinations have been selected quite wisely to make it easy to remember. 

Configure Things

Here is my complete vimrc file, optimized for python source editing:

" enter spaces when tab is pressed:
set expandtab
" do not break lines when line lenght increases
set textwidth=0
" user 4 spaces to represent a tab
set tabstop=4
set softtabstop=4
" number of space to use for auto indent
" you can use >> or << keys to indent current line or selection
" in normal mode.
set shiftwidth=4
" Copy indent from current line when starting a new line.
set autoindent
" makes backspace key more powerful.
set backspace=indent,eol,start
" shows the match while typing
set incsearch
" case insensitive search
set ignorecase
" show line and column number
set ruler
" show some autocomplete options in status bar
set wildmenu

" automatically save and restore folds
au BufWinLeave * mkview
au BufWinEnter * silent loadview

" this lets us put the marker in the file so that
" it can be shared across and stored in version control.
set foldmethod=marker
" this is for python, put
" # name for the folded text # {{{
" to begin marker and
" # }}}
" close to end it.
set commentstring=\ #\ %s
" default fold level, all open, set it 200 or something
" to make it all closed.
set foldlevel=0

" share clipboard with windows clipboard
set clipboard+=unnamed

" set viminfo='100,f1
" minibufexplorer settings:j
let g:miniBufExplMapWindowNavArrows = 1
let g:miniBufExplMapCTabSwitchWindows = 1

syntax on

Enjoy!