Vim: mapping tab to ctrl space only if the cursor is in front of a non whitespace character

Question

I am using the jedi-vim extension and really don't like pressing ctrl-space to bring up auto-complete. I would like to use tab, but also obviously when coding I need tab for indentation as well.

I know that I will pretty much never press tab with the purpose of indenting when the character before my cursor is not a whitespace character. How can I map tab to ctrl space in this setting?

I only want it to apply in the case of a python file, and only in the current buffer (so if I change buffers the mapping disappears)

Answer 1

Actually looks like I figured something out. Other people porbably know better. But this seems to work for me:

" Map tab to ctrl space in python files when you have something other than
" whitespace
function NoAutoComplete()
    if getline(".")[col(".")-2] == " " || col(".") == 1
        return 1
    endif
endfunction 
autocmd FileType python imap <buffer> <expr> <Tab> NoAutoComplete() ? "\<TAB>" : "\<C-@>" 

Note: I believe the map must be recursive to properly map ctrl space to what jedi-vim uses. Furthermore I have these settings for my "normal tab" so that the function only needs to check for spaces:

" show existing tab with 4 spaces width
set tabstop=4

" when indenting with '>', use 4 spaces width
set shiftwidth=4

" On pressing tab, insert 4 spaces
set expandtab