VIM: Quick autocompletion

This little VIM script enables autocompletion with the tab key. All words in the current file will be used as possible completions. No cross-file autocompletion yet. Put this into ~/.vimrc (or _vimrc in your VIM directory if you are on windows); create the file if it doesn’t exist:

" Autocompletion with <tab>
function InsertTabWrapper()
    let col = col('.') - 1
    if !col || getline('.')[col - 1] !~ '\k'
        return "\<tab>"
    else
        return "\<c-p>"
    endif
endfunction
inoremap <tab> <c-r>=InsertTabWrapper()