How do you make the command mode case insensitive?

Question

For example, I might accidentally type something like :WQ and I want it to work like :wq when a hit enter

Another case is where I am typing a longer command name, for example NERDTreeTabsClose. (Note that I have the settings ignorecase and smartcase set)

1. I might start by typing :nerd and then hitting tab, which will auto complete to :NERDTree
2. I might then type a little more so that the command mode shows :NERDTreetab and then I hit tab again.
3. Because I have smart case on, the auto complete will not work. The ideal scenario would be for the auto complete to work

I would like to keep smartcase on, because that is useful for searches with /.

Is there a way to achieve the behaviour have described above

Answer 1

You can dynamically toggle smartcase using autocmds, so when in a : command line, it is off and when in a / command line it is on:

" assumes set ignorecase smartcase
augroup dynamic_smartcase
    autocmd!
    autocmd CmdLineEnter : set nosmartcase
    autocmd CmdLineLeave : set smartcase
augroup END

Answer 2

I've personally found https://github.com/thinca/vim-ambicmd to be fairly useful for long commands.