In VIM how to make NERDTree open at startup nicely when giving args -

let me explain question, want is:

1. from command line calling gvim without arguments, want nerdtree open default in /home/user/documents folder.

2. from command line calling gvim . want open nerdtree directory set actual directory command executed from. still want nerdtree on left , empty buffer in right (not nerdtree being window happens).

3. from command line calling gvim /some/path/to/folder want open nerdtree directory set given directory. still want nerdtree on left , empty buffer in right (not nerdtree being window happens).

4. when calling gvim argument:

   • if file, don't open nerdtree file.
   • if directory nerdtree should work #3

to address #1 have:

function! startup()     if 0 == argc()         nerdtree ~/documents     endif endfunction  autocmd vimenter * call startup() autocmd vimenter * wincmd p 

what thinking address #2 , #3 was:

function! startup()     if 0 == argc()         nerdtree ~/documents     else         if argv(0) == '.'             nerdtree expand(getcwd())         else             nerdtree expand(argv(0))         endif     endif endfunction  autocmd vimenter * call startup() autocmd vimenter * wincmd p 

but doesn't work, gives me errors , vim freezes times. can achieve desired effect?

thanks help.

complete solution

does not work expected it's very close. far god.

function! startup()     if 0 == argc()         nerdtree ~/documents     else         if argv(0) == '.'             execute 'nerdtree' getcwd()         else             execute 'nerdtree' getcwd() . '/' . argv(0)         endif     endif endfunction  autocmd vimenter * call startup() autocmd vimenter * wincmd p 

i can't give complete solution, here's hint should resolve errors:

the :nerdtree command takes (optional) directory; doesn't resolve expressions. vim's evaluation rules different programming languages. need use :execute in order evaluate variable (or expression); otherwise, it's taken literally; i.e. vim uses variable name argument. change this:

nerdtree expand(getcwd()) 

into:

execute 'nerdtree' getcwd() 

i've left out expand(), getcwd() returns full path.