Question

I usually open code.h and code.cpp at the same time.
And display them side by side vertically in a window.

Currently I use:

$ vim -O code.{h,cpp}

If vim can run some commands(to manipulate filename) just before opening a file,
I can simply use:

$ vim code

How can I write this kind of vim-script?

---

Edit:

file_line.vim is great.

Answer 1

In this case, a possible solution is to modify the argument list (see :help
arglist) on Vim startup. It can be done using a VimEnter auto-command that
iterates over the argument list and replaces items not corresponding to
existing files with those items concatenated with certain suffixes, as
follows.

autocmd VimEnter * call AddArgsSuffixes(['.h', '.cpp'])
function! AddArgsSuffixes(sfx)
    let args = []
    for f in argv()
        if filereadable(f)
            call add(args, f)
        else
            for s in a:sfx
                call add(args, f . s)
            endfor
        endif
    endfor
    exe 'args' join(map(args, 'fnameescape(v:val)'))
endfunction