Bug#529087: vim: please implement a --drop-empty option

[Francesco Poli]

On Thu, 30 Jul 2009 16:00:57 +0200 James Vega wrote:

[...]
> On Sun, May 17, 2009 at 07:09:49PM +0200, Francesco Poli (t1000) wrote:
> > This option could be named "--drop-empty" or something like that.
> > It would work as follows: when vim (or view, or ...) is started with
> > this option, any newly created buffer
> 
> A buffer is created for every file you tell Vim to open, regardless of
> whether the file exists on disk yet or whether the file has any
> contents.

I am aware of this: my proposed option would indeed modify this
behavior, when it is useful to immediately close empty buffers...

> 
> > is checked and automatically closed if found to be empty.
> > 
> > This way, my use of View as a pager would automatically exit (with
> > 0 exit status, of course, because nothing went wrong) when the output
> > of some_command is empty:
> > 
> >   $ some_command | view --drop-empty -
> > 
> > [snip]
> > This could be useful when you want to edit already existing files,
> > without creating new ones, and you do *not* know in advance which
> > files exist (among the ones of a given list).
> 
> Vim notifies you that the buffer doesn't have a corresponding file on
> disk already.

What do you mean "Vim notifies me"?

When I issue the following command:

  $ some_command | view -

there *never* is a corresponding file for the newly opened buffer, IIUC.
When some_command writes something to its stdout, I can use View as a
pager to visualize this output.  On the other hand, when some_command
writes nothing to its stdout, View shows me the VIM "splash screen" and
I have to manually issue the :q command to exit.
I would like to have an option to automatically exit in the latter case.

> 
> > Could this new feature be implemented?
> > Please forward this feature request to upstream, if appropriate.
> 
> The feature is of marginal use and can be achieved through scripting.
> Tagging the bug as wontfix.

What's the best way to check whether the current buffer is empty in a
VIM script (that I can invoke with "view -s dropempty.vim")?

I searched in VIM documentation, but failed to find anything simpler
than

  $ cat dropempty.vim 
  :if line2byte(line("$") + 1) == 2
  :  q
  :endif

This script seems to work, but, frankly speaking, it's contorted,
inelegant, and needlessly complicated.
Moreover, it's a bit slow: I am able to see the "splash screen" shortly
flashing, before View exits.

Any better solutions?
 

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..................................................... Francesco Poli .
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