Re: How to do completion of toggle flag sequences separated by +/-

[Haakon Riiser <haakon.riiser@xxxxxxxxxx>]

On Sun, 1 May 2011 17:18:46 +0100, Peter Stephenson 
<p.w.stephenson@xxxxxxxxxxxx> wrote:
> On Sun, 01 May 2011 12:16:05 +0200
> Haakon Riiser <haakon.riiser@xxxxxxxxxx> wrote:
> >  I'm still working on perfecting the FFmpeg completion function, and 
> > one
> >  of the most important things missing is good completion of toggle 
> > flags.
> >
> >  Here's an example of FFmpeg's toggle flag syntax:
> >
> >  ffmpeg -flags +gmc-global_header+cgop
> > [...]
>
> I don't think there's a prepackaged way of doing this.  I've had some
> luck with the following.  One thing it doesn't do is treat the + and 
> -
> as separate from the options following, but a bit of patience might 
> sort
> that out.
>
> It's actually written to complete options for the fictitious "flags"
> command, so you also have to insinuate it into ffmpeg completion
> somehow.
> [...]

Thanks, that's an excellent starting point. I will try to integrate 
this into _ffmpeg shortly.

By the way: When defining sub-functions inside a completion function, 
is it recommended to test for their existence before defining them? 
E.g.,

(( $+functions[_ffmpeg_foo] )) || _ffmpeg_foo() {
  ...
}

I see this in a lot of completers included with zsh, and I assumed it 
was done for performance reasons (although it seems strange that the 
performance hit could be significant, considering that the code is only 
executed once per TAB keypress).

--
 Haakon