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

[Haakon Riiser <haakon.riiser@fys.uio.no>]

 On Sun, 1 May 2011 17:18:46 +0100, Peter Stephenson 
 <p.w.stephenson@ntlworld.com> wrote:
> On Sun, 01 May 2011 12:16:05 +0200
> Haakon Riiser <haakon.riiser@fys.uio.no> 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