[FFmpeg-devel] [PATCH] doc/developer: update style guidelines to include for loops with declarations

[Aurelien Jacobs]

On Thu, Nov 09, 2017 at 04:56:07PM -0300, James Almer wrote:
> On 11/9/2017 2:46 PM, Clément Bœsch wrote:
> > On Wed, Nov 08, 2017 at 09:26:13PM +0000, Rostislav Pehlivanov wrote:
> >> Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
> >> ---
> >>  doc/developer.texi | 3 +++
> >>  1 file changed, 3 insertions(+)
> >>
> >> diff --git a/doc/developer.texi b/doc/developer.texi
> >> index a7b4f1d737..de7d887451 100644
> >> --- a/doc/developer.texi
> >> +++ b/doc/developer.texi
> >> @@ -132,6 +132,9 @@ designated struct initializers (@samp{struct s x = @{ .i = 17 @};});
> >>  @item
> >>  compound literals (@samp{x = (struct s) @{ 17, 23 @};}).
> >>  
> >> + at item
> >> +for loops with variable definition (@samp{for (int i = 0; i < 8; i++)});
> >> +
> > 
> > I'm fine with this and would be happy to update all the code I maintain in
> > FFmpeg to follow this pattern. But I have a few questions/reservations:
> > 
> > - what does it imply for mixed statements and declarations?

Nothing at all. It is unrelated to mixed statements and declarations.

> >   If we still do not allow them, how are you going to make the compiler
> >   reject them but not the for (int ... ) form?

By not changing anything at all. That is already what happens right now.

> No way to do that i guess. If we remove the warning, it will never catch
> any kind of mixed declarations and statements anymore.

No need to remove any warning. The -Wdeclaration-after-statement does
not emit warnings regarding for loops with declarations.

> >   Also, allowing this but not the mixed statements and declarations means
> >   this is a style decision and not a technical one anymore.

Allowing limiting the scope of a variable to a loop seems like a
technical decision to me, but I understand that some consider it more
of a style decision.

> > [...]
> > 
> > Overall, I'd enjoy this change being accepted (even along mixed statements
> > and declarations).

Just for the record, I would enjoy it as well.