Query on CodingStyle: indentation

Query on CodingStyle: indentation

[Kumar amit mehta]

Hi,

I've a query regarding the coding style for Linux Kernel code. I'm
reading the CodingStyle under Documentation and what I've understood is
that I shouldn't be using spaces for indentation purposes and should use
tabs of width 8 characters. Quoting from the same document: 
"Outside of comments, documentation and except in Kconfig, spaces are
never used for indentation, and the above example is deliberately broken."
However, Is it correct to replace each tab stroke by 8 spaces ? I use vim
editor and I've put following under $HOME/.vimrc file:
<snip>
set tabstop=8
set shiftwidth=8 
set expandtab
<snip>

In past I've seen that some application have different interpretation of
tabs and hence sometimes even If I've done proper indentation using tab,
the code appears unindented, and therefore In order to make sure that I'm
moving 8 characters upon hitting tab, I've put the above rules under my
.vimrc file. Please let me know If I should remove these from my .vimrc
file and rely on tab instead.

-Amit

Query on CodingStyle: indentation

[Adam Lee]

On Thu, Oct 18, 2012 at 10:31:29PM -0700, Kumar amit mehta wrote:
> Hi,
> 
> I've a query regarding the coding style for Linux Kernel code. I'm
> reading the CodingStyle under Documentation and what I've understood is
> that I shouldn't be using spaces for indentation purposes and should use
> tabs of width 8 characters. Quoting from the same document: 
> "Outside of comments, documentation and except in Kconfig, spaces are
> never used for indentation, and the above example is deliberately broken."
> However, Is it correct to replace each tab stroke by 8 spaces ? I use vim
> editor and I've put following under $HOME/.vimrc file:
> <snip>
> set tabstop=8
> set shiftwidth=8 
> set expandtab
> <snip>
> 
> In past I've seen that some application have different interpretation of
> tabs and hence sometimes even If I've done proper indentation using tab,
> the code appears unindented, and therefore In order to make sure that I'm
> moving 8 characters upon hitting tab, I've put the above rules under my
> .vimrc file. Please let me know If I should remove these from my .vimrc
> file and rely on tab instead.

No, you should not expand tabs. Tabs in CodingStyle mean _hard_ tabs.

Mine:

<snip>
set tabstop=8
set noexpandtab
set shiftwidth=8
set cinoptions=:0,l1,t0,g0
<snip>

-- 
Regards,
Adam Lee
http://adam8157.info

Query on CodingStyle: indentation

[Kumar amit mehta]

On Fri, Oct 19, 2012 at 03:03:28PM +0800, Adam Lee wrote:
> On Thu, Oct 18, 2012 at 10:31:29PM -0700, Kumar amit mehta wrote:
> > Hi,
> > 
> > I've a query regarding the coding style for Linux Kernel code. I'm
> > reading the CodingStyle under Documentation and what I've understood is
> > that I shouldn't be using spaces for indentation purposes and should use
> > tabs of width 8 characters. Quoting from the same document: 
> > "Outside of comments, documentation and except in Kconfig, spaces are
> > never used for indentation, and the above example is deliberately broken."
> > However, Is it correct to replace each tab stroke by 8 spaces ? I use vim
> > editor and I've put following under $HOME/.vimrc file:
> > <snip>
> > set tabstop=8
> > set shiftwidth=8 
> > set expandtab
> > <snip>
> > 
> > In past I've seen that some application have different interpretation of
> > tabs and hence sometimes even If I've done proper indentation using tab,
> > the code appears unindented, and therefore In order to make sure that I'm
> > moving 8 characters upon hitting tab, I've put the above rules under my
> > .vimrc file. Please let me know If I should remove these from my .vimrc
> > file and rely on tab instead.
> 
> No, you should not expand tabs. Tabs in CodingStyle mean _hard_ tabs.
> 
> Mine:
> 
> <snip>
> set tabstop=8
> set noexpandtab
> set shiftwidth=8
> set cinoptions=:0,l1,t0,g0
> <snip>
>

Thank you Adam for sharing your vim recipe.

Query on CodingStyle: indentation

[Greg Freemyer]

On Fri, Oct 19, 2012 at 5:00 AM, Kumar amit mehta <gmate.amit@gmail.com> wrote:
> On Fri, Oct 19, 2012 at 03:03:28PM +0800, Adam Lee wrote:
>> On Thu, Oct 18, 2012 at 10:31:29PM -0700, Kumar amit mehta wrote:
>> > Hi,
>> >
>> > I've a query regarding the coding style for Linux Kernel code. I'm
>> > reading the CodingStyle under Documentation and what I've understood is
>> > that I shouldn't be using spaces for indentation purposes and should use
>> > tabs of width 8 characters. Quoting from the same document:
>> > "Outside of comments, documentation and except in Kconfig, spaces are
>> > never used for indentation, and the above example is deliberately broken."
>> > However, Is it correct to replace each tab stroke by 8 spaces ? I use vim
>> > editor and I've put following under $HOME/.vimrc file:
>> > <snip>
>> > set tabstop=8
>> > set shiftwidth=8
>> > set expandtab
>> > <snip>
>> >
>> > In past I've seen that some application have different interpretation of
>> > tabs and hence sometimes even If I've done proper indentation using tab,
>> > the code appears unindented, and therefore In order to make sure that I'm
>> > moving 8 characters upon hitting tab, I've put the above rules under my
>> > .vimrc file. Please let me know If I should remove these from my .vimrc
>> > file and rely on tab instead.
>>
>> No, you should not expand tabs. Tabs in CodingStyle mean _hard_ tabs.
>>
>> Mine:
>>
>> <snip>
>> set tabstop=8
>> set noexpandtab
>> set shiftwidth=8
>> set cinoptions=:0,l1,t0,g0
>> <snip>
>>
>
> Thank you Adam for sharing your vim recipe.

I believe you can still use your standard vim recipe, then run
checkpatch.pl on your patches to replace spaces with tabs before
sending them to upstream.

Someone else who uses that workflow would need to confirm that works well.

Greg

Query on CodingStyle: indentation

[Kumar amit mehta]

On Fri, Oct 19, 2012 at 11:40:35AM -0400, Greg Freemyer wrote:
> On Fri, Oct 19, 2012 at 5:00 AM, Kumar amit mehta <gmate.amit@gmail.com> wrote:
> > On Fri, Oct 19, 2012 at 03:03:28PM +0800, Adam Lee wrote:
> >> On Thu, Oct 18, 2012 at 10:31:29PM -0700, Kumar amit mehta wrote:
> >> > Hi,
> >> >
> >> > I've a query regarding the coding style for Linux Kernel code. I'm
> >> > reading the CodingStyle under Documentation and what I've understood is
> >> > that I shouldn't be using spaces for indentation purposes and should use
> >> > tabs of width 8 characters. Quoting from the same document:
> >> > "Outside of comments, documentation and except in Kconfig, spaces are
> >> > never used for indentation, and the above example is deliberately broken."
> >> > However, Is it correct to replace each tab stroke by 8 spaces ? I use vim
> >> > editor and I've put following under $HOME/.vimrc file:
> >> > <snip>
> >> > set tabstop=8
> >> > set shiftwidth=8
> >> > set expandtab
> >> > <snip>
> >> >
> >> > In past I've seen that some application have different interpretation of
> >> > tabs and hence sometimes even If I've done proper indentation using tab,
> >> > the code appears unindented, and therefore In order to make sure that I'm
> >> > moving 8 characters upon hitting tab, I've put the above rules under my
> >> > .vimrc file. Please let me know If I should remove these from my .vimrc
> >> > file and rely on tab instead.
> >>
> >> No, you should not expand tabs. Tabs in CodingStyle mean _hard_ tabs.
> >>
> >> Mine:
> >>
> >> <snip>
> >> set tabstop=8
> >> set noexpandtab
> >> set shiftwidth=8
> >> set cinoptions=:0,l1,t0,g0
> >> <snip>
> >>
> >
> > Thank you Adam for sharing your vim recipe.
> 
> I believe you can still use your standard vim recipe, then run
> checkpatch.pl on your patches to replace spaces with tabs before
> sending them to upstream.
> 
> Someone else who uses that workflow would need to confirm that works well.
> 
> Greg

Thank you Greg for reminding about this script(checkpatch.pl). I updated
my $HOME/.vimrc file as per Adam's suggestion and generated a patch and
then ran this checkpatch.pl script against my patch and It didn't give
me any error. So I guess the above vim recipe is fine. I've sent that
patch to kernel-janitor group and had kept the maintainer in the CC as
well. I haven't got the reply yet, so I don't know if my patch got
merged or not.

-Amit