Re: [PATCH 8/9] CodingStyle: tell people how to split long "for" loops

[David Laight <david.laight.linux@gmail.com>]

On Fri,  9 May 2025 23:34:29 +0300
Alexey Dobriyan <adobriyan@gmail.com> wrote:

> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
>  Documentation/process/coding-style.rst | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
> index e17de69845ff..494ab3201112 100644
> --- a/Documentation/process/coding-style.rst
> +++ b/Documentation/process/coding-style.rst
> @@ -183,7 +183,21 @@ Descendants are always substantially shorter than the parent and
>  are placed substantially to the right.  A very commonly used style
>  is to align descendants to a function open parenthesis.
>  
> -These same rules are applied to function headers with a long argument list.
> +These same rules are applied to function prototypes with a long argument list.
> +
> +Very long ``for`` loops are split at the ``;`` characters making it easier
> +to see which code goes to which clause:
> +
> +.. code-block:: c
> +
> +	for (int i = 0;
> +	     i < N;
> +	     i += 1)
> +	{
> +	}
> +
> +Opening curly is placed on a separate line then to make it easier to tell
> +loop body from iteration clause.

Is that actually the style - I don't remember seeing it.

The location of the { isn't a significant problem with for (;;), it can be
much worse elsewhere.
In reality the 'align with the (' is what causes the problems, either
double indenting (two tabs) or half indent (4 spaces - to annoy anyone who
sets an editor to 4 space tabs) is more readable.

For for (;;) loops I'll normally try moving the initialisation outside the
loop and even put an inverted condition inside the loop to avoid long lines.

If a #define all bets are off :-)

	David



>  
>  However, never break user-visible strings such as printk messages because
>  that breaks the ability to grep for them.