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Date:   Fri, 23 Oct 2020 11:22:26 -0600
From:   Jonathan Corbet <corbet@lwn.net>
To:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc:     Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 01/56] scripts: kernel-doc: fix typedef parsing
Message-ID: <20201023112226.4035e3f7@lwn.net>
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        <d0b2146c4ced3121342583bb3d962628fc96759b.1603469755.git.mchehab+huawei@kernel.org>
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On Fri, 23 Oct 2020 18:32:48 +0200
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:

> The include/linux/genalloc.h file defined this typedef:
> 
> 	typedef unsigned long (*genpool_algo_t)(unsigned long *map,unsigned long size,unsigned long start,unsigned int nr,void *data, struct gen_pool *pool, unsigned long start_addr);
> 
> Because it has a type composite of two words (unsigned long),
> the parser gets the typedef name wrong:
> 
> .. c:macro:: long
> 
>    **Typedef**: Allocation callback function type definition
> 
> Fix the regex in order to accept composite types when
> defining a typedef for a function pointer.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
>  scripts/kernel-doc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/kernel-doc b/scripts/kernel-doc
> index 99cd8418ff8a..311d213ee74d 100755
> --- a/scripts/kernel-doc
> +++ b/scripts/kernel-doc
> @@ -1438,7 +1438,7 @@ sub dump_typedef($$) {
>      $x =~ s@/\*.*?\*/@@gos;	# strip comments.
>  
>      # Parse function prototypes
> -    if ($x =~ /typedef\s+(\w+)\s*\(\*\s*(\w\S+)\s*\)\s*\((.*)\);/ ||
> +    if ($x =~ /typedef\s+(\w+\s*){1,}\(\*\s*(\w\S+)\s*\)\s*\((.*)\);/ ||

I sure wish we could find a way to make all these regexes more
understandable and maintainable.  Reviewing a change like this is ... fun.

Anyway, it seems to work, but it does now include trailing whitespace in
the type portion.  So, for example, from include/linux/xarray.h:

  typedef void (*xa_update_node_t)(struct xa_node *node);

The type is parsed as "void " where it was "void" before.  The only ill
effect I can see is that some non-breaking spaces get inserted into the
HTML output, but perhaps it's worth stripping off that trailing space
anyway?

Thanks,

jon