[Mesa-dev] [RFC 08/21] mesa/extensions: Replace extension::api_set with ::version

[Matt Turner]

On Thu, Oct 22, 2015 at 11:24 AM, Chad Versace <chad.versace at intel.com> wrote:
> On Mon 19 Oct 2015, Nanley Chery wrote:
>> From: Nanley Chery <nanley.g.chery at intel.com>
>>
>> The api_set field has no users outside of _mesa_extension_supported().
>> Remove it and allow the version field to take its place.
>>
>> The brunt of the transformation was performed with the following vim commands:
>> s/\(GL [^,]\+\),\s*\d*,\s*\d*\(,\s*\d*\)\(,\s*\d*\)/\1, GLL, GLC\2\3/g
>> s/\(GLL [^,]\+\)\,\s*\d*/\1, GLL/g
>> s/\(GLC [^,]\+\)\(,\s*\d*\),\s*\d*\(,\s*\d*\)\(,\s*\d*\)/\1\2, GLC\3\4/g
>> s/\( ES1[^,]*\)\(,\s*\(\w\|\d\)\+\)\(,\s*\(\w\|\d\)\+\),\s*\d*/\1\2\4, ES1/g
>> s/\( ES2[^,]*\)\(,\s*\(\w\|\d\)\+\)\(,\s*\(\w\|\d\)\+\)\(,\s*\(\w\|\d\)\+\),\s*\d*/\1\2\4\6, ES2/g
>>
>> Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
>> ---
>>  src/mesa/main/extensions.c       |  21 +-
>>  src/mesa/main/extensions_table.h | 636 ++++++++++++++++++++-------------------
>>  2 files changed, 326 insertions(+), 331 deletions(-)
>
> [...]
>
>> diff --git a/src/mesa/main/extensions_table.h b/src/mesa/main/extensions_table.h
>
> [...]
>
>> +#define GLL 0
>> +#define GLC 0
>> +#define ES1 0
>> +#define ES2 0
>> +#define  x ~0
>
>> +EXT(EXT_abgr                                , dummy_true                             , GLL, GLC,  x ,  x , 1995)
>> +EXT(EXT_bgra                                , dummy_true                             , GLL,  x ,  x ,  x , 1995)
>> +EXT(EXT_blend_color                         , EXT_blend_color                        , GLL,  x ,  x ,  x , 1995)
>> +EXT(EXT_blend_equation_separate             , EXT_blend_equation_separate            , GLL, GLC,  x ,  x , 2003)
>> +EXT(EXT_blend_func_separate                 , EXT_blend_func_separate                , GLL,  x ,  x ,  x , 1999)
>> +EXT(EXT_discard_framebuffer                 , dummy_true                             ,  x ,  x , ES1, ES2, 2009)
>> +EXT(EXT_blend_minmax                        , EXT_blend_minmax                       , GLL,  x , ES1, ES2, 1995)
>
> I like the idea of this patch. It's a cleanup that needs to happen. But,
> the little details confuse me.
>
> When I see GLL, GLC, ES1, and ES2 as the entries in the version columns,
> the entries confuse me because I expect the tokens to all have different
> values. Otherwise, why would the tokens have different names?
>
> I think the table would be less confusing if you used the macros
>   #define x ~0
>   #define Y 0
> or
>   #define n ~0
>   #define Y 0
> or
>   #define n ~0
>   #define y 0
> or anything like that. I like the n/Y the best because the letters are
> mnenomic and the contrast of uppercase to lowercase is easy to see when
> scanning the table.

I get what you're saying, but Nanley's code as is allows you to see
exactly which APIs an extension exists in without looking up the
column headers.

With your approach, a reader would need to know that the columns are
ordered GL compat, GL core, ES1, ES2, if I've understood your
suggestion.