Re: [dpdk-dev] [PATCH] doc/contributing/documentation: add info about including code

[Thomas Monjalon <thomas@monjalon.net>]

04/05/2021 13:15, Ferruh Yigit:
> On 5/4/2021 11:44 AM, Thomas Monjalon wrote:
> > 04/05/2021 12:35, Ferruh Yigit:
> >> On 5/4/2021 10:59 AM, Thomas Monjalon wrote:
> >>> 04/05/2021 11:32, Burakov, Anatoly:
> >>>> On 03-May-21 10:02 PM, Thomas Monjalon wrote:
> >>>>> 21/04/2021 11:11, Conor Walsh:
> >>>>>> +  The following will include a snippet from the skeleton sample app::
> >>>>>> +
> >>>>>> +      .. literalinclude:: ../../../examples/skeleton/basicfwd.c
> >>>>>> +        :language: c
> >>>>>> +        :start-after: Display the port MAC address.
> >>>>>> +        :end-before: Enable RX in promiscuous mode for the Ethernet device.
> >>>>>> +        :dedent: 1
> >>>>>
> >>>>> I would prefer indenting the options with 3 spaces
> >>>>> to make them aligned with literalinclude.
> >>>>>
> >>>>> [...]
> >>>>>> +* ``start-after`` and ``end-before`` can use any text within a given file,
> >>>>>> +  however it may be difficult to find unique text within your code to mark the
> >>>>>> +  start and end of your snippets. In these cases, it is recommended to include
> >>>>>> +  explicit tags in your code to denote these locations for documentation purposes.
> >>>>>> +
> >>>>>> +  This can be done as follows:
> >>>>>> +
> >>>>>> +  .. code-block:: c
> >>>>>> +
> >>>>>> +    /* #guide_doc: Example feature being documented. */
> >>>>>> +    ...
> >>>>>> +    /* #guide_doc: End of example feature being documented. */
> >>>>>
> >>>>> I think we can standardize this usage in a beautiful syntax.
> >>>>> My proposal, using the scissor sign:
> >>>>>
> >>>>>      /* Foo bar >8 */
> >>>>>      foo(bar);
> >>>>>      /* 8< End of foo bar */
> >>>>>
> >>>>>      .. literalinclude:: foobar.c
> >>>>>         :language: C
> >>>>>         :start-after: Foo bar >8
> >>>>>         :end-before: 8< End of foo bar
> >>>>>
> >>>>> Another idea:
> >>>>>
> >>>>>      /*~ Foo bar */
> >>>>>      foo(bar);
> >>>>>      /*~ End of foo bar */
> >>>>>
> >>>>>      .. literalinclude:: foobar.c
> >>>>>         :language: C
> >>>>>         :start-after: ~ Foo bar
> >>>>>         :end-before: ~ End of foo bar
> >>>>>
> >>>>> Maybe we don't need any markup for the start line and keep it natural:
> >>>>>
> >>>>>      /* Foo bar */
> >>>>>      foo(bar);
> >>>>>      /* end: Foo bar */
> >>>>>
> >>>>>      .. literalinclude:: foobar.c
> >>>>>         :language: C
> >>>>>         :start-after: Foo bar
> >>>>>         :end-before: end: Foo bar
> >>>>
> >>>> Not having markup will 1) risk people accidentally "fixing" or otherwise 
> >>>> modifying comments, and 2) has bigger potential for collisions elsewhere 
> >>>> in the comments. While these aren't big risks, IMO it should be 
> >>>> explicitly obvious that a comment is not just a comment but a marker docs.
> >>>>
> >>>> Having named tags like in the original proposal is the most explicit 
> >>>> version of the above, which is why i favor it, but i think it's OK to 
> >>>> have a lighter-weight syntax (e.g. with scissors for example), however i 
> >>>> don't think it's a good idea to leave things implicit like your last 
> >>>> suggestion.
> >>>
> >>> I think the first comment is not only for code extraction,
> >>> but also for code reader, that's why I think it's good to keep it natural.
> >>
> >> +1 to Anatoly's comment, to make it obvious to the reader of the code that the
> >> comment is used for documentation purposes and use explicit syntax for it.
> > 
> > So you assume the comment is only for doc extraction?
> > I think it can be a real comment, otherwise we'll need to have
> > 2 lines: 1 for doc extraction, 1 for code comment.
> > 
> 
> I see your point, for the cases that there is already a comment before (or
> after) the code, will it be too bad to have multiple lines, something like:
> 
> /* Actual comment
>  * More details
>  *
>  * explicit marker */
> 
> 
> I think explicit marker has the advantage of:
> - Whoever updating the comment will know that it is a marker for the
> documentation and be careful on update
> - Whoever updating the code between the markers, know that it may be required to
> re-visit the relevant documentation and update it because of code change
> - Whoever reading the code will know that part is in a documentation, and may be
> interested to go and check the relevant documentation
> - Whoever reading the code, and not very familiar with DPDK convention, still
> can understand what that comment is for and benefit from above

I understand these points.
But I'm afraid the proposed syntax #guide_doc:
is not so obvious for everybody.

I'm sure there can be a better syntax.