On Mon, 29 Mar 2021, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > On Mon, Mar 29, 2021 at 09:33:30PM +0300, Jani Nikula wrote: >> On Mon, 29 Mar 2021, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: >> > So here's my "modest proposal": >> > >> > - Similar to our ".. kernel-doc::" invocation in .rst files, handle >> > ".. rustdoc::" (insert weeks of hacking here) >> > - Now add ".. rst-doc::" which parses .c files like [1] kernel-doc >> > does, but interprets a different style of comment and actually does >> > most of the repetitive boring bits for you. >> >> As a hobby, I've written a Sphinx extension to use Clang to parse the >> code and extract pure reStructuredText documentation comments with >> minimal conversions [1]. No additional syntax. Just use reStructuredText >> for everything instead of inventing your own. >> >> I'm not proposing to use that in kernel, at all. It was more like a >> diversion from the kernel documentation. > > Actually, that looks like my proposal, except that it uses the same /** > as kernel-doc, so you can't tell whether a comment is intended to be > interpreted by kernel-doc or hawkmoth. > > https://github.com/jnikula/hawkmoth/blob/master/test/example-70-function.c > > If the introduction were "/*rST" instead of "/**", would we have > consensus? It gives us a path to let people intermix kernel-doc and > hawkmoth comments in the same file, which would be amazing. If you want to allow two syntaxes for documentation comments (current kernel-doc and pure reStructuredText with just the comment markers and indentation removed) I think the natural first step would be to modify kernel-doc the perl script to support that. It would probably even be trivial. Hawkmoth uses Clang for parsing, with none of the kernel specific stuff that kernel-doc has, such as EXPORT_SYMBOL(). It makes sense for a pet project with a clean break. I don't know if anyone has the bandwidth or desire to re-implement the kernel specific stuff on top of Clang. (I know I don't, I started the project because I wanted that clean break to begin with!) The real question is, is it a good idea to support multiple formats at all? (N.b. I'm not a fan of extending the kernel-doc syntax either.) BR, Jani. > >> But based on my experience with the old and new kernel documentation >> systems and the hobby one, the one takeaway is to not create new >> syntaxes, grammars, parsers, or preprocessors to be maintained by the >> kernel community. Just don't. Take what's working and supported by other >> projects, and add the minimal glue using Sphinx extensions to put it >> together, and no more. >> >> Of course, we couldn't ditch kernel-doc the script, but we managed to >> trim it down quite a bit. OTOH, there have been a number of additions >> outside of Sphinx in Makefiles and custom tools in various languages >> that I'm really not happy about. It's all too reminiscient of the old >> DocBook toolchain, while Sphinx was supposed to be the one tool to tie >> it all together, partially chosen because of the extension support. >> >> >> BR, >> Jani. >> >> >> [1] https://github.com/jnikula/hawkmoth >> >> >> > >> > For example, xa_load: >> > >> > /** >> > * xa_load() - Load an entry from an XArray. >> > * @xa: XArray. >> > * @index: index into array. >> > * >> > * Context: Any context. Takes and releases the RCU lock. >> > * Return: The entry at @index in @xa. >> > */ >> > void *xa_load(struct xarray *xa, unsigned long index) >> > >> > //rST >> > // Load an entry from an XArray. >> > // >> > // :Context: Any context. Takes and releases the RCU lock. >> > // :Return: The entry in `xa` at `index`. >> > void *xa_load(struct xarray *xa, unsigned long index) >> > >> > (more complex example below [2]) >> > >> > Things I considered: >> > >> > - Explicitly document that this is rST markup instead of Markdown or >> > whatever. >> > - Don't repeat the name of the function. The tool can figure it out. >> > - Don't force documenting each parameter. Often they are obvious >> > and there's really nothing interesting to say about the parameter. >> > Witness the number of '@foo: The foo' (of type struct foo) that we >> > have scattered throughout the tree. It's not that the documenter is >> > lazy, it's that there's genuinely nothing to say here. >> > - Use `interpreted text` to refer to parameters instead of *emphasis* or >> > **strong emphasis**. The tool can turn that into whatever markup >> > is appropriate. >> > - Use field lists for Context and Return instead of sections. The markup >> > is simpler to use, and I think the rendered output is better. >> > >> > [1] by which i mean "in a completely different way from, but similar in >> > concept" >> > >> > [2] More complex example: >> > >> > /** >> > * xa_store() - Store this entry in the XArray. >> > * @xa: XArray. >> > * @index: Index into array. >> > * @entry: New entry. >> > * @gfp: Memory allocation flags. >> > * >> > * After this function returns, loads from this index will return @entry. >> > * Storing into an existing multi-index entry updates the entry of every index. >> > * The marks associated with @index are unaffected unless @entry is %NULL. >> > * >> > * Context: Any context. Takes and releases the xa_lock. >> > * May sleep if the @gfp flags permit. >> > * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry >> > * cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation >> > * failed. >> > */ >> > void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) >> > >> > //rST >> > // Store an entry in the XArray. >> > // >> > // After this function returns, loads from `index` will return `entry`. >> > // Storing into an existing multi-index entry updates the entry of every index. >> > // The marks associated with `index` are unaffected unless `entry` is ``NULL``. >> > // >> > // :Context: Any context. Takes and releases the xa_lock. >> > // May sleep if the `gfp` flags permit. >> > // :Return: The old entry at this index on success, xa_err(-EINVAL) if `entry` >> > // cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation >> > // failed. >> > void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) >> > >> >> -- >> Jani Nikula, Intel Open Source Graphics Center -- Jani Nikula, Intel Open Source Graphics Center
