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. > 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
