John Snow <js...@redhat.com> writes: > On 1/17/20 12:30 PM, Peter Maydell wrote: >> Currently our manual creation includes some .texi files which >> are autogenerated from .hx files by running scripts/hxtool. >> .hx files are a simple format, where where a line is either a >> directive or literal text to be output: >> >> HXCOMM >> -- comment lines, ignored >> STEXI/ETEXI >> -- mark start/end of chunks of text to put into the texinfo output only >> DEFHEADING/ARCHHEADING >> -- appear in the .h file output verbatim (they are defined as C macros); >> for texi output they are parsed to add in header sections >> >> For Sphinx, rather than creating a file to include, the most >> natural way to handle this is to have a small custom Sphinx >> extension which will read the .hx file and process it. So >> instead of "makefile produces foo.texi from foo.hx, qemu-doc.texi >> says '@include foo.texi'", we have "qemu-doc.rst says >> 'hxtool-doc:: foo.hx', the Sphinx extension for hxtool has >> code that runs to handle that Sphinx directive, it reads the .hx >> file and emits the appropriate documentation contents". (This is >> pretty much the same way the kerneldoc extension works right now. >> It also has the advantage that it should work for third-party >> services like readthedocs that expect to build the docs directly >> with sphinx rather than by invoking our makefiles.) >> >> We'll need to update what the markup is to handle having rST >> fragments in it. A very minimalist approach to this would >> simply define a new pair of SRST/ERST directives marking the >> start/end of chunks of rST text to go into the rST only. >> (We might be able to do better than that later, as there's >> some repetition currently going on. But we'll probably get >> a better idea of how easy it is to avoid the repetition if >> we start with a simple conversion.) >> >> Here's what we do with hx files at the moment. We have four: >> >> hmp-commands.hx >> -- defines monitor commands used by monitor.c; generates >> qemu-monitor.texi, used by qemu-doc.texi >> hmp-commands-info.hx >> -- ditto, for the "info" command's subcommand; >> generates qemu-monitor-info.texi, used by qemu-doc.texi >> >> These two use only the "put this in the texi or in the .h file" >> functionality, alternating "raw C code defining an entry for the >> monitor command array" with "lump of raw texi for the docs". >> >> qemu-img-cmds.hx >> -- defines options for qemu-img, used by qemu-img.texi >> >> This uses the STEXI/ETEXI directives to alternate C and texi. >> In the for-the-h-file section the only content is always a DEF() >> macro invocation defining the option; in the texi is only the >> synopsis of the command. This means there's a lot of repetition, >> as the DEF macro includes an argument giving the text of the >> option synopsis, and then the texi also has that synopsis with >> some extra markup. Finally the main qemu-img.texi repeats the >> marked-up synopsis later on when it has the actual main documentation >> of each command. >> >> qemu-options.hx >> -- options for qemu proper, used by qemu-doc.texi >> >> This uses only the DEF, DEFHEADING, ARCHHEADING macros >> in the for-the-h-file sections (and the DEFHEADING/ARCHHEADING >> are read also for texi generation). This also repeats the >> synopsis in the DEF macro and in the texi fragment. >> >> So I think my current view is that we should do the very >> simple "add SRST/ERST directives" to start with: >> * scripts/hxtool needs to recognize them and just ignore >> the text inside them >> * write the hxtool sphinx extension (shouldn't be too hard) >> * conversion of any particular .hx file then involves >> replacing the STEXI ...texi stuff... ETEXI sections with >> SRST ...rst stuff... ERST. There's no need for any >> particular .hx file to support both texi and rst output >> at the same time >> >> I would initially start with qemu-img-cmds.hx, since that's >> pulled in by qemu-img.texi, which we can convert in the >> same way I've been doing qemu-nbd and other standalone-ish >> manpages. The others are part of the big fat qemu-doc.texi, >> which is probably going to be the very last thing we convert... >> > > At one point I did a quick mockup of turning qemu-img-cmds.hx into json > and wrote a small tool I called "pxtool" that was used for generating > all the rest of the subsequent information -- an attempt at getting rid > of .hx files *entirely*. > > The idea at heart was: "Can we remove .hx files and describe everything > in terms of the QAPI schema instead?" > > I'm still a bit partial to that idea, but realize there are some nasty > complexities when it comes to describing the QEMU CLI as a schema. One > of those is that I doubt we even have a full understanding of what the > CLI syntax is at all.
My CLI QAPIfication prototype[*] gets rid of qemu-options.hx. Three more are left: hmp-commands.hx, hmp-commands-info.hx, qemu-img-cmds.hx. No idea whether these could and should be QAPIfied. Going beyond prototype is hard, not least for the reason you mentioned. > Still, I do want to ask: Are we sure we want to double-down on keeping > the .hx files around instead of trying to move to a more generic data > format? One the one hand, I'd prefer to invest as little as practical into .hx. On the other hand, adding more hard dependencies on QAPIfication is not a good idea. What's the stupidest solution that could possibly work now? Is it the one Peter sketched? [*] https://lists.nongnu.org/archive/html/qemu-devel/2017-10/msg00209.html Message-Id: <20171002152552.27999-1-arm...@redhat.com> https://repo.or.cz/qemu/armbru.git/shortlog/refs/heads/qapi-cmdline
