On Fri, 2021-05-14 at 10:21 +0200, Mauro Carvalho Chehab wrote: > Em Wed, 12 May 2021 18:07:04 +0100 > David Woodhouse escreveu: > > > On Wed, 2021-05-12 at 14:50 +0200, Mauro Carvalho Chehab wrote: > > > Such conversion tools - plus some text editor like LibreOffice or similar - have > > > a set of rules that turns some typed ASCII characters into UTF-8 alternatives, > > > for instance converting commas into curly commas and adding non-breakable > > > spaces. All of those are meant to produce better results when the text is > > > displayed in HTML or PDF formats. > > > > And don't we render our documentation into HTML or PDF formats? > > Yes. > > > Are > > some of those non-breaking spaces not actually *useful* for their > > intended purpose? > > No. > > The thing is: non-breaking space can cause a lot of problems. > > We even had to disable Sphinx usage of non-breaking space for > PDF outputs, as this was causing bad LaTeX/PDF outputs. > > See, commit: 3b4c963243b1 ("docs: conf.py: adjust the LaTeX document output") > > The afore mentioned patch disables Sphinx default behavior of > using NON-BREAKABLE SPACE on literal blocks and strings, using this > special setting: "parsedliteralwraps=true". > > When NON-BREAKABLE SPACE were used on PDF outputs, several parts of > the media uAPI docs were violating the document margins by far, > causing texts to be truncated. > > So, please **don't add NON-BREAKABLE SPACE**, unless you test > (and keep testing it from time to time) if outputs on all > formats are properly supporting it on different Sphinx versions. And there you have a specific change with a specific fix. Nothing to do with whether NON-BREAKABLE SPACE is ∉ ASCII, and *certainly* nothing to do with the fact that, like *every* character in every kernel file except the *binary* files, it's representable in UTF-8. By all means fix the specific characters which are typographically wrong or which, like NON-BREAKABLE SPACE, cause problems for rendering the documentation. > Also, most of those came from conversion tools, together with other > eccentricities, like the usage of U+FEFF (BOM) character at the > start of some documents. The remaining ones seem to came from > cut-and-paste. ... or which are just entirely redundant and gratuitous, like a BOM in an environment where all files are UTF-8 and never 16-bit encodings anyway. > > > While it is perfectly fine to use UTF-8 characters in Linux, and specially at > > > the documentation, it is better to stick to the ASCII subset on such > > > particular case, due to a couple of reasons: > > > > > > 1. it makes life easier for tools like grep; > > > > Barely, as noted, because of things like line feeds. > > You can use grep with "-z" to seek for multi-line strings(*), Like: > > $ grep -Pzl 'grace period started,\s*then' $(find Documentation/ -type f) > Documentation/RCU/Design/Data-Structures/Data-Structures.rst Yeah, right. That works if you don't just use the text that you'll have seen in the HTML/PDF "grace period started, then", and if you instead craft a *regex* for it, replacing the spaces with '\s*'. Or is that [[:space:]]* if you don't want to use the experimental Perl regex feature? $ grep -zlr 'grace[[:space:]]\+period[[:space:]]\+started,[[:space:]]\+then' Documentation/RCU Documentation/RCU/Design/Data-Structures/Data-Structures.rst And without '-l' it'll obviously just give you the whole file. No '-A5 -B5' to see the surroundings... it's hardly a useful thing, is it? > (*) Unfortunately, while "git grep" also has a "-z" flag, it > seems that this is (currently?) broken with regards of handling multilines: > > $ git grep -Pzl 'grace period started,\s*then' > $ Even better. So no, multiline grep isn't really a commonly usable feature at all. This is why we prefer to put user-visible strings on one line in C source code, even if it takes the lines over 80 characters — to allow for grep to find them. > > > 2. they easier to edit with the some commonly used text/source > > > code editors. > > > > That is nonsense. Any but the most broken and/or anachronistic > > environments and editors will be just fine. > > Not really. > > I do use a lot of UTF-8 here, as I type texts in Portuguese, but I rely > on the US-intl keyboard settings, that allow me to type as "'a" for á. > However, there's no shortcut for non-Latin UTF-codes, as far as I know. > > So, if would need to type a curly comma on the text editors I normally > use for development (vim, nano, kate), I would need to cut-and-paste > it from somewhere[1]. That's entirely irrelevant. You don't need to be able to *type* every character that you see in front of you, as long as your editor will render it correctly and perhaps let you cut/paste it as you're editing the document if you're moving things around. > [1] If I have a table with UTF-8 codes handy, I could type the UTF-8 > number manually... However, it seems that this is currently broken > at least on Fedora 33 (with Mate Desktop and US intl keyboard with > dead keys). > > Here, U is not working. No idea why. I haven't > test it for *years*, as I din't see any reason why I would > need to type UTF-8 characters by numbers until we started > this thread. Please provide the bug number for this; I'd like to track it. > But even in the best case scenario where I know the UTF-8 and > U works, if I wanted to use, for instance, a curly > comma, the keystroke sequence would be: > > U201csome stringU201d > > That's a lot harder than typing and has a higher chances of > mistakenly add a wrong symbol than just typing: > > "some string" > > Knowing that both will produce *exactly* the same output, why > should I bother doing it the hard way? Nobody's asked you to do it the "hard way". That's completely irrelevant to the discussion we were having. > Now, I'm not arguing that you can't use whatever UTF-8 symbol you > want on your docs. I'm just saying that, now that the conversion > is over and a lot of documents ended getting some UTF-8 characters > by accident, it is time for a cleanup. All text documents are *full* of UTF-8 characters. If there is a file in the source code which has *any* non-UTF8, we call that a 'binary file'. Again, if you want to make specific fixes like removing non-breaking spaces and byte order marks, with specific reasons, then those make sense. But it's got very little to do with UTF-8 and how easy it is to type them. And the excuse you've put in the commit comment for your patches is utterly bogus.