[R-pkg-devel] Package Encoding and Literal Strings

joris m@iii@g oii jorisgoose@@@i joris m@iii@g oii jorisgoose@@@i
Thu Dec 17 18:43:08 CET 2020 

On Thu, 17 Dec 2020 at 18:22, Tomas Kalibera <tomas.kalibera using gmail.com>
wrote:

> On 12/17/20 5:17 PM, joris using jorisgoosen.nl wrote:
>
>
>
> On Thu, 17 Dec 2020 at 10:46, Tomas Kalibera <tomas.kalibera using gmail.com>
> wrote:
>
>> On 12/16/20 11:07 PM, joris using jorisgoosen.nl wrote:
>> > David,
>> >
>> > Thanks for the response!
>> >
>> > So the problem is a bit worse then just setting `encoding="UTF-8"` on
>> > functions like readLines.
>> > I'll describe our setup a bit:
>> > So we run R embedded in a separate executable and through a whole bunch
>> of
>> > C(++) magic get that to the main executable that runs the actual
>> interface.
>> > All the code that isn't R basically uses UTF-8. This works good and
>> we've
>> > made sure that all of our source code is encoded properly and I've
>> verified
>> > that for this particular problem at least my source file is definitely
>> > encoded in UTF-8 (Ive checked a hexdump).
>> >
>> > The simplest solution, that we initially took, to get R+Windows to
>> > cooperate with everything is to simply set the locale to "C" before
>> > starting R. That way R simply assumes UTF-8 is native and everything
>> worked
>> > splendidly. Until of course a file needs to be opened in R that contains
>> > some non-ASCII characters. I noticed the problem because a korean user
>> had
>> > hangul in his username and that broke everything. This because R was
>> trying
>> > to convert to a different locale than Windows was using.
>>
>> Setting locale to "C" does not make R assume UTF-8 is the native
>> encoding, there is no way to make UTF-8 the current native encoding in R
>> on the current builds of R on Windows. This is an old limitation of
>> Windows, only recently fixed by Microsoft in recent Windows 10 and with
>> UCRT Windows runtime (see my blog post [1] for more - to make R support
>> this we need a new toolchain to build R).
>>
>> If you set the locale to C encoding, you are telling R the native
>> encoding is C/POSIX (essentially ASCII), not UTF-8. Encoding-sensitive
>> operations, including conversions, including those conversions that
>> happen without user control e.g. for interacting with Windows, will
>> produce incorrect results (garbage) or in better case errors, warnings,
>> omitted, substituted or transliterated characters.
>>
>> In principle setting the encoding via locale is dangerous on Windows,
>> because Windows has two current encodings, not just one. By setting
>> locale you set the one used in the C runtime, but not the other one used
>> by the system calls. If all code (in R, packages, external libraries)
>> was perfect, this would still work as long as all strings used were
>> representable in both encodings. For other strings it won't work, and
>> then code is not perfect in this regard, it is usually written assuming
>> there is one current encoding, which common sense dictates should be the
>> case. With the recent UTF-8 support ([1]), one can switch both of these
>> to UTF-8.
>>
>
> Well, this is exactly why I want to get rid of the situation. But this
> messes up the output because everything else expects UTF-8 which is why I'm
> looking for some kind of solution.
>
>
>
>> > The solution I've now been working on is:
>> > I took the sourcecode of R 4.0.3 and changed the backend of "gettext" to
>> > add an `encoding="something something"` option. And a bit of extra stuff
>> > like `bind_textdomain_codeset` in case I need to tweak the
>> codeset/charset
>> > that gettext uses.
>> > I think I've got that working properly now and once I solve the problem
>> of
>> > the encoding in a pkg I will open a bugreport/feature-request and I'll
>> add
>> > a patch that implements it.
>>
>> A number of similar "shortcuts" have been added to R in the past, but
>> they may the code more complex, harder to maintain and use, and can't
>> realistically solve all of these problems, anyway. Strings will
>> eventually be assumed to be in what is the current native encoding by
>> the C library. In R, any external code R uses, or code R packages use.
>> Now that Microsoft finally is supporting UTF-8, the way to get out of
>> this is switching to UTF-8. This needs only small changes to R source
>> code compared to those "shortcuts" (or to using UTF-16LE). I'd be
>> against polluting the code with any more "shortcuts".
>>
>
> I think the addition of " bind_textdomain_codeset" is not strictly
> necessary and can be left out. Because I think setting an environment
> variable as "OUTPUT_CHARSET=UTF-8" gives the same result for us.
> The addition of the "encoding" option to the internal "do_gettext" is just
> a few lines of code and I also undid some duplication between do_gettext
> and do_ngettext. Which should make it easier to maintain. But all of that
> is moot if there is no way to keep the literal strings from sources in
> UTF-8 anyhow.
>
> Before starting on this I did actually read your blogpost about UTF-8
> several times and it seems like the best way forward. Not to mention it
> would make my life easier and me happier when I can stop worrying about
> Windows/Dos codepages!
> Thank you for your work on it indeed!
>
> But my problem with that is that a number of people still use an older
> version of windows and your solution won't work there. Which would mean
> that we either drop support for them or they would have to live with either
> weirdlooking translations. Or I have to go back to the suboptimal solution
> of the "C" locale which I really do want to avoid. Because as you said it
> breaks other stuff in unpredictable ways.
>
> The number of people using too old version of Windows should be small when
> this could become ready for production. Windows 8.1. is still supported,
> but there is the free upgrade to Windows 10 (also from no longer supported
> Windows 7), so this should not be a problem for desktop machines. It will
> be a problem for servers.
>
Well, I would not expect anyone to use a GUI-heavy application meant for
researchers on a server anyway so that would be fine.

>
>
>> > The problem I'm stuck with now is simply this:
>> > I have an R pkg here that I want to test the translations with and the
>> code
>> > is definitely saved as UTF-8, the package has "Encoding: UTF-8" in the
>> > DESCRIPTION and it all loads and works. The particular problem I have is
>> > that the R code contains literally: `mathotString <- "Mathôt!"`
>> > The actual file contains the hexadecimal representation of ô as proper
>> > utf-8: "0xC3 0xB4" but R turns it into: "0xf4".
>> > Seemingly on loading the package, because I haven't done anything with
>> it
>> > except put it in my debug c-function to print its contents as
>> > hexadecimals...
>> >
>> > The only thing I want to achieve here is that when R loads the package
>> it
>> > keeps those strings in their original UTF-8 encoding, without
>> converting it
>> > to "native" or the strange unicode codepoint it seemingly placed in
>> there
>> > instead. Because otherwise I cannot get gettext to work fully in UTF-8
>> mode.
>> >
>> > Is this already possible in R?
>>
>> In principle, working with strings not representable in the current
>> encoding is not reliable (and never will be). It can still work in some
>> specific cases and uses. Parsing a UTF-8 string literal from a file,
>> with correctly declared encoding as documented in WRE, should work at
>> least in single-byte encodings. But what happens after that string is
>> parsed is another thing. The parsing is based internally on using these
>> "shortcuts", that is lying to a part of the parser about the encoding,
>> and telling the rest of the parser that it is really something else (not
>> native, but UTF-8).
>
>
> So the reason the string literals are turned into the local encoding is
> because setting the "Encoding" on a package is essentially a hack?
>
> String literals may be turned into local encoding because that is how
> R/packages/external software is written - it needs native encoding. Hacks
> here come when such code is given a string not in the local encoding,
> assuming that under some conditions such code will work. This includes a
> part of the parser and a hack to implement argument "encoding" of
> "parse()", which allows to parse (non-representable) UTF-8 strings when
> running in a single-byte locale such as latin 1 (see ?parse).
>
So the same `parse` function is used for loading a package?
Because in that case I wonder if the "Encoding" option in "DESCRIPTION" is
handled the same as `encoding=` in parse.

?parse states:
> Character strings in the result will have a declared encoding if encoding
is "latin1" or "UTF-8", or if text is supplied with every element of known
encoding in a Latin-1 or UTF-8 locale.

The sentence is a bit hard for me personally to parse but I interpret that
first part to mean that if "encoding" is specified as "UTF-8" all the
character string in the result will also have that encoding.
Is that a correct interpretation?
Because if so I do believe I found a problem and I will try to make a
minimal reproducable example.


>
>
>> The part that is being "lied to" may get confused or
>> not. It would not when the real native encoding is say latin1, a common
>> case in the past for which the hack was created, but it might when it is
>> a double-byte encoding that conflicts with the text being parsed in
>> dangerous ways. This is also why this hack only makes sense for string
>> literals (and comments), and still only to a limit as the strings may be
>> misinterpreted later after parsing.
>>
>
> Well our case is entirely limited to string literals that are presented to
> the user through an all-utf-8 interface.
> So I would assume not of the edge-cases would come into play.
> Any systempaths and things like that would still be in local encoding.
>
>
>
>
>> So a really short summary is: you can only reliably use strings
>> representable in the current encoding in R, and that encoding cannot be
>> UTF-8 on Windows in released versions of R. There is an experimental
>> version, see [1], if you could experiment with that and see whether that
>> might work for your applications, could try to find and report bugs
>> there (e.g. to me directly), that would be useful.
>>
>
> So when I read in certain R documentation that string can have an "UTF-8"
> encoding in R this is not true?
> As in, when I read documentation such as
> https://stat.ethz.ch/R-manual/R-devel/library/base/html/Encoding.html it
> really seems to indicate to me that UTF-8 is in fact supported in R on
> windows.
> My assumption was that R uses `translateChar` internally to make sure it
> is in the right encoding before interfacing with the OS and other places
> where this might matter.
>
> UTF-8 is supported in R on Windows in many ways, as documented. As long as
> you are using UTF-8 strings representable in the current encoding, so that
> they can be converted to native encoding and back without problems, you are
> fine, R will do the conversions as needed. The troubles come when such
> conversion is not possible. In the example of the parser, without the
> "encoding=" argument to "parse()", the parser will just work on any text
> you give to it, even when the text is in UTF-8: it will work by first
> converting to native encoding and then doing the parsing, no hacks
> involved. When interacting with external software, you'd just tell R to
> provide the strings in the encoding needed by that external software, so
> possibly UTF-8, so possibly convert, but all would work fine. The problem
> are characters not representable in the native encoding.
>
Exactly, I want to be able to support chinese etc as well while running in
a west-european locale.
This is also what mislead me, because I thought it was actually reading it
like that but the character is part of my local locale so I didn't notice
it. Especially as it was being printed correctly. I only noticed after
printing the literal values.


>
>
>> If you find behavior re encodings in released versions of R that
>> contradicts the current documentation, please report with a minimal
>> reproducible example, such cases should be fixed (even though sometimes
>> the "fix" would be just changing the documentation, the effort really
>> should be now for supporting UTF-8 for real). Specifically with
>> "mathotString", you might try creating  an example that does not include
>> any package (just calls to parse with encoding options set), only then
>> gradually adding more of package loading if that does not reproduce. It
>> would be important to know the current encoding (sessionInfo, l10n_info).
>>
>
> Well, the reason I mailed the mailing list was because I couldn't for the
> life of me find any documentation that told me anything in particular about
> how literal strings are supposed to be stored in memory. But it just seems
> logical to me that if R already supports parsing and loading a package
> encoded with UTF-8 and it supports having UTF-8 strings in memory next to
> strings in native encoding the most straightforward way of loading this
> literal strings would be in UTF-8.
>
> You mean the memory representation? For that there would be R Internals
> and the sources, essentially there are CHARSXP objects which include an
> encoding tag (UTF-8, Latin-1 or native) and the raw bytes. But you would
> not access these objects directly, instead use translateChar() if you
> needed strings them in native encoding or translateCharUTF8() if in UTF-8,
> and this is documented in Writing R Extensions.
>
Exactly, because gettext operates in C and the source files for that are
also in utf-8 the actual memory representation of the string in R needs to
be identical, otherwise it won't work.

> I think it would be really good if you could provide a complete, minimal
> reproducible example of your problem. It may be there is some
> misunderstanding, especially if you are working with characters
> representable in the current encoding, there should be no problem.
>
It depends on if I now understand ?parse correctly in that it should have
the strings in a package that is parsed with the specified encoding in that
encoding or not. As I wondered above.

> I would love to use the new version of R that supports properly
> interfacing with windows 10.
> And given that the only other supported version of Windows is 8.1 and
> barely anyone uses it. So it might be worth dropping support for that.
> I just hoped I could find a workable solution without such a step.
>
> I understand, also it may take a bit of time before this would become
> stable.
>
Of course.
Hopefully I can still use my current workaround for the time being and then
switch over to the UTF-8 ready version if it becomes production-ready at
some point.

Cheers,
Joris

Best
> Tomas
>
>
> Cheers,
> Joris
>
>
>>
>> Best,
>> Tomas
>>
>> [1]
>>
>> https://developer.r-project.org/Blog/public/2020/07/30/windows/utf-8-build-of-r-and-cran-packages/index.html
>>
>> >
>> > Cheers,
>> > Joris
>>
>> >
>> >
>> > On Wed, 16 Dec 2020 at 20:15, David Bosak <dbosak01 using gmail.com> wrote:
>> >
>> >> Joris:
>> >>
>> >>
>> >>
>> >> I’ve fought with encoding problems on Windows a lot.  Here are some
>> >> general suggestions.
>> >>
>> >>
>> >>
>> >>     1. Put “@encoding UTF-8” on any Roxygen comments.
>> >>     2. Put “encoding = “UTF-8” on any functions like writeLines or
>> >>     readLines that read/write to a text file.
>> >>     3. This post:
>> >>
>> https://kevinushey.github.io/blog/2018/02/21/string-encoding-and-r/
>> >>
>> >>
>> >>
>> >> If you have a more specific problem, please describe and we can try to
>> >> help.
>> >>
>> >>
>> >>
>> >> David
>> >>
>> >>
>> >>
>> >> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
>> >> Windows 10
>> >>
>> >>
>> >>
>> >> *From: *joris using jorisgoosen.nl
>> >> *Sent: *Wednesday, December 16, 2020 1:52 PM
>> >> *To: *r-package-devel using r-project.org
>> >> *Subject: *[R-pkg-devel] Package Encoding and Literal Strings
>> >>
>> >>
>> >>
>> >> Hello All,
>> >>
>> >>
>> >>
>> >> Some context, I am one of the programmers of a software pkg (
>> >>
>> >> https://jasp-stats.org/) that uses an embedded instance of R to do
>> >>
>> >> statistics. And make that a bit easier for people who are intimidated
>> by R
>> >>
>> >> or like to have something more GUI oriented.
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> We have been working on translating the interface but ran into several
>> >>
>> >> problems related to encoding of strings. We prefer to use UTF-8 for
>> >>
>> >> everything and this works wonderful on unix systems, as is to be
>> expected.
>> >>
>> >>
>> >>
>> >> Windows however is a different matter. Currently I am working on some
>> local
>> >>
>> >> changes to "do_gettext" and some related internal functions of R to be
>> able
>> >>
>> >> to get UTF-8 encoded output from there.
>> >>
>> >>
>> >>
>> >> But I ran into a bit of a problem and I think this mailinglist is
>> probably
>> >>
>> >> the best place to start.
>> >>
>> >>
>> >>
>> >> It seems that if I have an R package that specifies "Encoding: UTF-8"
>> in
>> >>
>> >> DESCRIPTION the literal strings inside the package are converted to the
>> >>
>> >> local codeset/codepage regardless of what I want.
>> >>
>> >>
>> >>
>> >> Is it possible to keep the strings in UTF-8 internally in such a pkg
>> >>
>> >> somehow?
>> >>
>> >>
>> >>
>> >> Best regards,
>> >>
>> >> Joris Goosen
>> >>
>> >> University of Amsterdam
>> >>
>> >>
>> >>
>> >>                  [[alternative HTML version deleted]]
>> >>
>> >>
>> >>
>> >> ______________________________________________
>> >>
>> >> R-package-devel using r-project.org mailing list
>> >>
>> >> https://stat.ethz.ch/mailman/listinfo/r-package-devel
>> >>
>> >>
>> >>
>> >       [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-package-devel using r-project.org mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-package-devel
>>
>>
>>
>

	[[alternative HTML version deleted]]

More information about the R-package-devel mailing list