[R-pkg-devel] Package Encoding and Literal Strings
Tomas Kalibera
tom@@@k@||ber@ @end|ng |rom gm@||@com
Fri Dec 18 18:05:29 CET 2020
Hi Joris,
thanks for the example. You can actually simply have Test.R assign the
two variables and then run
Encoding(utf8StringsPkg1::mathotString)
charToRaw(utf8StringsPkg1::mathotString)
Encoding(utf8StringsPkg1::tao)
charToRaw(utf8StringsPkg1::tao)
I tried on Linux, Windows/UTF-8 (the experimental version) and
Windows/latin-1 (released version). In all cases, both strings are
converted to native encoding. The mathotString is converted to latin-1
fine, because it is representable there. The tao string when running in
latin-1 locale gets the escapes <xx>:
"<e9><99><b6><e5><be><b7><e5><ba><86>"
Btw, the parse(,encoding="UTF-8") hack works, when you parse the
modified Test.R file (with the two assignments), and eval the output,
you will get those strings in UTF-8. But when you don't eval and print
the parse tree in Rgui, it will not be printed correctly (again a
limitation of these hacks, they could only do so much).
When accessing strings from C, you should always be prepared for any
encoding in a CHARSXP, so when you want UTF-8, use "translateCharUTF8()"
instead of "CHAR()". That will work fine on representable strings like
mathotString, and that is conceptually the correct way to access them.
Strings that cannot be represented in the native encoding like tao will
get the escapes, and so cannot be converted back to UTF-8. This is not
great, but I see it was the case already in 3.6 (so not a recent
regression) and I don't think it would be worth the time trying to fix
that - as discussed earlier, only switching to UTF-8 would fix all of
these translations, not just one. Btw, the example works fine on the
experimentation UTF-8 build on Windows.
I am sorry there is not a simple fix for non-representable characters.
Best
Tomas
On 12/18/20 1:53 PM, joris using jorisgoosen.nl wrote:
> Hello Tomas,
>
> I have made a minimal example that demonstrates my problem:
> https://github.com/JorisGoosen/utf8StringsPkg
>
> This package is encoded in UTF-8 as is Test.R. There is a little Rcpp
> function in there I wrote that displays the bytes straight from R's
> CHAR to be sure no conversion is happening.
> I would expect that the mathotString had "C3 B4" for "ô" but instead
> it gets "F4". As you can see when you run
> `utf8StringsPkg::testutf8_in_locale()`.
>
> Cheers,
> Joris
>
>
>
> On Fri, 18 Dec 2020 at 11:48, Tomas Kalibera <tomas.kalibera using gmail.com
> <mailto:tomas.kalibera using gmail.com>> wrote:
>
> On 12/17/20 6:43 PM, joris using jorisgoosen.nl
> <mailto:joris using jorisgoosen.nl> wrote:
>>
>>
>> On Thu, 17 Dec 2020 at 18:22, Tomas Kalibera
>> <tomas.kalibera using gmail.com <mailto:tomas.kalibera using gmail.com>> wrote:
>>
>> On 12/17/20 5:17 PM, joris using jorisgoosen.nl
>> <mailto:joris using jorisgoosen.nl> wrote:
>>>
>>>
>>> On Thu, 17 Dec 2020 at 10:46, Tomas Kalibera
>>> <tomas.kalibera using gmail.com <mailto:tomas.kalibera using gmail.com>>
>>> wrote:
>>>
>>> On 12/16/20 11:07 PM, joris using jorisgoosen.nl
>>> <mailto: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?
>
> Parsing for usual packages is done at build time, when they are
> serialized ("prepared for lazy loading"). I would have to look for
> the details in the code, but either way, if the input is in UTF-8
> but the native encoding is different, either the input has to be
> converted to native encoding for the parser, or that hack when
> part of the parser is being lied to about the encoding (either via
> "parse()" or other way). If you have a minimal reproducible
> example, I can help you find out whether the behavior seen is
> expected/documented/bug.
>
>> 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.
>
> Please look first at this part of "?parse":
>
> "encoding: encoding to be assumed for input strings. If the value
> is ‘"latin1"’ or ‘"UTF-8"’ it is used to mark character strings as
> known to be in Latin-1 or UTF-8: it is not used to re-encode the
> input. To do the latter, specify the encoding as part of the
> connection ‘con’ or _via_ ‘options(encoding=)’: see the example
> under ‘file’. Arguments ‘encoding = "latin1"’ and ‘encoding =
> "UTF-8"’ are ignored with a warning when running in a MBCS locale."
>
> Together with the one you cite:
>
> "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."
>
> There are two things: which encoding strings are really encoded
> in, and which encoding they are declared to be in. Normally this
> should always be the same encoding (UTF-8, latin-1, or the
> concrete known native encoding), but the "encoding=" argument
> allows to play with this. Strings declared to be in "native"
> encoding for a while are treated as (single-byte) unknown encoding
> and eventually they are declared to be of the encoding from the
> "encoding=" argument. This only applies to strings declared as
> "native". When strings are declared as UTF-8 or latin-1, they must
> be in that encoding, and believed to be in that, the "encoding="
> argument does not affect those.
>
> So, when your inputs are declared as UTF-8, the "encoding=" hack
> should not apply to them. Also note that ASCII strings are never
> declared to be UTF-8 nor latin-1, they are always as "native" (and
> ASCII is assumed a subset of all encodings). But your inputs
> probably are not declared to be in UTF-8 (note this is "declared"
> wrt to Encoding() R function, the encoding flag that character
> objects in R have), because you are probably parsing from a file.
> I'd really need a reproducible example to be able to explain what
> you are seeing.
>
> Best
> Tomas
>
>
>>> 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 <mailto: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
>>> <mailto:joris using jorisgoosen.nl>
>>> >> *Sent: *Wednesday, December 16, 2020 1:52 PM
>>> >> *To: *r-package-devel using r-project.org
>>> <mailto: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
>>> <mailto: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
>>> <mailto:R-package-devel using r-project.org> mailing list
>>> > https://stat.ethz.ch/mailman/listinfo/r-package-devel
>>>
>>>
>>
>
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