Tcl has two options to do what you suggest:
- Set the system encoding to cp1252
- Source the file using -encoding cp1252
(A third is to adapt the C side of the Plplot API.)
I will experiment with both.
On 2010-12-24 22:20, Alan W. Irwin wrote:
> On 2010-12-24 13:05+0100 Arjen Markus wrote:
>> Hi Alan,
>> On 2010-12-21 20:03, Alan W. Irwin wrote:
>>> I will stop now and not comment more on the Tcl case, because I think
>>> it is essential to focus on C for now and one of the cairo or qt
>>> Of course, as I have stated before the psc device driver is not useful
>>> for diagnosis of encoding issues because everything exotic such as the
>>> Mandarin Peace word ends up as blanks in any case because the standard
>>> Type 1 fonts that the psc device uses have an extremely limited glyph
>>> set that does not include Mandarin glyphs or any other non-English
>>> glyphs besides Greek (for mathematical purposes).
>> I have checked the C and F95 examples 24 with the wxWidgets device on
>> Windows: they work very nicely, except that my PC does not have all the
>> required fonts. With Tcl I recognise the odd sequences I also see in
>> the source code (viewed from a cp1252 perspective).
> Thus, it appears from your results that C and Fortran on Windows
> simply accept the byte sequences mentioned in strings without
> molesting them while your hypothesis is that Tcl does not follow that
> simple model. Instead it does an implicit transformation of all
> strings from (presumed) system encoding to UTF-8 which messes up the
> byte sequences, and your proposed cure is to take all strings input to
> PLplot from Tcl and do the inverse transformation which uses
> a call to Tcl_UtfToExternalDString with a
> NULL encoding. From the man page, what that will do is to convert a
> (presumed) UTF-8 string to the (presumed) system encoding.
> If your hypothesis is correct, then your proposed cure might indeed
> work on all platforms. Certainly on Linux, the implicit
> transformation is UTF-8 to UTF-8 or the identity transform (which is
> why Tcl works right now for example 24 on Linux), and your inverse
> transformation would also be the identify transformation on Linux and
> should therefore also work on that platform.
> However, I am concerned with the following issues.
> 1. All PLplot API arguments that are strings are assumed to be in
> UTF-8. Thus, the call to Tcl_UtfToExternalDString with NULL has to be
> made in the Tcl bindings for _every_ function in the PLplot API that
> has an input string.
> 2. Does the implicit transformation work for arbitrary UTF-8 (e.g.,
> arbitrary series of 8-bit bytes) or are there some 8-bit bytes which
> cannot be validly interpreted as cp1252 or which have special
> 3. Is Tcl_UtfToExternalDString with NULL encoding the exact inverse
> of the implicit transformation?
> All of these issues can be dealt with. Obviously some care in the Tcl
> bindings should take care of issue 1 and to alleviate concern about
> issues 2 and 3 completely, it would be a good idea to put together a
> complete test of all 256 possible 8-bit character combinations. I am
> thinking along the lines of generating a file from C with a string of
> all possibilities from 255 down to a zero (to terminate the string).
> Then using an editor copy that exact string of 256 bytes to Tcl source
> code that automatically puts that string through the implicit
> transformation. Then use the Tcl_UtfToExternalDString with NULL to
> transform that string before calling a C programme that simply outputs
> the string. Then compare that output file with the original file with
> 256 characters to see if you get all 256 characters back in their
> original form.
> However, to avoid this work it would be better to convince Tcl not to
> do the implicit string transformation in the first place. The way
> this is handled in Python is to put the following string in the
> first or second line of the Python script that identifies the
> whole Python source file is encoded in utf-8:
> # -*- coding: utf-8 -*-
> We do that for the following Python examples:
> software@...> grep coding: examples/python/xw??.py
> examples/python/xw18.py:# -*- coding: utf-8; -*-
> examples/python/xw24.py:# -*- coding: utf-8; -*-
> examples/python/xw26.py:# -*- coding: utf-8; -*-
> examples/python/xw33.py:# -*- coding: utf-8; -*-
> I think Tcl may have something equivalent in the
> encoding system utf-8
> command. From the documentation users are discouraged from using that
> command because it affects everything such as system calls. For
> example, puts would output strings in UTF-8 encoding rather than the
> actual (e.g., cp1252 on your platform) system encoding on Windows
> machines. But is that actually an issue for the above examples?
> First, we don't interact with the operating system (e.g, with puts) as
> far as I know with those examples, and UTF-8 and cp1252 coincide in
> any case for ascii strings. Anyhow, if "encoding system utf-8" works
> for those examples, I think we should use it rather than the more
> difficult steps outlined above. Of course, we should inform Tcl users
> browsing our example code via a comment in those examples that PLplot
> requires utf-8 system encoding for all non-ascii input strings.
>> Over the weekend I won't be able to do anything - holiday
>> obligations :).
>> I wish you all a merry Christmas and a happy New Year.
> I wish everybody here a "Merry Christmas" and "Happy New Year" as well.
> Enjoy your holidays, Arjen, and I hope when you come back you will
> find the "encoding system utf-8" solution works without issues for the
> affected examples.
> Alan W. Irwin
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
> Programming affiliations with the FreeEOS equation-of-state implementation
> for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
> package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
> Linux Links project (loll.sf.net); and the Linux Brochure Project
> Linux-powered Science
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