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[Stephen Lyons <1397594@xxxxxxxxxxxxxxxxxx>]

N.B. the above file is NOT entirely viewable directly in your browser
(at least not one that validates XML) it will error out at the offending
escape character...!

The problem, as Vadim and I now know it is that the XML 1.0
specification PROHIBITS the use of the ASCII "C0" group of control
characters (with single byte values between 0x01 and 0x1F) EXCEPT for
the Tab, Line-Feed and Carriage Return ones {0x09,0x0A & 0x0D}.  This
design restriction has been reversed in XML 1.1 however such codes must
be entered as "numeric entities" i.e. for the above escape in the form
"" or "" there.  That doesn't help us though, because Qt does
not support XML 1.1 (the documentation for QXmlStreamReader and
QXmlStreamWriter is not immediately clear unless you look at the small
print - despite the apparent ability to change the ability to change the
XML version text on the first line of the file that the writer produces
that does not alter the fact that the reader does say that it is a 1.0
reader - the 1.1 {now on it's third revision I believe} specification
has been around since 2006 so it is not as if it is THAT new fangled.)

One partial solution which I want to check further is to use custom
entities for those control characters until Qt does parse 1.1 type
documents.  The attached file uses an entity (which comprises a leading
'&' the TLA "esc" and the trailing ';' character.  For display purposes
that (and all the other C0 control characters) entities have replacement
characters in the Unicode range {U+2400 to U+241F} that are pictorial
representations of the C0 characters - unfortunately the Deja Vu series
of fonts that we include with Mudlet do not include those glyphs and the
free Symbola font that I want to include in future Mudlet version (for a
very extensive range of Map symbols) uses glyphs that look a lot like
the IBM PC ROM ones that computer users from the MSDos 3.3-6.0 era might
recognize - the visual effect I was hoping for is realizable using the
FSF's GPLv3 FreeFonts (FreeSerif, FreeSans, FreeMono) or RedHat's GPLv2
Liberation font set (Liberation[-]Mono, [-]Sans, [-]Sans Narrow,
[-]Serif) though others will do.

That only covers however the part about having a file that a browser and
a human read can read.  It means that, provided a suitable font is
available on the system the C0 characters will be displayable in their
Unicode form.  What is left is that we will also need to hack the editor
for the simple "command to send" type QLineEdits and the "script" multi-
line edit boxes so that they "store" and "edit" the
"&<2or3LetterAcronyms>;" form - but these will need to be "translated"
at the point that any such codes get sent to the MUD server OR if also
permitted in other places where the user want them to match MUD server
output {perhaps custom telnet sub command handling code?}

At the point we implement this I'd up the Mudlet package version to 1.1
(like I have in the attached sample) and start to process the file in
this new way - so that if Qt gains XML 1.1 support not only will the
first line change but we can increment our package form to 1.2 because I
think THEN we'd want to change the entity definitions at start of the
file to put in the permitted numeric C0 codes directly...

tl;dr;

Anyhow I know that I must do some more research before I could compose a
complete solution...

** Attachment added: "Possible new format sample XML file"
   https://bugs.launchpad.net/mudlet/+bug/1397594/+attachment/4273297/+files/test_entity.xml

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https://bugs.launchpad.net/bugs/1397594

Title:
  XML importer stops importing on the escape character

Status in Mudlet the MUD client:
  Confirmed

Bug description:
  The XML importer (for importing packages or loading profiles) chokes
  on the escape character (0x1B) and does not load anything after, thus
  corrupting scripts that include it.

  Attached is a test alias that demonstrates the problem.

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