Update of bug #64484 (group groff):
Status: Postponed => In Progress
Summary: [troff] \X escape sequence should read its argument
in (something like) copy mode => [troff] .device and \X should behave
similarly
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Follow-up Comment #21:
Restoring original summary, more or less, and un-postponing.
1. \X should encode special characters in its argument in `\[uXXXX]` form.
This is done.
2. The `device` request should do the same.
3. Neither `\X` or `device` should cause a blanket flush of 5 different
things:
set_font(tf);
glyph_color(gcol);
fill_color(fcol);
flush_tbuf();
do_motion();
Right now they both do, and this causes documents to regress. People have
undertaken baffling workarounds like:
. nop \!x X ps:exec [/Dest /\\*[PDFBOOKMARK.NAME] /Title (\\*[pdf:title])
/Level \\n[pdf:bm.lev] /OUT pdfmark
...which really should be expressible as:
. device ps:exec [/Dest /\\*[PDFBOOKMARK.NAME] /Title (\\*[pdf:title])
/Level \\n[pdf:bm.lev] /OUT pdfmark
(That's from "pdf.tmac"'s `pdfbookmark` macro definition, which is why the
backslashes are doubled.)
Extend the `fl` request to take letter arguments encoding which bits of state
should marked dirty, or flushed, depending on how you look at it.
f set_font()
m glyph_color()
M fill_color()
t flush_tbuf()
p do_motion()
These aren't the world's best mnemonics. Lots of collisions here:
font/fill/flush, m/M/motion. But we need _something_.
Maybe we can read an "identifier" (word) at a time and `strcmp()` it. That'd
be less gross.
Most device extension commands won't need to perform a flush, because they
don't dirty any of these states. sboxes is an exception. But all it needs to
dirty is the fill color (and _maybe_ the glyph color, because of the box
edges?)...but not the rest. `do_motion()` in particular appears to cause
grief, and breaks Peter's _mom_ documents, unaligning the shaded boxes with
the text that's supposed to be in them.
Possibly once all this is done we won't need the long-undocumented `tag` and
`taga` ("tag append") requests anymore. I get the feeling they were stuck in
to avoid the state-flushing problems described above. One bit I don't
understand is what's being "appended": both write out "x X" commands,
seemingly right away. `taga` has very limited use: one invocation in
"devtag.tmac", which calls it from one macro "DEVTAG-NEXT", which itself has
only one caller anywhere, "DEVTAG-COL-NEXT". _me_ and _ms_ (and only those)
call that, but I don't know if columnated HTML output works with those
packages in the first place. Find out. If it doesn't, nothing is lost if we
"break" it.
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