Programs that want to background themselves now need
to define threadmaybackground returning 1.
This avoids a confusing (to people and debuggers)
extra parent process for all the threaded programs
that will never want to background themselves.
Drawing as white on black to produce a mask only works if
the white on black is the inversion of black on white.
Emoji that force use of specific colors don't respect that.
Draw black on white and invert to mask separately.
This fixes https://github.com/9fans/plan9port/issues/436
This doesn't necessarily address the underlying issue: calling p9create with
mode = OREAD should probably be allowed, but currently doesn't work on
OpenBSD.
Unclear why it is here (wkj added it long ago).
It has never been installed into $PLAN9/bin,
so it's doubtful that anyone has ever used it.
Arnold Robbins has an alternate version at
https://github.com/arnoldrobbins/dformat.
Fixes#421.
List mode was constrained to the BMP. This change introduces
the following new list mode convention, using Go string literal syntax:
Non-printing ASCII characters display as \xhh.
Non-ASCII characters in the BMP display as \uhhhh.
Characters beyond the BMP display as \Uhhhhhhhh.
Runes in Plan 9 were limited to the 16-bit BMP when I drew up
the RPC protocol between graphical programs and devdraw
a long time ago. Now that they can be 32-bit, use a 32-bit wire
encoding too. A new message number to avoid problems with
other clients (like 9fans.net/go).
Add keyboard shortcut alt : , for U+1F602, face with tears of joy,
to test that it all works.
This fixes at least one shell script (printfont) that expected
'x'`{y}'z'
to mean
'x'^`{y}^'z'
as it now does. Before it meant:
'x'^`{y} 'z'
One surprise is that adjacent lists get a free carat:
(x y z)(1 2 3)
is
(x1 y2 z3)
This doesn't affect any rc script in Plan 9 or plan9port.
The old yacc-based parser is available with the -Y flag,
which will probably be removed at some point.
The new -D flag dumps a parse tree of the input,
without executing it. This allows comparing the output
of rc -D and rc -DY on different scripts to see that the
two parsers behave the same.
The rc paper ends by saying:
It is remarkable that in the four most recent editions of the UNIX
system programmer’s manual the Bourne shell grammar described in the
manual page does not admit the command who|wc. This is surely an
oversight, but it suggests something darker: nobody really knows what
the Bourne shell’s grammar is. Even examination of the source code is
little help. The parser is implemented by recursive descent, but the
routines corresponding to the syntactic categories all have a flag
argument that subtly changes their operation depending on the context.
Rc’s parser is implemented using yacc, so I can say precisely what the
grammar is.
The new recursive descent parser here has no such flags.
It is a straightforward translation of the yacc.
The new parser will make it easier to handle free carats
in more generality as well as potentially allow the use of
unquoted = as a word character.
Going through this exercise has highlighted a few
dark corners here as well. For example, I was surprised to
find that
x >f | y
>f x | y
are different commands (the latter redirects y's output).
It is similarly surprising that
a=b x | y
sets a during the execution of y.
It is also a bit counter-intuitive
x | y | z
x | if(c) y | z
are not both 3-phase pipelines.
These are certainly not things we should change, but they
are not entirely obvious from the man page description,
undercutting the quoted claim a bit.
On the other hand, who | wc is clearly accepted by the grammar
in the manual page, and the new parser still handles that test case.
The issue manifests in fork: POSIX fork mandates that a
fork'd process is created with a single thread. If a
multithreaded program forks, and some thread was in
malloc() when the fork() happened, then in the child
the lock will be held but there will be no thread to
release it.
We assume the system malloc() must already know how to
deal with this and is thread-safe, but it won't know about
our custom spinlock. Judging that this is no longer
necessary (the lock code was added 15 years ago) we remove
it.
Signed-off-by: Dan Cross <cross@gajendra.net>
