instead. This seems more robust than returning an Unicode string with
some unconverted charcters in it.
This still doesn't support getting truly binary data out of Tcl, since
we look for the trailing null byte; but the old (pre-Unicode) code did
this too, so apparently there's no need. (Plus, I really don't feel
like finding out how Tcl deals with this in each version.)
1. In Tcl 8.2 and later, use Tcl_NewUnicodeObj() when passing a Python
Unicode object rather than going through UTF-8. (This function
doesn't exist in Tcl 8.1, so there the original UTF-8 code is still
used; in Tcl 8.0 there is no support for Unicode.) This assumes that
Tcl_UniChar is the same thing as Py_UNICODE; a run-time error is
issued if this is not the case.
2. In Tcl 8.1 and later (i.e., whenever Tcl supports Unicode), when a
string returned from Tcl contains bytes with the top bit set, we
assume it is encoded in UTF-8, and decode it into a Unicode string
object.
Notes:
- Passing Unicode strings to Tcl 8.0 does not do the right thing; this
isn't worth fixing.
- When passing an 8-bit string to Tcl 8.1 or later that has bytes with
the top bit set, Tcl tries to interpret it as UTF-8; it seems to fall
back on Latin-1 for non-UTF-8 bytes. I'm not sure what to do about
this besides telling the user to disambiguate such strings by
converting them to Unicode (forcing the user to be explicit about the
encoding).
- Obviously it won't be possible to get binary data out of Tk this
way. Do we need that ability? How to do it?
For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.
(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode. I'm also holding back on his
change to main.c, which seems unnecessary to me.)
None in an argument list *terminates* the argument list: further
arguments are *ignored*. This isn't kosher, but too much code relies
on it, implicitly. For example, IDLE was pretty broken.
This was originally submitted by Martin von Loewis as part of his
Unicode patch; all I did was add special cases for Python int and
float objects and rearrange the object type tests somewhat to speed up
the common cases (string, int, float, tuple, unicode, object).
thread state of the thread calling mainloop() (or another event
handling function) rather than the thread state of the function that
created the client data structure.
low-level Python exit handler. This can attempt to call Python code
at a point that the interpreter and thread state have already been
destroyed, causing a Bus Error. Given the intended use of
Py_AtExit(), I'm not convinced that it's a good idea to call it
earlier during Python's finalization sequence... (Although this is
the only use for it in the entire distribution.)
PythonCmd_Error() but failed to return. The error wasn't very likely
(only when we run out of memory) but since the check is there we might
as well return the error. (I think that Barry introduced this buglet
when he added error checks everywhere.)
# from my PC at home, but it can't send email :-(
Add a clarifying comment about the new ENTER_OVERLAP and
LEAVE_OVERLAP_TCL macros; get rid of all the bogus tests for deleted
interpreters (Tcl already tests for this; they were left over from an
earlier misguided attempt to fix the threading).
There were some serious problem with the thread-safety code.
The basic problem was that often the result was gotten out of
the Tcl interpreter object after releasing the Tcl lock.
Of course, another thread might have changed the return value
already, and this was indeed happening. (Amazing what trying
it on a different thread implementation does!)
The solution is to grab the Python lock without releasing the
Tcl lock, so it's safe to create a string object or set the
exceptions from the Tcl interpreter. Once that's done, the
Tcl lock is released.
Note that it's now legal to acquire the Python lock while the
the Tcl lock is held; but the reverse is not true: the Python
lock must be released before the Tcl lock is acquired. This
in order to avoid deadlines. Fortunately, there don't seem to
be any problems with this.
(The "sort of" is because it uses kbhit() to detect that the user
starts typing, and then no events are processed until they hit
return.)
Also fixed a nasty locking bug: EventHook() is called without the Tcl
lock set, so it can't use the ENTER_PYTHON and LEAVE_PYTHON macros,
which manipulate both the Python and the Tcl lock. I now only acquire
and release the Python lock.
(Haven't tested this on Unix yet...)
Tkinter. This adds a separate lock -- read the comments. (This was
also needed for Mark Hammond's attempts to make PythonWin
Tkinter-friendly.)
The changes have affected the EventHook slightly, too; and I've done
some more cleanup of the code that deals with the different versions
of Tcl_CreateFileHandler().
registers an input file handler for stdin with Tcl and handles Tcl
events until something is available on stdin; it then deletes the
handler and returns from EventHook().
This works with or without GNU readline, and doesn't busy-wait.
It still doesn't work for Mac or Windows :-(
most common interface to Tcl, the call() method, by maybe 20-25%.
The speedup code avoids the construction of a Tcl command string from
the argument list -- the Tcl argument list is immediately parsed back
by Tcl_Eval() into a list that is *guaranteed* (by Tcl_Merge()) to be
exactly the same list, so instead we look up the command info and call
the command function directly. If the lookup fails, we fall back to
the old method (Tcl_Merge() + Tcl_Eval()) so we don't need to worry
about special cases like undefined commands or the occasional command
("after") that sets the info.proc pointer to NULL -- let TclEval()
deal with these.
the address of the Tcl interpreter object, as an integer. Not very
useful for the Python programmer, but this can be called by another C
extension that needs to make calls into the Tcl/Tk C API and needs to
get the address of the Tcl interpreter object. A simple cast of the
return value to (Tcl_Interp *) will do the trick now.
save and restore the tstate, but explicitly calling
PyEval_SaveThread() does reset it! While I think about how to fix
this for real, here's a fix that avoids getting a fatal error.
This one works! However it requires using a modified version of
tclNotify.c (provided), which requires access to the Tcl source
to compile it. In order to enable this hack, add the following
to the Setup line for _tkinter:
tclNotify.c -DHAVE_PYTCL_WAITUNTILEVENT -I$(TCL)/generic
where TCL points to the source tree of Tcl 8.0. Other versions
of Tcl are not supported.
The tclNotify.c file is copyrighted by Sun Microsystems; the
licensing terms are in the file license.terms. According to this
file, no further permission to distribute this is required,
provided the file license.terms is included. Hence, I am checking
that in, too.
Guido van Rossum