solver. In conjunction, they easily found a tour of a 200x200 board:
that's 200**2 == 40,000 levels of backtracking. Explicitly resumable
generators allow that to be coded as easily as a recursive solver (easier,
actually, because different levels can use level-customized algorithms
without pain), but without blowing the stack. Indeed, I've never written
an exhaustive Tour solver in any language before that can handle boards so
large ("exhaustive" == guaranteed to find a solution if one exists, as
opposed to probabilistic heuristic approaches; of course, the age of the
universe may be a blip in the time needed!).
We should not depend on two spaces between words, so use the white
space after the to-be-encoded word only as lookahead and don't
actually consume it in the regular expression.
path (with no profile/trace function) through eval_code2() and
eval_frame() avoids several checks.
In the common cases of calls, returns, and exception propogation,
eval_code2() and eval_frame() used to test two values in the
thread-state: the profiling function and the tracing function. With
this change, a flag is set in the thread-state if either of these is
active, allowing a single check to suffice when both are NULL. This
also simplifies the code needed when either function is in use but is
already active (to avoid profiling/tracing the profiler/tracer); the
flag is set to 0 when the profile/trace code is entered, allowing the
same check to suffice for "already in the tracer" for call/return/
exception events.
This allows system libs to be weak-linked, thereby allowing us to generate functions that are only available on some OS versions without getting a NULL dereference if the function isn't available.
- Convert CFString to/from Python strings. Currently always MacRoman, to be fixed later (as is unicode support). Python->CFString conversion is automatic.
committed.
tokenize.py: I like these changes, and have tested them extensively
without even realizing it, so I just updated the docstring and the docs.
tabnanny.py: Also liked this, but did a little code fiddling. I should
really rewrite this to *exploit* generators, but that's near the bottom
of my effort/benefit scale so doubt I'll get to it anytime soon (it
would be most useful as a non-trivial example of ideal use of generators;
but test_generators.py has already grown plenty of food-for-thought
examples).
inspect.py: I'm sure Ping intended for this to continue running even
under 1.5.2, so I reverted this to the last pre-gen-branch version. The
"bugfix" I checked in in-between was actually repairing a bug *introduced*
by the conversion to generators, so it's OK that the reverted version
doesn't reflect that checkin.
class FieldStorage: this patch changes read_lines() and co. to use a
StringIO() instead of a real file. The write() calls are redirected
to a private method that replaces it with a real, external file only
when it gets too big (> 1000 bytes).
This avoids problems in forms using the multipart/form-data encoding
with many fields. The original code created a temporary file for
*every* field (not just for file upload fields), thereby sometimes
exceeding the open file limit of some systems.
Note that the simpler solution "use a real file only for file uploads"
can't be used because the form field parser has no way to tell which
fields correspond to file uploads.
It's *possible* but extremely unlikely that this would break someone's
code; they would have to be stepping way outside the documented
interface for FieldStorage and use f.file.fileno(), or depend on
overriding make_file() to return a file-like object with additional
known properties.
examples of use. These poke stuff not specifically targeted before, incl.
recursive local generators relying on nested scopes, ditto but also
inside class methods and rebinding instance vars, and anonymous
partially-evaluated generators (the N-Queens solver creates a different
column-generator for each row -- AFAIK this is my invention, and it's
really pretty <wink>). No problems, not even a new leak.
"return expr" instances in generators (which latter may be generators
due to otherwise invisible "yield" stmts hiding in "if 0" blocks).
This was fun the first time, but this has gotten truly ugly now.
Python interpreter.
This change adds two new C-level APIs: PyEval_SetProfile() and
PyEval_SetTrace(). These can be used to install profile and trace
functions implemented in C, which can operate at much higher speeds
than Python-based functions. The overhead for calling a C-based
profile function is a very small fraction of a percent of the overhead
involved in calling a Python-based function.
The machinery required to call a Python-based profile or trace
function been moved to sysmodule.c, where sys.setprofile() and
sys.setprofile() simply become users of the new interface.
As a side effect, SF bug #436058 is fixed; there is no longer a
_PyTrace_Init() function to declare.
Python interpreter.
This change adds two new C-level APIs: PyEval_SetProfile() and
PyEval_SetTrace(). These can be used to install profile and trace
functions implemented in C, which can operate at much higher speeds
than Python-based functions. The overhead for calling a C-based
profile function is a very small fraction of a percent of the overhead
involved in calling a Python-based function.
The machinery required to call a Python-based profile or trace
function been moved to sysmodule.c, where sys.setprofile() and
sys.setprofile() simply become users of the new interface.
unknown
Fred Drake
Kurt B. Kaiser
Fredrik Lundh
Jack Jansen
Tim Peters
Guido van Rossum
Andrew M. Kuchling
Martin v. Löwis
Barry Warsaw