Re: [Python-Dev] Negative timedelta strings
n 31.03.2014 21:09, Chris Barker wrote: On Fri, Mar 28, 2014 at 2:52 PM, Fred Drake f...@fdrake.net wrote: On Fri, Mar 28, 2014 at 5:19 PM, Greg Ewing greg.ew...@canterbury.ac.nz wrote: ISO 8601 doesn't seem to define a representation for negative durations, though, so it wouldn't solve the original problem. Aside from the horribleness of the ISO 8601 notation for a duration, it's best not to confuse the notions of duration and delta. Notionally, a delta contains more information than a duration. and less -- really it's different. A duration would be really useful actually, for things like next month, etc,. IIRC, mxDateTime has something for this, but it's NOT the same as a timedelta. mxDateTime has DateTimeDelta objects which represent a time delta (in the mathematical sense) between two points in DateTime and RelativeDateTime objects which allow defining deltas in terms of qualifiers which are applied to the left hand side of an operation. With RelativeDateTime you can do things like e.g. first_of_next_month = now() + RelativeDateTime(months=+1, day=1) There are some other concepts you can emulate with these, like e.g. a specific time frame (DateTime + one of the above deltas), a reoccurring time (start_time + one of the deltas + number occurrences + exceptions), an age concept (difference between two DateTime values expressed in RelativeDateTime terms), etc. Some examples: from mx.DateTime import * print RelativeDateTime(months=+1, day=1) -(+01)-01 HH:MM:SS print now() + RelativeDateTime(months=+1, day=1) 2014-05-01 14:49:05.83 print Age(now(), Date(1969,4,6)) (+0044)-(+11)-(+27) (+14):(+49):(+02) -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Apr 02 2014) Python Projects, Consulting and Support ... http://www.egenix.com/ mxODBC.Zope/Plone.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ 2014-04-09: PyCon 2014, Montreal, Canada ...7 days to go 2014-04-29: Python Meeting Duesseldorf ... 27 days to go : Try our mxODBC.Connect Python Database Interface for free ! :: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Negative timedelta strings
On Wed, Apr 2, 2014 at 7:52 AM, M.-A. Lemburg m...@egenix.com wrote: print now() + RelativeDateTime(months=+1, day=1) 2014-05-01 14:49:05.83 I find this sort date arithmetic unintuitive, though I'm at a loss to come up with better logic than you have: d = Date(2014, 2, 28) d + RelativeDateTime(months=+1) mx.DateTime.DateTime object for '2014-03-28 00:00:00.00' at 1eda8c8 d = Date(2014, 1, 31) d + RelativeDateTime(months=+1) mx.DateTime.DateTime object for '2014-03-03 00:00:00.00' at 1eda870 I guess the assumption is that one month is the length in days of the current month, though, you wind up with situations where shorter months can be skipped altogether. Is there a way to talk in terms of months but not have short months get skipped? Thx, Skip ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Negative timedelta strings
On 2014-04-02, at 15:04 , Skip Montanaro s...@pobox.com wrote: On Wed, Apr 2, 2014 at 7:52 AM, M.-A. Lemburg m...@egenix.com wrote: print now() + RelativeDateTime(months=+1, day=1) 2014-05-01 14:49:05.83 I find this sort date arithmetic unintuitive, though I'm at a loss to come up with better logic than you have: d = Date(2014, 2, 28) d + RelativeDateTime(months=+1) mx.DateTime.DateTime object for '2014-03-28 00:00:00.00' at 1eda8c8 d = Date(2014, 1, 31) d + RelativeDateTime(months=+1) mx.DateTime.DateTime object for '2014-03-03 00:00:00.00' at 1eda870 I guess the assumption is that one month is the length in days of the current month, though, you wind up with situations where shorter months can be skipped altogether. Is there a way to talk in terms of months but not have short months get skipped? FWIW dateutil has a slightly different logic there: date(2014, 2, 28) + relativedelta(months=+1) datetime.date(2014, 3, 28) date(2014, 1, 31) + relativedelta(months=+1) datetime.date(2014, 2, 28) ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Negative timedelta strings
On 02.04.2014 15:04, Skip Montanaro wrote: On Wed, Apr 2, 2014 at 7:52 AM, M.-A. Lemburg m...@egenix.com wrote: print now() + RelativeDateTime(months=+1, day=1) 2014-05-01 14:49:05.83 I find this sort date arithmetic unintuitive, though I'm at a loss to come up with better logic than you have: d = Date(2014, 2, 28) d + RelativeDateTime(months=+1) mx.DateTime.DateTime object for '2014-03-28 00:00:00.00' at 1eda8c8 d = Date(2014, 1, 31) d + RelativeDateTime(months=+1) mx.DateTime.DateTime object for '2014-03-03 00:00:00.00' at 1eda870 I guess the assumption is that one month is the length in days of the current month, though, you wind up with situations where shorter months can be skipped altogether. Is there a way to talk in terms of months but not have short months get skipped? I'm not really satisfied with this solution either. The problem is that the qualifier + 1 month is not defined for dates with don't have a corresponding day in the following month. This should probably either raise an exception or use some parameter to solve the problem, by e.g. choosing the last day of the month or using the current scheme: mxDateTime skips to the first of the next month and then advances the number of days defined in the left hand DateTime value, i.e. Date(2014, 2, 1) + 30 * oneDay. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Apr 02 2014) Python Projects, Consulting and Support ... http://www.egenix.com/ mxODBC.Zope/Plone.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ 2014-04-09: PyCon 2014, Montreal, Canada ...7 days to go 2014-04-29: Python Meeting Duesseldorf ... 27 days to go : Try our mxODBC.Connect Python Database Interface for free ! :: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] libpython added to ABI tracker
Nick Coghlan wrote:
Regarding the warnings for this one - is there a way for the checker
to warn if data structures are exposed directly, rather than as opaque
types? It's fine if there isn't, it would just be cool if there was -
one of the premises of the stable ABI is that it *doesn't* expose the
type definitions directly to consuming code, just the pointers to them
(hence allowing the struct size to change without actually breaking
compatibility with the defined ABI).
The ABI of the library can be dumped by the abi-compliance-checker basic
tool to a text file in the human readable format, so anyone can analyse
it in order to find problems of any kind.
Homepage of the tool: https://github.com/lvc/abi-compliance-checker
To dump the libpython ABI type:
$ abi-compliance-checker -l libpython -dump descriptor.xml
The descriptor.xml input file ({RELPATH} - path to the python install
tree, i.e. installation prefix):
version
3.4.0
/version
headers
{RELPATH}/include
/headers
libs
{RELPATH}/lib/libpython3.4m.so.1.0
/libs
skip_including
ast.h
Python-ast.h
asdl.h
pyexpat.h
pymactoolbox.h
/skip_including
gcc_options
-DPy_LIMITED_API=0x0302
/gcc_options
I've already created the sample dump of the libpython-3.4.0 stable ABI
here: http://upstream-tracker.org/downloads/libpython_3.4.0.abi.tar.gz
In order to analyse data types in the ABI please read 'TypeInfo' section
of the dump.
I see several structures with exposed definition in the stable ABI v3.4.0:
struct PyStructSequence_Desc
struct grammar
struct PyStructSequence_Field
struct _node
struct cchar_t
struct PyType_Spec
struct PyType_Slot
struct dfa
struct labellist
struct PyMethodDef
struct _Py_Identifier
struct state
struct PyVarObject
struct arc
struct label
struct PyModuleDef
struct PyModuleDef_Base
struct PyMemberDef
struct PyGetSetDef
struct _object
struct PyCursesWindowObject
Thanks.
--
Andrey Ponomarenko, NTC IT ROSA.
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Re: [Python-Dev] libpython added to ABI tracker
Am 01.04.14 13:45, schrieb Nick Coghlan: Interesting to see the UCS2 removal there for 3.3. That's a genuine removal from the public ABI as part of PEP 393. I guess the reason nobody complained is because most 3.2 Linux builds used the UCS4 ABI instead, and the stable ABI hadn't seen broad adoption on Windows in the 3.2-3.3 time frame. Not really. The intention was that the stable ABI wouldn't have any UCS2/UCS4 denotation in the function names, see http://hg.python.org/cpython/file/9186f4a18584/PC/python3.def Functions that explicitly referred to Py_UNICODE were banned from the ABI; functions that were mapped but shouldn't have been mapped were meant to be unmapped. However, it seems that this wasn't properly implemented, see http://bugs.python.org/issue17432 Regardless, this service already shows we've made some mistakes with the stable ABI in previous releases - it is indicating there are new symbols in the stable ABI for 3.3 and 3.4 that aren't properly guarded with version constraints. That means it is currently possible to set Py_LIMITED_API=0x0302 and get something that won't actually run properly on 3.2. Depends on the operating system. On Windows, the import library has much less additions; anything declared in the header files that is not in python3.def is a bug in the header files (by default). Regards, Martin ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] Gmane not functioning.
Just to let those who read the list as a list (or via mail.python.org, as I just did as a backup) know, news.gmane.org appears to have stoppedreceiving new messages from mailing listsat about 0:30 this morning (apr 2). (I am judging this from the last recorded post on the super-busy linux kernallist http://news.gmane.org/gmane.linux.kernel/cutoff=1676398). So there will be some unknown number of people not reading and posting who might otherwise. Ditto for other lists. -- Terry Jan Reedy ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
