ANN: cElementTree 1.0.4 (december 13, 2005)
effbot.org proudly presents release 1.0.4 of the cElementTree library, a fast and very efficient implementation of the ElementTree API, for Python 2.1 and later. On typical documents, it's 15-20 times faster than the Python version of ElementTree, and uses 2-5 times less memory. cElementTree 1.0.4 is 1.0.2 plus 2.3.5/2.4.2 compatibility fixes for copy/deepcopy (previously released as 1.0.3, as binaries only), new pi and comment targets in XMLParser, plus the ability to link against pyexpat instead of expat (this requires Python 2.5). The library is available as C source code, and as Windows installers for recent Python versions. Get your copy here: http://effbot.org/downloads#celementtree The cElementTree module uses some support functions from the standard ElementTree library, and will not work properly without it. If you haven't installed it already, you can get it from: http://effbot.org/downloads#elementtree enjoy /F -- http://mail.python.org/mailman/listinfo/python-announce-list Support the Python Software Foundation: http://www.python.org/psf/donations.html
Re: Adding methods to instances
Op 2005-12-15, Ed Leafe schreef [EMAIL PROTECTED]: On Dec 15, 2005, at 11:51 AM, Lawrence Oluyede wrote: So? Am I nuts? Or is this possible? Yes it is, use exec() to turn your string in valid Python code and bind the dynamic function as a method of class Test xx = def dynamic(self): print dynamic, self.testAtt exec xx class Test(object): testAtt = sample def normalMethod(self): print normal, self.testAtt t = Test() Test.dynamic = dynamic t.dynamic() Thanks! I knew I had done this before. My mistake was that I was setting the exec'd code to the instance, and not to the class. That works, but makes it a function, which doesn't automatically get sent the 'self' reference. But this will make the function a method to all instances of the class. Is that what you want? From your first post I had the impression you only wanted the function to be the method of one particular instance. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: special operator =+
Peter Hansen wrote: [EMAIL PROTECTED] wrote: kenny NguyenDoes anyone know the operator =+? It isn't an operator, it's equivalent to = (assignment) only. Though actually it would try to call the __pos__ method on the object prior to binding it to the name on the left side. (Much as - would call the __neg__ method if it existed.) :-) Technically one shouldn't really say it, since the sequence can only occur in an assignment or a keyword argument specification, and in all cases it's actually two symbols, an = followed by a unary + operator. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC www.holdenweb.com PyCon TX 2006 www.python.org/pycon/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python24.dll and encodings ?
Bugs [EMAIL PROTECTED] writes: Thomas Heller wrote: [snip] A PEP discussing the rationales would *really* be great. My whole impetus for this thread was to minimize the size of Python executables created with py2exe. Right now they tend to be rather large, even for very small applications, as they include a bunch of unutilized Python functionality and/or encodings. That was what I guessed. It would be nice to see a Python environment structure that is more desktop-application-friendly for applications that distribute the Python environment WITH the application (i.e. using py2exe). Ideally, it would be nice to be able to distribute as minimal amount of the Python runtime environment as possible. Before py2exe had the single-file option, the most common 'complaint' was the large number of files it generated. Now, the 'complaint' is about the size of the executable. (Historically, the change in Python2.4 was done by Martin on my request, that was before the single-file option in py2exe. Plus, Python2.4 contains much more encodings than 2.3 had.) The PEP would probably have to find a balance between the number of files and the size of a 'typical' py2exe built application. Personally, I don't care too much on either the file number and the files sizes since I use inno setup for distributing the applications. Technically, as far as py2exe is concerned, it would be nice if the zlib module was a builtin module because it would be easier to bootstrap the executable - for obvious reasons the zlib module cannot be loaded from a (compressed) zipfile. Unfortunately, this collides with Martin's current policy to exclude extensions that need third party source code from the python dll. To summarize: Before someone requests a change to the builtin modules list, a PEP would be needed to find the right balance. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: problem with os.spawnle(os.P_NOWAIT,'C:\info.exe')
[EMAIL PROTECTED] write; i tried running a exe file info.exe from the spawnle cmd, its running fine from the interactive mode, but when i try to run the same info.exe file from a python file, its giving me the following error: ## Traceback (most recent call last): File C:\Documents and Settings\shivayogimath_dc\Desktop\network.py, line 56, in ? os.spawnle(os.P_NOWAIT,'C:\info.exe') File C:\Python23\Lib\site-packages\wmi.py, line 263, in __getattr__ raise AttributeError, attribute AttributeError: spawnle Could u please help in removing this error. if os.spawnle gives you an attribute error in a module that's installed under site-packages, it's likely that you've overwritten the name os in your code. as an emergeny fix, add import os to the line just before os.spawnle. (if you're lucky, this will break the code that overwrote the os name, so you can fix that...) /F -- http://mail.python.org/mailman/listinfo/python-list
Re: IsString
Steven D'Aprano wrote: On Thu, 15 Dec 2005 08:22:37 +, Steve Holden wrote: Hear, hear. However you describe it Python is what it is, and this interminable discussion about its similarities with and differences from various concepts (most lately call by name/call by value) doesn't much aid understanding for the majority. The important question is not what's that Python concept called in other languages but do you understand how Python works. Would you have a problem with me describing Python as an untyped high-level assembly-language, and then working around the lack of JMP using try...exempt? Of course, I understand that it is no skin off your nose whether I write bad code or not, but you might get mighty frustrated with my constant questions on the news group How do I write this piece of assembly code in Python?. I was merely trying to imply that this particular piece of interpreter-navel-gazing has gone on way too long to sustain most readers' interest. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC www.holdenweb.com PyCon TX 2006 www.python.org/pycon/ -- http://mail.python.org/mailman/listinfo/python-list
RE: Tuples
Well, it works for me and x is a list, not a tuple. Or am I reading too much into your subject line? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] n.org]On Behalf Of Tuvas Sent: Thursday, December 15, 2005 12:20 PM To: python-list@python.org Subject: Tuples Let's say I make a program something like follows: x=[] x.append([1,2,3]) x.append([4,5,6]) print x print x[0] print x[0][1] x[0][1]=5 Okay, everything works here as expected except the last line. Why won't this work? Thanks for the help! The information contained in this message and any attachment may be proprietary, confidential, and privileged or subject to the work product doctrine and thus protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me immediately by replying to this message and deleting it and all copies and backups thereof. Thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: The difference between import package.module and from package import module(about pymol)
Xiao Jianfeng [EMAIL PROTECTED] writes: In pymol I can use from chempy import Atom but import chempy.Atom doesn't work. It says,ImportError: No module named Atom. What is going wrong ? I would trust the error message first, and check your assumption. Is 'chempy' actually a package, containing an 'Atom' module? Or is 'chempy' actually a module, containing an 'Atom' attribute? -- \I washed a sock. Then I put it in the dryer. When I took it | `\ out, it was gone. -- Steven Wright | _o__) | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: ActivePython and Amara
Where I go to work, a quote stands etched in a very large font into the concrete prominently to remind us to be humble. The greatest obstacle to discovery is not ignorance - it is the illusion of knowledge. (Daniel J. Boorstin) You just have to trust us on this. We are not jumping to conclusions based on one or two silly posts. It was evident in almost *every* post you posted so far. *You really are a newbie* and there is nothing wrong with that. We all have been there. But you must stop being defensive about it. You just need to be patient and read all the docs before trying to do what you are trying to do now. Here is a link to keep you busy. http://www.awaretek.com/tutorials.html -- http://mail.python.org/mailman/listinfo/python-list
Re: How can I load python script into Html ??
Steve M [EMAIL PROTECTED] wrote: Man, I don't even know where to start. There is no way this will work if you don't have a web browser that can interpret Python. I don't know of one, and I don't think anybody wants one because using a browser that would execute arbitrary Python code provided by the server would be an obscene security mistake. Internet Explorer will happily do so, if you have the Python Windows extensions installed, and register the active scripting component that cmes with it. -- - Tim Roberts, [EMAIL PROTECTED] Providenza Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
Re: getsockopt
Fabian Deutsch wrote:
Hello,
my name is fabian and i'm a student from northern germany. right now i
try to create som kind of decapsulation of esp-udp packets using python.
therefor i need to use the socket.getsockopt (SOL_IP, IP_OPTIONS, 20)
method. But al i get is some empty value. Nothin.
Does someone know or have an working exmaple of how to use this method??
The lines:
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)
s.bind(('',4500))
while 1:# Run until cancelled
message, client = s.recvfrom(1400) # =256 byte datagram
hdr = s.getsockopt (SOL_IP, IP_OPTIONS, 20)
print Client connected:, client
print HDR: + binascii.hexlify(hdr)
Perhaps you're getting an empty string back because no IP options are
set in the received packets' headers?
regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.python.org/pycon/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Op 2005-12-16, Ben Finney schreef [EMAIL PROTECTED]:
[quoting private email with permission]
Antoon Pardon wrote:
I just downloaded your enum module for python [from the Cheeseshop]
and played a bit with it. IMO some of the behaviour makes it less
usefull.
Feedback is appreciated. I'm hoping to provide a one obvious way to
do enumerations in Python.
from enum import Enum
day = Enum('mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun')
col = Enum('red', 'green', 'blue')
day.wed == col.blue
Traceback (most recent call last):
File stdin, line 1, in ?
File enum.py, line 100, in __cmp__
raise EnumValueCompareError(self, other)
enum.EnumValueCompareError: Not values from the same enumeration:
(EnumValue(enum.Enum object at 0x4020c30c, 2, 'wed'),
EnumValue(enum.Enum object at 0x4021a14c, 2, 'blue'))
type(day.mon) == type(col.red)
True
type(day.mon) is type(col.red)
True
lst= [day.mon, col.red]
day.fri in lst
As can be seen from the above, you raise an exception when one wants
to compare Enums from different enumarations, but it seems a bit
strange that different enumerations belong to the same type.
This does seem a point that could be confusing. Would it be better if
every Enum instance had its own unique subclass of EnumValue, that was
used to instantiate values for that enumeration?
If you decide on keeping the current behaviour when comparing
values of different enumerations, I would definitely answer
yes.
I also think it would be more usefull if enums from different
enumerations just tested unequal.
My rationale for this is: The only purpose of an enumeration is to
have a set of arbitrary unique values within that enumeration. The
values make no sense in the context of a different enumeration, so I
see three different comparison results:
Weekday.mon == Weekday.mon
True
Weekday.fri == Weekday.mon
False
Colour.blue == Weekday.mon
[...]
enum.EnumValueCompareError: Not values from the same enumeration
However, I'm aware that this is not how other Python types behave:
23 == 23
True
42 == 23
False
spam == 23
False
Is there a semantic difference between these cases? Is that difference
enough to want different behaviour?
Is there some behaviour other than evaluate to False or raise an
exception, that could indicate not comparable?
This is a difficult question, because AFAIU python doesn't have clear
guidelines for this. I also have the impression that comparisons are
used for two different reasons.
The first is compare things in a mathematical kind of way in which
how things are compared is important.
The second is more an ordering mechanisme. Whether a string is greater
than an int or vice versa, is not imporant what is important is that
this order is consistent and can be used in binary searches, trees
and other structures to organise data.
Now python has only one collection of compare operators which can
cause conflicts. For instance, one could impose an order on sets
to use for such structure but that goes against the normal order
on sets which is based on subsets.
The only advise I have here is look at PEP 3000 that states:
Comparisons other than == and != between disparate types will raise
an exception unless explicitly supported by the type.
Which seem to imply that == and != should not raise an exception
but , =, , = should.
--
Antoon Pardon
--
http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Mike Meyer [EMAIL PROTECTED] writes:
Peter Hansen [EMAIL PROTECTED] writes:
That is, [perhaps] trying to compare enumerations that should not
be compared *is* an error (raising an exception) *because* the
whole point of enumerations is to avoid errors in such cases.
Except it might not be an error. For instance, if I've got a list of
enum objects taken from various types (say I've got one set of enums
for days of the week, another for months of the year, and so on, and
which I use depends on whether the user wants to select days of the
week, months of the year, etc), it makes perfect sense to want to know
if a specific enum value is in the list, and the obvious way to check
it is with my_value in enum_list. That won't work if you raise an
exception - it takes a relatively convoluted bit of code to make this
test.
The 'enum' package in Cheeseshop doesn't do that. Enumerations are
sequences (of unique arbitrary values), that can be iterated and tested
for membership.
What's being discussed here is what happens when comparing the *values*
from the enumeration.
Python generally uses '==' to mean is the same value. To do that,
a simple true/false return is enough. In raising an exception,
you're making '==' carry an extra meaning (I'm not sure *what* that
is, though).
The problem with is the same value as an explanation for '==' is
that it doesn't help in cases such as::
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
What should be the result of this comparison::
ShirtSize.small == AppleSize.small
Are they the same value? They're both small (and they both coerce
to the same string value, and in this case the same integer value).
If not, is 'False' the right way to indicate that?
Or is it an error to even try comparing them?
Do any python builtins behave that way? How about anything in the
python standard library?
No to both; I believe this may be a defining property of
enumerations. Am I wrong?
--
\ Man cannot be uplifted; he must be seduced into virtue. -- |
`\ Donald Robert Perry Marquis |
_o__) |
Ben Finney
--
http://mail.python.org/mailman/listinfo/python-list
Re: split string saving screened spaces
Sergey wrote: Which module to use to do such thing: -a -b -c '1 2 3' - [-a, -b, -c, '1 2 3'] import shlex shlex.split(-a -b -c '1 2 3') ['-a', '-b', '-c', '1 2 3'] -- Giovanni Bajo -- http://mail.python.org/mailman/listinfo/python-list
Re: split string saving screened spaces
Sergey wrote: Which module to use to do such thing: -a -b -c '1 2 3' - [-a, -b, -c, '1 2 3'] (i have string, need to pass it to getopt) seems like CSV except that the seperator is space. You may check to see if the CSV module can take space as delimiter. -- http://mail.python.org/mailman/listinfo/python-list
Python and curses
Was wanting to write a text based application in python seems curses module is the way to go... anyone knows of any good tutorials apart from the one written by esr -- http://mail.python.org/mailman/listinfo/python-list
Python IDE
Which is a better python IDE SPE or WingIDE in terms of features -- http://mail.python.org/mailman/listinfo/python-list
Re: getsockopt
--- Ursprüngliche Nachricht ---
Von: Steve Holden [EMAIL PROTECTED]
An: python-list@python.org
Betreff: Re: getsockopt
Datum: Fri, 16 Dec 2005 08:29:08 +
Fabian Deutsch wrote:
Hello,
my name is fabian and i'm a student from northern germany. right now i
try to create som kind of decapsulation of esp-udp packets using python.
therefor i need to use the socket.getsockopt (SOL_IP, IP_OPTIONS, 20)
method. But al i get is some empty value. Nothin.
Does someone know or have an working exmaple of how to use this method??
The lines:
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)
s.bind(('',4500))
while 1:# Run until cancelled
message, client = s.recvfrom(1400) # =256 byte datagram
hdr = s.getsockopt (SOL_IP, IP_OPTIONS, 20)
print Client connected:, client
print HDR: + binascii.hexlify(hdr)
Perhaps you're getting an empty string back because no IP options are
set in the received packets' headers?
Hey,
you are right - i just re-read the ip (7) man - i only get the ip options ..
but do you know a way of getting the whole header?
'cause what i'm trying to do is, to remove the udp-header of the packet i
recieved and sendind a new packet without the udp-header.
I want to do this by taking it's payload (incl. esp-hdr) and ip-header and
resending it to my system creating a new packet with the old ip-header and
payload (incl. esp-hdr) i got from the recvd packet.
Before:
++-+--+--- - -
| IP HDR | UDP HDR | ESP HDR | PAYLOAD ...
++-+--+--- - -
After :
++-+--- - -
| IP HDR | ESP HDR | PAYLOAD ...
++-+--- - -
regards
fabian
--
Fabian Deutsch [EMAIL PROTECTED]
--
http://mail.python.org/mailman/listinfo/python-list
Re: newbie to python
Hello,
Here is the script then the problem.
cat testing.py
import crypt
import random, string
def getsalt(chars = string.letters + string.digits):
return random.choice(chars) + random.choice(chars)
username = raw_input('password : ')
print crypt.crypt(username,getsalt())
python testing.py
password : testing
Traceback (most recent call last):
File testing.py, line 1, in ?
import crypt
File /home/testing/scripts/crypt.py, line 4, in ?
TypeError: 'module' object is not callable
--
http://mail.python.org/mailman/listinfo/python-list
Re: newbie to python
Johhny wrote:
Here is the script then the problem.
cat testing.py
import crypt
import random, string
def getsalt(chars = string.letters + string.digits):
return random.choice(chars) + random.choice(chars)
username = raw_input('password : ')
print crypt.crypt(username,getsalt())
python testing.py
password : testing
Traceback (most recent call last):
File testing.py, line 1, in ?
import crypt
File /home/testing/scripts/crypt.py, line 4, in ?
Read carefully. You have a file /home/testing/scripts/crypt.py which is
imported instead of the crypt module in Python's standard library.
Rename /home/testing/scripts/crypt.py to something else, delete
/home/testing/scripts/crypt.pyc, and all should be well.
Peter
--
http://mail.python.org/mailman/listinfo/python-list
Re: getsockopt
Fabian Deutsch wrote:
--- Ursprüngliche Nachricht ---
Von: Steve Holden [EMAIL PROTECTED]
An: python-list@python.org
Betreff: Re: getsockopt
Datum: Fri, 16 Dec 2005 08:29:08 +
Fabian Deutsch wrote:
Hello,
my name is fabian and i'm a student from northern germany. right now i
try to create som kind of decapsulation of esp-udp packets using python.
therefor i need to use the socket.getsockopt (SOL_IP, IP_OPTIONS, 20)
method. But al i get is some empty value. Nothin.
Does someone know or have an working exmaple of how to use this method??
The lines:
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)
s.bind(('',4500))
while 1:# Run until cancelled
message, client = s.recvfrom(1400) # =256 byte datagram
hdr = s.getsockopt (SOL_IP, IP_OPTIONS, 20)
print Client connected:, client
print HDR: + binascii.hexlify(hdr)
Perhaps you're getting an empty string back because no IP options are
set in the received packets' headers?
Hey,
you are right - i just re-read the ip (7) man - i only get the ip options ..
but do you know a way of getting the whole header?
'cause what i'm trying to do is, to remove the udp-header of the packet i
recieved and sendind a new packet without the udp-header.
I want to do this by taking it's payload (incl. esp-hdr) and ip-header and
resending it to my system creating a new packet with the old ip-header and
payload (incl. esp-hdr) i got from the recvd packet.
Before:
++-+--+--- - -
| IP HDR | UDP HDR | ESP HDR | PAYLOAD ...
++-+--+--- - -
After :
++-+--- - -
| IP HDR | ESP HDR | PAYLOAD ...
++-+--- - -
I'm not sure where ESP is going to come into this, or how the traffic
you will be receiving will be generated. I suspect you may need to
reconsider your application design a little.
The only way to get hold of the IP headers is to use SOCK_RAW, which
delivers everything that comes in from the packet driver.
What is it you're actually trying to do? If you perform the
transformation you outline in the diagrams above then the IP header will
certainly contain the wrong protocol value for a start.
regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.python.org/pycon/
--
http://mail.python.org/mailman/listinfo/python-list
Re: 0 in [True,False] returns True
Op 2005-12-15, Grant Edwards schreef [EMAIL PROTECTED]: On 2005-12-15, Antoon Pardon [EMAIL PROTECTED] wrote: Well, in my case, a given name (or return value) is always bound to a floating point object. I don't test the type of the object and treat it in two different ways depending on what type it is. It's just a float. Do you find that difference so important? Possibly. In my case, a float is always a float. You can always do the same set of operations on it. As far as I understand the gtk identifiers are always positive integers. So I could have coded as follows: UnConnected = (-1, -2) Registered, UnRegistered = UnConnected In your case, there isn't a single set of operations that work regardles of the value. You have to _check_ the value in order to decide what operations are allowed on that value. I'm not saying the latter is evil but I think the distinction is important. ... if self.cb_src in UnConnected: Now all values are integers and I no longer treat an object different depending on type but on value. However conceptually nothing changed. My code branches depending on set membership of this attribute. Could you explain why it should make a (big) difference between these two approaches? Your examples are still both very different from the NaN example. A NaN is a floating point operation that supports all the same operations as all other floating point operations. In your example an integer object of -2 does not support the same operations that a real GTK identifier does. They are two different types. I think the disctinction you are making is based on which level you look at things. For you floats are something you use, you see NaN as just a floats because the details of implementation have been abstracted out for you. But look at it from the level of someone who has to implement floating point numbers. He can't just take two floats and put them into his general add_float algorithm. If he did that the result of working with a NaN could result in a regular number. So he has to test for special values like NaN is his 'code' too. Of course we tend to forget this because in this case the abstraction is usually done at the hardware level. But I don't think that is such an important disctinction here. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: CherryPy wiki not working
Yes, it looks like some type of virus has affected my computer. CherryPy was fine from home using my IMac. But at work from both Firefox and IE I get this problem and now it has affected another site. The URLs at CherryPy look like this : http://www.cherrypy.org/store/0_1_540744_1_1_index.html Still, not a Python problem. Bill -- http://mail.python.org/mailman/listinfo/python-list
Re: getsockopt
Stave Holde wrote:
Fabian Deutsch wrote:
--- Ursprüngliche Nachricht ---
Von: Steve Holden [EMAIL PROTECTED]
An: python-list@python.org
Betreff: Re: getsockopt
Datum: Fri, 16 Dec 2005 08:29:08 +
Fabian Deutsch wrote:
Hello,
my name is fabian and i'm a student from northern germany. right now i
try to create som kind of decapsulation of esp-udp packets using
python.
therefor i need to use the socket.getsockopt (SOL_IP, IP_OPTIONS, 20)
method. But al i get is some empty value. Nothin.
Does someone know or have an working exmaple of how to use this
method??
The lines:
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)
s.bind(('',4500))
while 1:# Run until cancelled
message, client = s.recvfrom(1400) # =256 byte datagram
hdr = s.getsockopt (SOL_IP, IP_OPTIONS, 20)
print Client connected:, client
print HDR: + binascii.hexlify(hdr)
Perhaps you're getting an empty string back because no IP options are
set in the received packets' headers?
Hey,
you are right - i just re-read the ip (7) man - i only get the ip
options ..
but do you know a way of getting the whole header?
'cause what i'm trying to do is, to remove the udp-header of the
packet i
recieved and sendind a new packet without the udp-header.
I want to do this by taking it's payload (incl. esp-hdr) and ip-header
and
resending it to my system creating a new packet with the old ip-header
and
payload (incl. esp-hdr) i got from the recvd packet.
Before:
++-+--+--- - -
| IP HDR | UDP HDR | ESP HDR | PAYLOAD ...
++-+--+--- - -
After :
++-+--- - -
| IP HDR | ESP HDR | PAYLOAD ...
++-+--- - -
I'm not sure where ESP is going to come into this, or how the traffic
you will be receiving will be generated. I suspect you may need to
reconsider your application design a little.
The only way to get hold of the IP headers is to use SOCK_RAW, which
delivers everything that comes in from the packet driver.
What is it you're actually trying to do? If you perform the
transformation you outline in the diagrams above then the IP header will
certainly contain the wrong protocol value for a start.
Well actually I managed to recieve the encapsulated esp packages,
decapsulate them and send them to my system using
sr = socket(AF_INET, SOCK_RAW, IPPROTO_ESP)
...
sr.sendto(message (MY_IP,0))
it does work and my system correctly deciphers the packages (i get an icmo
oing request and my system answers with icmp reply) but the problem is, that
the src_adr of the esp_package is set to my local adr and not the adr of the
original esp-udp_packet sender ... so i try to use
sr.send
to send the message, but then i will have to create the whole header ... but
i dont't want to create it but copy it from the recived packet to the new
one ..
i hope you understand what i am trying to say ..
fabian
--
Fabian Deutsch [EMAIL PROTECTED]
--
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Re: Enumeration idioms: Values from different enumerations
Op 2005-12-16, Ben Finney schreef [EMAIL PROTECTED]:
Mike Meyer [EMAIL PROTECTED] writes:
Peter Hansen [EMAIL PROTECTED] writes:
That is, [perhaps] trying to compare enumerations that should not
be compared *is* an error (raising an exception) *because* the
whole point of enumerations is to avoid errors in such cases.
Except it might not be an error. For instance, if I've got a list of
enum objects taken from various types (say I've got one set of enums
for days of the week, another for months of the year, and so on, and
which I use depends on whether the user wants to select days of the
week, months of the year, etc), it makes perfect sense to want to know
if a specific enum value is in the list, and the obvious way to check
it is with my_value in enum_list. That won't work if you raise an
exception - it takes a relatively convoluted bit of code to make this
test.
The 'enum' package in Cheeseshop doesn't do that. Enumerations are
sequences (of unique arbitrary values), that can be iterated and tested
for membership.
Sure but we do have this:
from enum import Enum
day = Enum('mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun')
col = Enum('red', 'green', 'blue')
lst= [day.mon, col.red]
col.blue in lst
Traceback (most recent call last):
File stdin, line 1, in ?
File enum.py, line 100, in __cmp__
raise EnumValueCompareError(self, other)
enum.EnumValueCompareError: Not values from the same enumeration:
(EnumValue(enum.Enum object at 0x402181ac, 2, 'blue'),
EnumValue(enum.Enum object at 0x4020c36c, 0, 'mon'))
What's being discussed here is what happens when comparing the *values*
from the enumeration.
Python generally uses '==' to mean is the same value. To do that,
a simple true/false return is enough. In raising an exception,
you're making '==' carry an extra meaning (I'm not sure *what* that
is, though).
The problem with is the same value as an explanation for '==' is
that it doesn't help in cases such as::
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
What should be the result of this comparison::
ShirtSize.small == AppleSize.small
Are they the same value? They're both small (and they both coerce
to the same string value, and in this case the same integer value).
If not, is 'False' the right way to indicate that?
I would agree 'False' is the right answer here.
--
Antoon Pardon
--
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Re: RoR like (was : SPE 0.8.1.b Python IDE...)
Adrian Holovaty wrote:
bruno at modulix wrote:
RoR is not an IDE, it's a web framework. The closest things in Python
are TurboGears (good Ajax/js support via Mochikit), Subway (never
tested), and Django (no Ajax support AFAIK).
Note that no Ajax support is misleading. Of course you can use Ajax
with Django, just as you can use it with *any* Web framework. That's
because Ajax is a browser-side technology (JavaScript), not a
server-side technology (Python). Django is just as capable of producing
JavaScript as it is of producing (X)HTML or whatever else.
Hope that clears things up!
Adrian, what you describe here is *exactly* what I call no Ajax
support: you have to handle the whole thing manually, the framework
doesn't provide anything by itself. Would you say the CGI module offers
support for templating, data persistance and Ajax as well ?-)
And BTW, Ajax is not a client-side techno, it's a combination of client
*and* server-side technos. TurboGears support Ajax (well, a variant of,
since it's based on JSON, not XML) by having a pretty good, JSON aware
javascript lib (mochikit) for the client side *and* an OOTB JSON
serialization on the server side.
Hope that clears things up !-)
(PS : please, let's not start a Django-vs-TurboGears war, the
Ruby-Python pissing context is enough of a PITA)
--
bruno desthuilliers
python -c print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])
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thread and alarm
How to send alarm to a thread? I can set alarm in main thread, but how then send exception to another thread to wake it if it executes too long? -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Ben Finney wrote:
The problem with is the same value as an explanation for '==' is
that it doesn't help in cases such as::
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
What should be the result of this comparison::
ShirtSize.small == AppleSize.small
Are they the same value? They're both small (and they both coerce
to the same string value, and in this case the same integer value).
Is it possible to make it have the following sort of behaviour? :
ShirtSize.small == AppleSize.small
True
ShirtSize.small is AppleSize.small
False
It works for comparing a boolean (True) vs. an integer (1), so it has
some sort of precedent. (Especially if you make the tenuous assumption
that True,False are language-supported 'enums' for 0 and 1.)
--
Ben Sizer
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text manipulation
Hello, I am trying to write a script in python (to replace a perl script with limited functionality). Now I have some issues. Currently I am using the perl to load the file then regex parse certain lines to remove characters (uncomment lines and change variables). I would like to take that into the python script. I have had a look at the module string and I dont think its what Im looking for. Here is an example of some text I would like to manipulate #comment here #user_defined_variable = no # I would like to make that #comment here user_defined_variable = yes # With perl/sed Its very easy, However Im having issues to do it in python. Any advice would be great. Regards, Johhny. -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Op 2005-12-16, Ben Sizer schreef [EMAIL PROTECTED]:
Ben Finney wrote:
The problem with is the same value as an explanation for '==' is
that it doesn't help in cases such as::
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
What should be the result of this comparison::
ShirtSize.small == AppleSize.small
Are they the same value? They're both small (and they both coerce
to the same string value, and in this case the same integer value).
Is it possible to make it have the following sort of behaviour? :
ShirtSize.small == AppleSize.small
True
ShirtSize.small is AppleSize.small
False
It works for comparing a boolean (True) vs. an integer (1), so it has
some sort of precedent. (Especially if you make the tenuous assumption
that True,False are language-supported 'enums' for 0 and 1.)
I'm against it. I don't like the following returning True:
ShirtSize.small in [ShirtSize.Medium, AppleSize.small]
I also think it may cause problems with other comparisons.
Supose the following:
col = Enum('red', 'green', 'blue')
paint = Enum('violet' , 'blue', 'red')
Then we get the following situation:
col.red == paint.red and col.blue == paint.blue
but
col.red col.blue and paint.blue paint.red
--
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Re: text manipulation
Johhny wrote: Any advice would be great. Have you had a look at Python's re module? If you've not, I suggest you do so - it contains all of Python's regex tools which you'll need. Regards, -- Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: Clearing the Tkinter Window
James Stroud wrote: Dustan wrote: I'm a newbie here, especially with Tkinter. I'm writing a program that has 3 phases, if you will, in which I would have to clear the window and insert new widgets. Is this possible, and if so, how? I'm writing my application class based on Frame, if that helps at all. Its not obvious what you are asking. But, if you populate a Frame with widgets, then you can destroy those widgets if you destroy the Frame: tk = Tk() f = Frame(tk) # fill frame with 10 buttons for i in xrange(10): Button(f, text=str(i)).pack() # kill the frame and buttons f.destroy() # references to buttons gone too, so they are GC'd # make a new frame and put it in tk f = Frame(tk) # etc. You will want to make sure any name assignments are re-assigned, del'd, or go out of scope after you destroy frame, or the button objects won't be garbage collected, even though they are destroyed when the frame is destroyed. James destroy is one way to do it... but if you need to access the destroyed widgets information after they have gone it may cause problems.. another method to look at is (are) the *_forget methods (pack_forget / grid_forget) these do not destroy the widgets but rather remove them from view. If for example you are writing a 'wizard' type GUI and want to show the user the 'Next' page simply forget the current page and pack the next one in it's place. Another way is to grid each 'page' over the top of each other and simply change the 'raise' order (with tkraise method) not 100% sure if this works though, i've not used it directly myself... Cheers Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: Robotics and parallel ports
Thanks for everyone's tips and hints. I WILL MAKE THIS WORK! I think I'll take your advice and use the serial port instead of the parallel port - I won't have that much data to send (in comparison with, for example, industrial level applications). As for on-board chips though, does this require low level programming!? Or can I have an embedded python interpreter for the chip? Many thanks. Regards, -- Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: tkinter: drop-down widget
James Stroud wrote: Alex Hunsley wrote: Can anyone recommend some code for creating drop-down menus in tkinter? To be absolutely clear, here's an example of a drop-down: http://www.google.co.uk/preferences?hl=en (see the language selection widget) I've found the odd bit of code here and there, such as: http://infohost.nmt.edu/tcc/cgi/pre.cgi?file=/u/www/docs/tcc/help/lang/python/mapping/dropdown.py alex Try: 1. Tkinter OptionMenu: http://effbot.org/tkinterbook/optionmenu.htm 2. Pmw OptionMenu: http://pmw.sourceforge.net/doc/OptionMenu.html I would opt for these before a roll-your-own version. Thanks for those! :) alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Python and curses
linuxfreak [EMAIL PROTECTED] writes: Was wanting to write a text based application in python seems curses module is the way to go... anyone knows of any good tutorials apart from the one written by esr There is at least 1 higher level library atop curses. http://excess.org/urwid/ I've only played with it a little bit but it looks useful. Eddie -- http://mail.python.org/mailman/listinfo/python-list
Re: Python and curses
linuxfreak wrote: Was wanting to write a text based application in python seems curses module is the way to go... anyone knows of any good tutorials apart from the one written by esr Not off the top of my head, no. However, you will find that the functions needed will be very similar to the C functions used. I did this with PHP a while back and (because there are a lack of tutorials for PHP too) I had to resort to the man pages for it. So I'd suggest reading that tutorial (by esr or whoever) and then just reading the man pages for C for more documentation. Regards, -- Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: text manipulation
Johhny wrote: Hello, I am trying to write a script in python (to replace a perl script with limited functionality). Now I have some issues. Currently I am using the perl to load the file then regex parse certain lines to remove characters (uncomment lines and change variables). I would like to take that into the python script. I have had a look at the module string and I dont think its what Im looking for. Here is an example of some text I would like to manipulate #comment here #user_defined_variable = no # I would like to make that #comment here user_defined_variable = yes # With perl/sed Its very easy, However Im having issues to do it in python. Any advice would be great. Regards, Johhny. forget regular expressions for this job... strings have methods in python so for example: for line in file: if line.startswith(#user_defined_variable = no): line.replace(#user_defined_variable = no, user_defined_variable = yes) ... continue processing file / writing out stuff as you go Cheers Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: tkinter: drop-down widget
James Stroud wrote: Alex Hunsley wrote: Can anyone recommend some code for creating drop-down menus in tkinter? To be absolutely clear, here's an example of a drop-down: http://www.google.co.uk/preferences?hl=en (see the language selection widget) I've found the odd bit of code here and there, such as: http://infohost.nmt.edu/tcc/cgi/pre.cgi?file=/u/www/docs/tcc/help/lang/python/mapping/dropdown.py alex Try: 1. Tkinter OptionMenu: http://effbot.org/tkinterbook/optionmenu.htm 2. Pmw OptionMenu: http://pmw.sourceforge.net/doc/OptionMenu.html I would opt for these before a roll-your-own version. try searching for a ComboBox I think you will have more hits I know Pmw has one, it is also quite easy to build your own with an Entry, Button and Listbox widget + some nifty code ;) Cheers, Martin. -- http://mail.python.org/mailman/listinfo/python-list
Re: text manipulation
Martin Franklin wrote: Johhny wrote: Hello, I am trying to write a script in python (to replace a perl script with limited functionality). Now I have some issues. Currently I am using the perl to load the file then regex parse certain lines to remove characters (uncomment lines and change variables). I would like to take that into the python script. I have had a look at the module string and I dont think its what Im looking for. Here is an example of some text I would like to manipulate #comment here #user_defined_variable = no # I would like to make that #comment here user_defined_variable = yes # With perl/sed Its very easy, However Im having issues to do it in python. Any advice would be great. Regards, Johhny. forget regular expressions for this job... strings have methods in python so for example: for line in file: if line.startswith(#user_defined_variable = no): line.replace(#user_defined_variable = no, user_defined_variable = yes) ... continue processing file / writing out stuff as you go Cheers Martin whoops forgot string methods return the new string. for line in file: if line.startswith(#user_defined_variable = no): line = line.replace(#user_defined_variable = no, user_defined_variable = yes) -- http://mail.python.org/mailman/listinfo/python-list
Re: text manipulation
Johhny wrote:
Hello,
I am trying to write a script in python (to replace a perl script with
limited functionality). Now I have some issues. Currently I am using
the perl to load the file then regex parse certain lines to remove
characters (uncomment lines and change variables). I would like to take
that into the python script. I have had a look at the module string
and I dont think its what Im looking for.
Here is an example of some text I would like to manipulate
#comment here
#user_defined_variable = no
#
I would like to make that
#comment here
user_defined_variable = yes
#
With perl/sed Its very easy, However Im having issues to do it in
python. Any advice would be great.
Regards,
Johhny.
Have you also looked at the built-in string methods?
The following script is probably something you
could start with - it just uncomments lines
and replaces values of some variables.
# dictionary of the variable names
# contains the replacement values
newvalues = {'userdefinedvar1':'yes',
'userdefinedvar2':'123.654.345.234'}
# read file to input
output = []
for line in input:
# check if it is a comment with =
if line.startswith('#') and ('=' in line):
name, oldvalue = (line.lstrip('#')).split('=')
# line.lstrip removes leading comments,
# split('=') finds the assignment
if newvalues.has_key(name):
# replace line
output.append(%s = %s % (name, newvalue[name]))
else:
# or just uncomment
output.append(%s = %s % (name, oldvalue))
else:
output.append(line)
# write output to file
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Re: SVG rendering with Python
Matplotlib also has an SVG renderer. Just save the file with an SVG extension or choose SVG as your default backend in the rc file http://matplotlib.sf.net/matplotlibrc. -- http://mail.python.org/mailman/listinfo/python-list
Re: thread and alarm
Op 2005-12-16, Sergey schreef [EMAIL PROTECTED]: How to send alarm to a thread? I can set alarm in main thread, but how then send exception to another thread to wake it if it executes too long? The short answer is you can't and you should preferably look for an other solution. If for example your other thread is simple loop like: while condition: ... You could change this to: while not timeout and condition: timeout is then a variable that could be set by a differnt thread. If your code doesn't lend itself for this kind of solution you could consider the following module I once wrote. However some caveats: 1) You need ctypes. 2) It can only interrupt a thread while it is excuting python code. No interruptions while in C-extention code. 3) It is not extensivly tested. It was just a proof of concept thing. import os import ctypes from time import sleep from random import randint class TimeOut(Exception): pass class Alarm(Exception): pass import threading class Xthread(threading.Thread): def start(self): self.__original_run = self.run self.run = self.__run threading.Thread.start(self) def __run(self): self._thrd_id = threading._get_ident() try: self.__original_run() finally: self.run = self.__original_run def raize(self, excpt): Nr = ctypes.pythonapi.PyThreadState_SetAsyncExc(self._thrd_id, ctypes.py_object(excpt)) #print self.id , Exception Thrown , Nr while Nr 1: #print self.id , Exception Canceled , Nr ctypes.pythonapi.PyThreadState_SetAsyncExc(self._thrd_id, None) sleep(0.1) Nr = ctypes.pythonapi.PyThreadState_SetAsyncExc(self._thrd_id, ctypes.py_object(excpt)) #if Nr == 0: # print self.id , Exception Canceled , Nr # ctypes.pythonapi.PyThreadState_SetAsyncExc(self._thrd_id, None) def alarm(self, tm): alrm = threading.Timer(tm, self.raize, (TimeOut,)) alrm.start() return alrm if __name__ == __main__: class Continue(Xthread): def run(self): self.id = os.getpid() print self.id, self._thrd_id, Begin i = 0 try: for _ in xrange(randint(0,20)): for e in xrange(4 * 10): i = i + e print self.id, Finished except Alarm: print self.id, Interupted lst = [Continue() for _ in xrange(10)] for T in lst: T.start() try: sleep(10) finally: for T in lst: T.raize(Alarm) -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with Lexical Scope
On 15 Dec 2005 18:45:17 -0800, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Well, the the comparison operations are just a special case really.I
don't know about the obfuscation contest. I've attempted to make an
extensible library.
Sorry about obfuscation contest, I just balked at the reduce code, which
seemed
like premature overgeneralization ;-)
def lt(*fields):
return collect(fields, lambda x, y: x y)
def gt(*fields):
return collect(fields, lambda x, y: x y)
def gte(*fields):
gte(field, ...) - rule
return collect(fields, lambda x, y: x = y)
etc...
DRY ? ;-)
The purpose of writing the collect function was just to be able to
easily apply the logic to whatever function was wanted.
the added ability is to be able to take as many arguments as it wants.
Yes, but does collect(fields, fun) always know that fun takes two args? And that
it makes sense to apply fun pairwise as a boolean relation to reduce to a
single boolean value?
You could say that by definition it does. In that case, will your future
library extender need
to add some other kind of collect-like function?
hire_rule = lt('birth_date', 'hire_date', 'fire_date')
cube_rule = eq('height', 'width', 'depth')
I see where the idea of using reduce would occur ;-)
The reason that it's written like this is because I'm attempting to
make things as declarative as possible. I could use classes and
override __special__ operators and things like that but just applying
rules using prefix notation seems to work alright.
Applying or generating? But yeah, prefix should work fine. Or infix.
I've basically got a simple call signature...takes dict returns bool
that plugs into the little validation routine.
Simple is good.
It turns out that envoking the rules is easistly expressed with a
closure, though I might switch to types if it needs that added
complexity.
It's good that you have a syntax that can be implemented either way.
But your assumption is correct, it's for dictionaries of data to be
validated. I haven't decided if I want to take advantage of the dict's
mutability to include formating as well.
You might consider putting formatting in dict subclasses that have appropriate
__str__ and/or __repr__ methods, and doing print Fmtxxx(record_dict) or such?
Here's a bit from my unit test.
Looks nice. And the syntax is regular enough that you can probably
write an optimizing rule generator when/if you need it.
rule = when(all(have('length'), have('width')),
check(['length', 'width'], lambda x, y: x == y))
assert rule({'length' : '2', 'width' : '2'}) == True
assert rule({'length' : '2', 'width' : '1'}) == False
assert rule({'length' : '1', 'width' : '2'}) == False
But what about when the when clause says the rule does not apply?
Maybe return NotImplemented, (which passes as True in an if test) e.g.,
assert rule({'length' : '1', 'height' : '2'}) is NotImplemented
I've also got a collectable equality function so that can be shown
as.
box_rule = when(all(have('length'), have('width')), eq('length',
'width'))
Which basically means, if we have both a length and a width, then be
sure they are equal.
either way, I think it would be better to give tests names, i.e., instead
of the lambda, pass a function def eq(x,y): return x==y and then also
change check to have signature def check(testfun, *fields):...
But collectable has the possibility of inline code generation (see below ;-)
Of course, there is a little function that performs a conjunction of a
complete list of rules on a dict and returns the rules that failed.
I've also got a little adapter that translates functions that take a
string and returns bool into one that fits the call signature called
match.
match(is_ssn, 'social-security_number')
Like I said, it may be considered more readable if using operator
overloading so that it uses python's native syntax. Considering the
added complexity, I don't know if it would be worth it. I'd probably
put a simple little declarative language on top of it to translate the
function calls before that.
Note that you could treat your when, all, have, and check as code source
generators
and compile a rule as the last part of when processing, e.g.,
(fresh off the griddle, only tested as far as you see ;-)
jslowery.py --
def all(*tests):
return '(' + ' and '.join(tests) +')'
def have(*fields):
return '(' + ' and '.join('%s in record'%field for field in fields) + ')'
def check(tfun, *fields):
return '%s(%s)' % (tfun.func_name, ', '.join('record[%r]'%field for field
in fields))
def when(cond, test):
g = globals()
d = dict((name, g[name]) for name in __testfuns__)
src = \
def rule(record):
if not (%s): return NotImplemented
return (%s)
%(cond, test)
print src # XXX debug
exec src in d
return d['rule']
def eq(*fields): # collectable
return '(' + ' == '.join('record[%r]'%(field,) for field in fields) + ')'
def
Re: Re: getsockopt
Steve Holden wrote:
Fabian Deutsch wrote:
--- Ursprüngliche Nachricht ---
Von: Steve Holden [EMAIL PROTECTED]
An: python-list@python.org
Betreff: Re: getsockopt
Datum: Fri, 16 Dec 2005 08:29:08 +
Fabian Deutsch wrote:
Hello,
my name is fabian and i'm a student from northern germany. right now i
try to create som kind of decapsulation of esp-udp packets using
python.
therefor i need to use the socket.getsockopt (SOL_IP, IP_OPTIONS, 20)
method. But al i get is some empty value. Nothin.
Does someone know or have an working exmaple of how to use this
method??
The lines:
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)
s.bind(('',4500))
while 1:# Run until cancelled
message, client = s.recvfrom(1400) # =256 byte datagram
hdr = s.getsockopt (SOL_IP, IP_OPTIONS, 20)
print Client connected:, client
print HDR: + binascii.hexlify(hdr)
Perhaps you're getting an empty string back because no IP options are
set in the received packets' headers?
Hey,
you are right - i just re-read the ip (7) man - i only get the ip
options ..
but do you know a way of getting the whole header?
'cause what i'm trying to do is, to remove the udp-header of the
packet i
recieved and sendind a new packet without the udp-header.
I want to do this by taking it's payload (incl. esp-hdr) and ip-header
and
resending it to my system creating a new packet with the old ip-header
and
payload (incl. esp-hdr) i got from the recvd packet.
Before:
++-+--+--- - -
| IP HDR | UDP HDR | ESP HDR | PAYLOAD ...
++-+--+--- - -
After :
++-+--- - -
| IP HDR | ESP HDR | PAYLOAD ...
++-+--- - -
I'm not sure where ESP is going to come into this, or how the traffic
you will be receiving will be generated. I suspect you may need to
reconsider your application design a little.
The only way to get hold of the IP headers is to use SOCK_RAW, which
delivers everything that comes in from the packet driver.
What is it you're actually trying to do? If you perform the
transformation you outline in the diagrams above then the IP header will
certainly contain the wrong protocol value for a start.
You just need the ipsec tools to generate the traffic i want to decapsulate.
setkey -c EOF
add HOSTA HOSTB esp-udp 11 -m tunnel -E 3des-cbc 123456789012123456789012
spdadd HOSTA HOSTB any -P in ipsec
esp/tunnel/HOSTA-HOSTB/use;
EOF
you will get some udp-esp packets when you ping HOSTB from HOSTA.
- fabian
--
Fabian Deutsch [EMAIL PROTECTED]
Hinter dem Gartel 26a
D-27711 Osterholz-Scharmbeck
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Re: RoR like (was : SPE 0.8.1.b Python IDE...)
bruno at modulix wrote: Adrian, what you describe here is *exactly* what I call no Ajax support: you have to handle the whole thing manually, the framework doesn't provide anything by itself. I'm not going to argue whether Django supports Ajax or not, but I will agree that for the desired effect applications do need to be able to provide something usable for the client-side code to work with. However, all the something usable needs to be, in my opinion, is a fragment of an existing Web page which is accessible through a well-defined Web-style API. And BTW, Ajax is not a client-side techno, it's a combination of client *and* server-side technos. TurboGears support Ajax (well, a variant of, since it's based on JSON, not XML) by having a pretty good, JSON aware javascript lib (mochikit) for the client side *and* an OOTB JSON serialization on the server side. I personally don't believe very strongly in this server-side serialisation of various non-displayable formats for potentially large amounts of client-side code to unpack, process, stuff into different places, and so on. As I said before, this is like reinventing client/server all over again but with the deployment of client-side code and the presentation technology standardised: you still end up with maintenance issues, keeping the data model consistent at both ends whilst dealing with different languages and toolkits. I'd rather have such functionality controlled with mostly declarative constructs, and with as few moving parts on the client as possible. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: RoR like (was : SPE 0.8.1.b Python IDE...)
bruno at modulix wrote: Adrian, what you describe here is *exactly* what I call no Ajax support: you have to handle the whole thing manually, the framework doesn't provide anything by itself. I'm not going to argue whether Django supports Ajax or not, but I will agree that for the desired effect applications do need to be able to provide something usable for the client-side code to work with. However, all the something usable needs to be, in my opinion, is a fragment of an existing Web page which is accessible through a well-defined Web-style API. And BTW, Ajax is not a client-side techno, it's a combination of client *and* server-side technos. TurboGears support Ajax (well, a variant of, since it's based on JSON, not XML) by having a pretty good, JSON aware javascript lib (mochikit) for the client side *and* an OOTB JSON serialization on the server side. I personally don't believe very strongly in this server-side serialisation of various non-displayable formats for potentially large amounts of client-side code to unpack, process, stuff into different places, and so on. As I said before, this is like reinventing client/server all over again but with the deployment of client-side code and the presentation technology standardised: you still end up with maintenance issues, keeping the data model consistent at both ends whilst dealing with different languages and toolkits. I'd rather have such functionality controlled with mostly declarative constructs, and with as few moving parts on the client as possible. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: RoR like (was : SPE 0.8.1.b Python IDE...)
bruno at modulix wrote: Adrian, what you describe here is *exactly* what I call no Ajax support: you have to handle the whole thing manually, the framework doesn't provide anything by itself. I'm not going to argue whether Django supports Ajax or not, but I will agree that for the desired effect applications do need to be able to provide something usable for the client-side code to work with. However, all the something usable needs to be, in my opinion, is a fragment of an existing Web page which is accessible through a well-defined Web-style API. And BTW, Ajax is not a client-side techno, it's a combination of client *and* server-side technos. TurboGears support Ajax (well, a variant of, since it's based on JSON, not XML) by having a pretty good, JSON aware javascript lib (mochikit) for the client side *and* an OOTB JSON serialization on the server side. I personally don't believe very strongly in this server-side serialisation of various non-displayable formats for potentially large amounts of client-side code to unpack, process, stuff into different places, and so on. As I said before, this is like reinventing client/server all over again but with the deployment of client-side code and the presentation technology standardised: you still end up with maintenance issues, keeping the data model consistent at both ends whilst dealing with different languages and toolkits. I'd rather have such functionality controlled with mostly declarative constructs, and with as few moving parts on the client as possible. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Antoon Pardon [EMAIL PROTECTED] writes:
Ben Finney wrote:
The 'enum' package in Cheeseshop [defines enumerations as]
sequences (of unique arbitrary values), that can be iterated and
tested for membership.
Sure but we do have this:
from enum import Enum
day = Enum('mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun')
col = Enum('red', 'green', 'blue')
lst= [day.mon, col.red]
col.blue in lst
[...]
enum.EnumValueCompareError: Not values from the same enumeration:
Yes, that looks like a case in favour of allowing at least equal-value
and not-equal-value comparisons.
The problem with is the same value as an explanation for '==' is
that it doesn't help in cases such as::
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
What should be the result of this comparison::
ShirtSize.small == AppleSize.small
Are they the same value? They're both small (and they both coerce
to the same string value, and in this case the same integer value).
If not, is 'False' the right way to indicate that?
I would agree 'False' is the right answer here.
Antoon Pardon wrote:
Ben Finney wrote:
Would it be better if every Enum instance had its own unique
subclass of EnumValue, that was used to instantiate values for
that enumeration?
If you decide on keeping the current behaviour when comparing
values of different enumerations, I would definitely answer
yes.
If values from different enums were to be compared for equality (and
not raise an exception), would it still be good to have those values
be of different types?
This is a difficult question, because AFAIU python doesn't have
clear guidelines for [comparisons between differing types]. I also
have the impression that comparisons are used for two different
reasons.
The first is compare things in a mathematical kind of way in which
how things are compared is important.
The second is more an ordering mechanisme. Whether a string is
greater than an int or vice versa, is not imporant what is important
is that this order is consistent and can be used in binary searches,
trees and other structures to organise data.
Now python has only one collection of compare operators which can
cause conflicts. For instance, one could impose an order on sets to
use for such structure but that goes against the normal order on
sets which is based on subsets.
The only advise I have here is look at PEP 3000 that states:
Comparisons other than == and != between disparate types will raise
an exception unless explicitly supported by the type.
Which seem to imply that == and != should not raise an exception but
, =, , = should.
This seems like a good guide for a policy on enumerations.
How about this proposal:
Enumerations (instances of Enum) contain a fixed sequence of unique,
arbitrary values. The values within an enumeration are instances of a
type (subclass of EnumValue), unique to that enumeration.
Values from an enumeration can be compared for equality (__eq__,
__ne__) with any other value, and will only return True for the same
value from the same enumeration, otherwise False. Other comparison
operations can be performed only with values from the same
enumeration, otherwise an exception (EnumValueCompareError, subclass
of ValueError) is raised.
This might result in the following simplistic implementation::
class EnumValue(object):
# ...
def __eq__(self, other):
result = False
if self is other:
result = True
return result
def __cmp__(self, other):
if isinstance(other, EnumValue):
if is_same_enumeration(self, other):
result = cmp(self.index, other.index)
else:
raise EnumValueCompareError(self, other)
return result
This gives meaning to the equal value comparisons, but ensures that
other comparisons are errors.
Comments so far?
--
\ I like to fill my bathtub up with water, then turn the shower |
`\on and pretend I'm in a submarine that's been hit. -- Steven |
_o__) Wright |
Ben Finney
--
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Re: newbie to python
Thankyou, I appreciate your help. I did not realise that python would behave that way. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python and curses
linuxfreak [EMAIL PROTECTED] wrote: Was wanting to write a text based application in python seems curses module is the way to go... anyone knows of any good tutorials apart from the one written by esr It wasn't written by esr. He only has his name on it, did none of the work. -- Thomas E. Dickey http://invisible-island.net ftp://invisible-island.net -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Ben Finney [EMAIL PROTECTED] writes: This gives meaning to the equal value comparisons, but ensures that other comparisons are errors. Comments so far? What does copy.copy of an enumeration value do? What happens if you have a list with some enumeration values inside, and you make a deepcopy of it? What happens if you pickle an enum, then unpickle the pickle and compare what comes out to the other enum? All in all, comparing by object identity doesn't sound too good. Maybe you want to have the enum contain its own name internally, and do a string comparison. -- http://mail.python.org/mailman/listinfo/python-list
distutils: build scripts as native executables?
Hello, am I wrong or isn't there a way in distutils to build (compile/link) a native executable and install it among the scripts? It looks like that distutils.CCompiler features a link_executable() method, and build_ext.py has most of the logic needed to track dependencies, include paths and whatnot, but nothing is exposed at a higher level. I was going to subclass build_ext and find a way to piggy-back link_executable() into it instead of link_shared_object(), but I thought I asked before doing useless / duplicate work. -- Giovanni Bajo -- http://mail.python.org/mailman/listinfo/python-list
Re: Which Python web framework is most like Ruby on Rails?
I did a fairly thorough investigation of web frameworks that let us write Python (we didn't care what the framework was written in; merely that it interfaced with Python) for one of the systems I've built this year. I wouldn't call the evaluation of web frameworks a problem - we met our schedules, and the tool evaluation phase was by *far* the shortest phase in the project, taking less than a week. Most of the evaluations were easy - read the description of the framework, and decide that we're working outside the problem space it's desinged for. It certainly wasn't wasted time - I found a tool that I hadn't heard of previously that was nearly perfectly suited to the job at hand. As I read through this thread I can't say that I disagree that having more choices is a 'good thing'. However in your example here - I suspect that you are a bit sharper and have a bit more guts than your average code slinger since you appear to be an independent. You've got to remember that your average corporate programmer - which are the folks driving the popularity of programming languages - isn't that sharp/confident. (I don't mean to insult anyone but that just the facts.) They don't do things like evaluate frameworks and make smart choices. This is why there needs to be obvious and singularly popular frameworks and IDE's for Python so that people don't have to think that hard about it. Take Java for example - for the most part its Eclipse and Struts. I know there are many other choices (I've used them), but even the managers know these terms. Very, very few people I know in the IT world know of 'Python', let alone the name of any web framework or an IDE for Python. One of the great things about Python is its simplicty/clarity. Its a shame that there doesn't also exist a clarity of choice for a web framework for Python or an IDE for that matter. Both of these would go a long way in motivating people to take a look at Python and realizing what great value it has to offer the IT world in solving problems. -- http://mail.python.org/mailman/listinfo/python-list
Re: why does php have a standard SQL module and Python doesn't !?
[EMAIL PROTECTED] wrote: This was my point though: I found the *description* - but no wordon WHICH implementation to get WHERE ? Hmm. - Browse to http://www.python.org - click Documentation - click Database API - click Database Modules (Database modules that implement the DB-API specification.) - read list, find the database of your choice Kent -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Antoon Pardon wrote: Ben Finney wrote: Would it be better if every Enum instance had its own unique subclass of EnumValue, that was used to instantiate values for that enumeration? If you decide on keeping the current behaviour when comparing values of different enumerations, I would definitely answer yes. If values from different enums were to be compared for equality (and not raise an exception), would it still be good to have those values be of different types? Yes, because people who would need a quick and dirty ordering could then use the type of the object as a first key. The only advise I have here is look at PEP 3000 that states: Comparisons other than == and != between disparate types will raise an exception unless explicitly supported by the type. Which seem to imply that == and != should not raise an exception but , =, , = should. This seems like a good guide for a policy on enumerations. How about this proposal: Enumerations (instances of Enum) contain a fixed sequence of unique, arbitrary values. The values within an enumeration are instances of a type (subclass of EnumValue), unique to that enumeration. Values from an enumeration can be compared for equality (__eq__, __ne__) with any other value, and will only return True for the same value from the same enumeration, otherwise False. Other comparison operations can be performed only with values from the same enumeration, otherwise an exception (EnumValueCompareError, subclass of ValueError) is raised. Looks good to me. This might result in the following simplistic implementation:: class EnumValue(object): # ... def __eq__(self, other): result = False if self is other: result = True return result def __cmp__(self, other): if isinstance(other, EnumValue): if is_same_enumeration(self, other): result = cmp(self.index, other.index) else: raise EnumValueCompareError(self, other) return result This gives meaning to the equal value comparisons, but ensures that other comparisons are errors. Comments so far? Isn't there an else missing? I have the impression that if you compare two enums from a different enumeration __cmp__ will raise UnboundLocalError. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
Re: Robotics and parallel ports
Hi, Thank you for the info. The dlp usb solution looks like a terrific gadget, especially since parallel ports have almost disppeared, at least on portables. In fact, would in linux not any py software capable of dealing with a usb connection (almost) suffice? Any further comments would be much appreciated. malv -- http://mail.python.org/mailman/listinfo/python-list
Re: split string saving screened spaces
Pyparsing has built-in quoted string support.
from pyparsing import OneOrMore,Word,alphanums,quotedString
item = Word('-',alphanums) | quotedString | Word(alphanums)
items = OneOrMore(item)
print items.parseString( -a -b -c '1 2 3' -d 5 -e zork2000 )
gives:
['-a', '-b', '-c', '1 2 3', '-d', '5', '-e', 'zork2000']
Download pyparsing at http://pyparsing.sourceforge.net.
-- Paul
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Re: text manipulation
John, Martin is right. Always try to solve without regex first. However, for those situations where you definitely need regex, use this tutorial: http://www.amk.ca/python/howto/regex/ It's well-written, succinct, and Python-specific. rpd -- http://mail.python.org/mailman/listinfo/python-list
Re: Python IDE
emacs, best ide of all-time ;) -- http://mail.python.org/mailman/listinfo/python-list
Re: Can Python write foreign characters to the console?
On 2005-12-16, Bock [EMAIL PROTECTED] wrote: I was just told about Python. My searching and reading over the net I was able to learn that Python can handle foreign characters via Unicodes. Can or does Python write unicode to the screen? Sure. For example, in c++ cout Hello World. would send this string to the screen/monitor. I want to find a programming language that can write German üßäö as screen output? All of the languages I've ever used could write unicode to a console. Whether your console understands Unicode and displays it properly is another question. Most programming languages/operating systems in North America limit one to the 127 characters of ascii. If that's true, then you're using crap for an OS. -- Grant Edwards grante Yow! Either CONFESS now or at we go to PEOPLE'S COURT!! visi.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Clearing the Tkinter Window
I don't want to destroy the root, I just want to remove the widgets (the exact opposite of what Martin was saying). I started working on James' idea, but it'll be a while before I have it fully implemented to test. -- http://mail.python.org/mailman/listinfo/python-list
Re: 0 in [True,False] returns True
On 2005-12-16, Antoon Pardon [EMAIL PROTECTED] wrote: Your examples are still both very different from the NaN example. A NaN is a floating point operation that supports all the same operations as all other floating point operations. In your example an integer object of -2 does not support the same operations that a real GTK identifier does. They are two different types. I think the disctinction you are making is based on which level you look at things. Of course. I was looking at things from a Python point of view since this is c.l.p. For you floats are something you use, you see NaN as just a floats because the details of implementation have been abstracted out for you. That goes without saying for anything in computer science or electronics: it's all just quantum physics whose details of implimentation have been abstracted out for me. But look at it from the level of someone who has to implement floating point numbers. He can't just take two floats and put them into his general add_float algorithm. If he did that the result of working with a NaN could result in a regular number. So he has to test for special values like NaN is his 'code' too. Of course we tend to forget this because in this case the abstraction is usually done at the hardware level. But I don't think that is such an important disctinction here. The distinction is in regards to readability and maintainability of _Python_ code. This is comp.lang.python. -- Grant Edwards grante Yow! does your DRESSING at ROOM have enough ASPARAGUS? visi.com -- http://mail.python.org/mailman/listinfo/python-list
Problem with exec
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
When I execute this I get the following error:
Traceback (most recent call last):
File mod1.py, line 13, in ?
foo()
File mod1.py, line 10, in foo
exec assign() in dct
File string, line 1, in ?
File mod1.py, line 5, in assign
setattr(config, 'Start' , [13, 26, 29, 34])
NameError: global name 'config' is not defined
Now I don't understand this. In the documentation I read the following:
If only the first expression after in is specified, it should be a
dictionary, which will be used for both the global and the local
variables.
I provided a dictionary to be used for the global variables and it
contains a 'config' entry, so why doesn't this work?
--
Antoon Pardon
--
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Re: Enumeration idioms: Values from different enumerations
Antoon Pardon wrote:
Op 2005-12-16, Ben Sizer schreef [EMAIL PROTECTED]:
Is it possible to make it have the following sort of behaviour? :
ShirtSize.small == AppleSize.small
True
ShirtSize.small is AppleSize.small
False
It works for comparing a boolean (True) vs. an integer (1), so it has
some sort of precedent. (Especially if you make the tenuous assumption
that True,False are language-supported 'enums' for 0 and 1.)
I'm against it. I don't like the following returning True:
ShirtSize.small in [ShirtSize.Medium, AppleSize.small]
I agree to an extent. I can see that being unwanted behaviour, although
not really a big one, and no worse than in C++. I think that when you
have a list of alternatives like that, they're either hard-coded by
selectively picking from the enumeration's initialisation list, or by
being generated according to some other criteria. Either way, it would
be hard to end up with the wrong type of value into that list, I think.
I also think it may cause problems with other comparisons.
Supose the following:
col = Enum('red', 'green', 'blue')
paint = Enum('violet' , 'blue', 'red')
Then we get the following situation:
col.red == paint.red and col.blue == paint.blue
but
col.red col.blue and paint.blue paint.red
I don't think that's a problem - does any other language make any
guarantees on ordering across multiple enumerations? Transitivity
within any single enumeration plus transivity of equivalence across
multiple enumerations, should be enough for most needs, no?
--
Ben Sizer
--
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Re: Clearing the Tkinter Window
Dustan [EMAIL PROTECTED] wrote: I don't want to destroy the root, I just want to remove the widgets (the exact opposite of what Martin was saying). I started working on James' idea, but it'll be a while before I have it fully implemented to test. each widget has a children attribute, which contains a dictionary with Tk widget names as keys, and Python widget objects as values. to destroy all child widgets, you can simply do: for w in widget.children.values(): w.destroy() where widget is the widget you want to reset. /F -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with os.path
Daya Kiran Sunkara wrote: ... path = 'E:\mktrisk\service\marketdata\da' You should use: path = r'E:\mktrisk\service\marketdata\da' if you want to use backslashes regularly (for regexps and paths). You do know you could also use: path = 'E:/mktrisk/service/marketdata/da' even on windows. --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Python IDE
SPE is very good - I'd use it, and if you need any features Stani is very quick to add them. All the best, Fuzzyman http://www.voidspace.org.uk/python/index.shtml -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with exec
Antoon Pardon wrote:
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
When I execute this I get the following error:
Traceback (most recent call last):
File mod1.py, line 13, in ?
foo()
File mod1.py, line 10, in foo
exec assign() in dct
File string, line 1, in ?
File mod1.py, line 5, in assign
setattr(config, 'Start' , [13, 26, 29, 34])
NameError: global name 'config' is not defined
Now I don't understand this. In the documentation I read the following:
If only the first expression after in is specified, it should be a
dictionary, which will be used for both the global and the local
variables.
I provided a dictionary to be used for the global variables and it
contains a 'config' entry, so why doesn't this work?
Not entirely sure why you want to do what you have outlined
here but this works:
class Cfg:
pass
#config = Cfg()
def assign(config):
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
assign(config)
print config.Start
foo()
You should probably post what you are trying to do. Maybe we
can make a suggestion about the best approach.
-Larry Bates
--
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Re: Problem with exec
Antoon Pardon wrote:
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
When I execute this I get the following error:
Traceback (most recent call last):
File mod1.py, line 13, in ?
foo()
File mod1.py, line 10, in foo
exec assign() in dct
File string, line 1, in ?
File mod1.py, line 5, in assign
setattr(config, 'Start' , [13, 26, 29, 34])
NameError: global name 'config' is not defined
Now I don't understand this. In the documentation I read the following:
If only the first expression after in is specified, it should be a
dictionary, which will be used for both the global and the local
variables.
I provided a dictionary to be used for the global variables and it
contains a 'config' entry, so why doesn't this work?
If you have a module
v
def f(): return v
and call f in another module
print f()
where no global variable v is defined, would you expect that call to fail?
Of course not, but how can f look up the variable v then? The function
object keeps a reference of the global namespace it was defined in.
For your example that means the assign() function will look up the config
object in the module's globals(), not in the dictionary you provide to exec
One way to fix your problem would be to define the assign() function inside
the exec'd string.
Peter
--
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Parser or regex ?
Hello all, I'm writing a module that takes user input as strings and (effectively) translates them to function calls with arguments and keyword arguments.to pass a list I use a sort of 'list constructor' - so the syntax looks a bit like : checkname(arg1, arg 2, 'arg 3', keywarg=value, keywarg2='value2', default=list(val1, 'val2')) Worst case anyway :-) I can handle this with regular expressions but they are becoming truly horrible. I wonder if anyone has any suggestions on optimising them. I could hand write a parser - which would be more code, probably slower - but less error prone. (Regualr expressions are subject to obscure errors - especially the ones I create). The trouble is that I have to pull out the separate arguments, then pull apart the keyword arguments and the list keyword arguments. This makes it a 'multi-pass' task - and I wondered if there was a better way to do it. As I use ``findall`` to pull out all the arguments - so I also have to use a *very similar* regex to first check that there are no errors (as findall will just miss out badly formed parts of the input). My current approach is : pull out the checkname and *all* the arguments using : '(.+?)\((.*)\)' I then have : _paramstring = r''' (?: ( (?: [a-zA-Z_][a-zA-Z0-9_]*\s*=\s*list\( (?: \s* (?: (?:.*?)| # double quotes (?:'.*?')| # single quotes (?:[^',\s\)][^,\)]*?) # unquoted ) \s*,\s* )* (?: (?:.*?)| # double quotes (?:'.*?')| # single quotes (?:[^',\s\)][^,\)]*?) # unquoted )? # last one \) )| (?: (?:.*?)| # double quotes (?:'.*?')| # single quotes (?:[^',\s=][^,=]*?)| # unquoted (?: # keyword argument [a-zA-Z_][a-zA-Z0-9_]*\s*=\s* (?: (?:.*?)| # double quotes (?:'.*?')| # single quotes (?:[^',\s=][^,=]*?) # unquoted ) ) ) ) (?: (?:\s*,\s*)|(?:\s*$)# comma ) ) ''' I can use ``_paramstring`` with findall to pull out all the arguments. However - as I said, I first need to check that the entrie input is well formed. So I do a match against : _matchstring = '^%s*' % _paramstring Having done a match I can use findall and ``_paramstring`` to pull out *all* the parameters as a list - and go through each one checking if it is a single argument, keyword argument or list constructor. For keyword arguments and lists constructors I use another regular expression (the appropriate part of _paramstring basically) to pull out the values from that. Now this approach works - but it's hardly optimal (for some value of optimal). I wondered if anyone could suggest a better approach. All the best, Fuzzyman http://www.voidspace.org.uk/python/index.shtml -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with exec
Antoon Pardon wrote:
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
When I execute this I get the following error:
Traceback (most recent call last):
File mod1.py, line 13, in ?
foo()
File mod1.py, line 10, in foo
exec assign() in dct
File string, line 1, in ?
File mod1.py, line 5, in assign
setattr(config, 'Start' , [13, 26, 29, 34])
NameError: global name 'config' is not defined
Now I don't understand this.
I thought you were an expert?
Python's lexically scoped, not dynamically scoped. Using a specific
global context for the statement assign() doesn't mean that code
called by that statement will suddenly get the same global context.
/F
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Re: Python IDE
Martin Miller wrote: ... If someone with actual experience using Komodo with Python is listening, I'd be very interested in hearing what you think of it I got a copy of Komodo some time ago, and I love it. I wanted a fairly reliable debugging platform for a fairly large server I was building (the business crumbled nastily), and I wanted to step through the code to see where we were having problems. I have personally not had huge success using Idle for that (although it doesn't really seem problematic for smaller stuff), and I have been _very_ happy with Komodo. Getting the updates w/o extra charge was a bonus. I was happy with the deal on the original version, so these further improvements just make my deal feel better. I don't regularly use Komodo, but when I do want it, it is invaluable. My only affiliation with ActiveState is as a customer. --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with exec
Op 2005-12-16, Peter Otten schreef [EMAIL PROTECTED]:
Antoon Pardon wrote:
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
When I execute this I get the following error:
Traceback (most recent call last):
File mod1.py, line 13, in ?
foo()
File mod1.py, line 10, in foo
exec assign() in dct
File string, line 1, in ?
File mod1.py, line 5, in assign
setattr(config, 'Start' , [13, 26, 29, 34])
NameError: global name 'config' is not defined
Now I don't understand this. In the documentation I read the following:
If only the first expression after in is specified, it should be a
dictionary, which will be used for both the global and the local
variables.
I provided a dictionary to be used for the global variables and it
contains a 'config' entry, so why doesn't this work?
If you have a module
v = 42
def f(): return v
and call f in another module
print f()
where no global variable v is defined, would you expect that call to fail?
Of course not, but how can f look up the variable v then?
But I am not just calling. I'm using exec. And from the documentation
from exec I get the impression you can use it so that a function
will have temporarily a different reference to global namespace.
--
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Re: Which Python web framework is most like Ruby on Rails?
On Thu, 15 Dec 2005 20:15:17 -0800, Alex Martelli [EMAIL PROTECTED] wrote: If you claim there's a web project that's unfeasible to do in Ruby, you'd better come up with a strong example. If you're making no such claim, which would be counter to the claims of the Ruby community, then there aren't gonna be any web projects unfeasible with Rails, either. I believe Rails assumes you're using a relational database, not an object database like Durus or the ZODB. It seems to me Django is similarly focused; are there hooks that would allow replacing an RDBMS commit with a custom commit callback? --amk -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with exec
Op 2005-12-16, Larry Bates schreef [EMAIL PROTECTED]:
Antoon Pardon wrote:
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
[ ... ]
You should probably post what you are trying to do. Maybe we
can make a suggestion about the best approach.
I'm using PLY. The assign function is a dumbded down version
of a production function that will be called during the parsing
of a config file. Each time a line of the form:
var = val
is encounterd I do setattr(config, 'var', val)
The problem is that doing it this way means config needs to be global.
which I'm trying to avoid, in case some leftovers may cause trouble
when I read in a new configuration or should I ever have different
threads parsing files at the same time.
The other way would be passing the 'config' variable around in the
productions, but this would complicate things.
So what I am trying to do was provide a global namespace to the call
to fool a function using a global name into using a provided local name.
--
Antoon Pardon
--
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Re: Haskell Typeclasses
Kay Schluehr [EMAIL PROTECTED] wrote: ... work. Or maybe it works and I just have no clue how completely opaque call graphs as they appear in functions like this def f(x): h = g(x) h() can be tracked sufficiently in register-time in order to capture dependencies. It is not clear what h can be unless g is called and it might be as hard as type-inference or completely impossible to figure this out without executing g. If otherwise the checker can guarantee detection of a few obvious cycles where dependencies can be tracked also syntactically, at least in principle like in your example, what exactly is ensured by the checker and how can the definition of a typeclass be adapted accordingly? My preference would be to have the dependency tracker mark explicit dependencies only; here, if this was in a typeclass with the appropriate additions of self., I'd mark f as dependent on g only. No real purpose is served by allowing dependencies to be specified in a cloaked form, anyway -- nor in going out of one's way to impede vigorous attempts by a programmer to shoot himself or herself in the foot. Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: RoR like (was : SPE 0.8.1.b Python IDE...)
bruno at modulix wrote: Adrian, what you describe here is *exactly* what I call no Ajax support: you have to handle the whole thing manually, the framework doesn't provide anything by itself. Would you say the CGI module offers support for templating, data persistance and Ajax as well ?-) Hey Bruno, Sorry for the misunderstanding. Here's the Django code I use on the Ajax bit of the chicagocrime.org Find your District page (http://www.chicagocrime.org/districts/). See the Guess district button on that page. def rpc_guess_district(request, longitude, latitude): try: b = beats.guess_by_coordinates(float(longitude), float(latitude)) except beats.BeatDoesNotExist: return HttpResponse(Looks like you're not centered on a point in Chicago. + \ Please move the map to Chicago and try again.) return HttpResponse(You're centered on %s % b.get_name_and_district()) My point is, you don't need a huge serialization framework to do Ajax easily. As long as a server can return snippets of code (or even plain text), you can do it. These pages work the same way: http://www.chicagocrime.org/map/ http://www.chicagocrime.org/wards/ http://www.chicagocrime.org/route/ Hope that clears up my point of view, Adrian -- http://mail.python.org/mailman/listinfo/python-list
How to use pydoc?
import pydoc import sys sys.version '2.4.2 (#67, Sep 28 2005, 12:41:11) [MSC v.1310 32 bit (Intel)]' pydoc sys SyntaxError: invalid syntax The documentation for pydoc says: Run pydoc name to show documentation on something. What am I missing? Thanks! Chris -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Without downloading and installing your code, can you tell me what the
result of these comparisons would be?
col = Enum('red', 'green', 'blue')
day = Enum('mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun')
col.blue == blue
day.tue == 23
If they return False I would expect
col.blue == day.tue
to return False as well, not raise an exception.
Skip
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Re: Python IDE (was: PythonWin troubleshooting)
chuck [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Apparently not too many people use or are interested in PythonWin. I'm giving up on it. It used to work pretty good. I'm lucky that I have found PyScripter (http://www.mmm-experts.com/) a python IDE for the windows platform which is much more stable and has more features that PythonWin. If you are doing Python development on Windows I'd recommend taking a look at it. I'm also evaluating Wing IDE. I may have another post with comments on it for anyone who might be interested. Here's a plug for SPE, since I haven't heard anyone extolling its virtues. I use it every day and love it. --Tim -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem with exec
Antoon Pardon wrote: And from the documentation from exec I get the impression you can use it so that a function will have temporarily a different reference to global namespace. That impression confuses two things: (1) A function object carries a global namespace with it. That namespace is fixed when the function definition is executed, not when the function is called. (2) You may provide a global namespace to exec. What's in that may be altered by rebinding operations (=, def, etc.) in the exec't string. Functions defined here use that namespace as their global namespace while functions just executed here don't. If you could provide a function with a different namespace when it's called, e. g f() in namespace would look up its globals in namespace, that might be an interesting concept but it's not how Python works. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Parser or regex ?
Fuzzyman [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Hello all, I'm writing a module that takes user input as strings and (effectively) translates them to function calls with arguments and keyword arguments.to pass a list I use a sort of 'list constructor' - so the syntax looks a bit like : checkname(arg1, arg 2, 'arg 3', keywarg=value, keywarg2='value2', default=list(val1, 'val2')) Worst case anyway :-) pyparsing is great, easy to configure and very powerful--I think it looks like a great tool for your inputs. http://pyparsing.sourceforge.net/ --Tim -- http://mail.python.org/mailman/listinfo/python-list
Re: to write set of values to a file from python
[EMAIL PROTECTED] wrote:
hi
thanks every body for the help.
Now how can check whtr the row am reading is the last row or not??
for example: ...
reader = csv.reader(file)
for row in reader:
print row
HERE HOW CAN I CHECK WHTR THIS ROW IS THE LAST ONE IN THE FILE
so that if at all i dint find what am searching for i can write that
information at the last row, after opening the file in a append mode.
What Steve Holden says is right. If it turns out you need to know
ahead of time, use a lagged input to determine whether it is last:
def lagged(source):
'''produce element,islast for elements in source'''
generator = iter(source)
previous = generator.next()
for element in generator:
yield previous, False
yield previous, True
file = open ('C:\some.csv','r')
reader = csv.reader(file)
for row, final in lagged(reader):
print row
if final:
print 'final:', row
else:
print 'leads:', row
--Scott David Daniels
[EMAIL PROTECTED]
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Re: Problem with exec
Antoon Pardon wrote:
Op 2005-12-16, Larry Bates schreef [EMAIL PROTECTED]:
Antoon Pardon wrote:
I have the following little piece of code:
class Cfg:pass
#config = Cfg()
def assign():
setattr(config, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
dct = {'config':config, 'assign':assign}
exec assign() in dct
print config.Start
foo()
[ ... ]
You should probably post what you are trying to do. Maybe we
can make a suggestion about the best approach.
I'm using PLY. The assign function is a dumbded down version
of a production function that will be called during the parsing
of a config file. Each time a line of the form:
var = val
is encounterd I do setattr(config, 'var', val)
The problem is that doing it this way means config needs to be global.
which I'm trying to avoid, in case some leftovers may cause trouble
when I read in a new configuration or should I ever have different
threads parsing files at the same time.
The other way would be passing the 'config' variable around in the
productions, but this would complicate things.
So what I am trying to do was provide a global namespace to the call
to fool a function using a global name into using a provided local name.
Maybe you could use a bound method?
class Cfg:
def assign(self):
setattr(self, 'Start' , [13, 26, 29, 34])
def foo():
config = Cfg()
namespace = dict(assign=config.assign)
exec assign() in namespace
print config.Start
Peter
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Re: Enumeration idioms: Values from different enumerations
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
Ben What should be the result of this comparison::
ShirtSize.small == AppleSize.small
False. They are values from different objects. Just make __eq__ map to
is. I think you'll be fine.
Ben Or is it an error to even try comparing them?
As someone else pointed out containment tests become difficult with your
current formulation.
Do any python builtins behave that way? How about anything in the
python standard library?
Ben No to both; I believe this may be a defining property of
Ben enumerations. Am I wrong?
I think so. 0.5 wink. I think you should be able to compare any two
objects. I think the complex types give you a little wiggle room on the
size comparisons (, =, , =), but I think == and != really ought to work.
Skip
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Re: access to preallocated block of memory?
You might want to take a look at the Blocks and Views code I did, take a look at it and see if you can either use it directly or use it with any changes you feel like making. http://members.dsl-only.net/~daniels/Block.html -- -Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Which Python web framework is most like Ruby on Rails?
Mike Meyer wrote: Ben Sizer [EMAIL PROTECTED] writes: Flexibility is good, but personally I think the problem is that instead of useful variety, we have redundant overlap. How many different templating systems, sql--object mappings, and URL dispatch schemes do we need? And what exactly is the difference between them all, except for slightly different syntax? Well, they come in at least three major variants: complete publishing system (ake zope), templating system (aka psp), and modules (aka cgi). Each of these is focused on a different level of the problem, and hence is suitable for different things. I see what you mean, but unfortunately I think there is a lot more fuzziness than that. If the separate parts were clearly delineated things would be a lot better. I look to the Database API Specification as a great example of how this could (should?) be done, allowing for easy interchangeability while still providing a well-documented standard, and the opportunity to bundle a basic module with the standard library without raising the difficulty level for those who wish to use other frameworks. A PyWebForm API and a PyWebSession API would be fairly easy to create, for example. Templating maybe less so, but not much. Syntax can be very important, especially for templating systems. Typically, those are used in situations where you have a lot of X/HTML and want a bit of dynamic content. Ideally, you want to be able to treat this just like a static HTML page. If the syntax of a templating system makes your standard web tools puke, you probably want to avoid it. I think templating syntax is very important, but with something like Python I think the future is in modules like HTMLTemplate rather than the ASP/PHP model. When you're working with a valid XML page in the first place, all your tools should work adequately. -- Ben Sizer -- http://mail.python.org/mailman/listinfo/python-list
Re: How to use pydoc?
[EMAIL PROTECTED] wrote: import pydoc import sys sys.version '2.4.2 (#67, Sep 28 2005, 12:41:11) [MSC v.1310 32 bit (Intel)]' pydoc sys SyntaxError: invalid syntax The documentation for pydoc says: Run pydoc name to show documentation on something. What am I missing? In the interpreter, just do help(sys) or help(sys) if you didn't already import the module. What you tried is what you would do on the command line. I'm not sure it works on windows, though, but python -m pydoc sys Should work on both windows and unix. Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Parser or regex ?
Tim Arnold wrote: Fuzzyman [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Hello all, I'm writing a module that takes user input as strings and (effectively) translates them to function calls with arguments and keyword arguments.to pass a list I use a sort of 'list constructor' - so the syntax looks a bit like : checkname(arg1, arg 2, 'arg 3', keywarg=value, keywarg2='value2', default=list(val1, 'val2')) Worst case anyway :-) pyparsing is great, easy to configure and very powerful--I think it looks like a great tool for your inputs. Thanks - I considered it. It's actually quite a small module (about 38k). I don't want to introduce a dependency on an external module. All the best, Fuzzyman http://www.voidspace.org.uk/python/index.shtml http://pyparsing.sourceforge.net/ --Tim -- http://mail.python.org/mailman/listinfo/python-list
Invoking Unix commands from a Python app
Hi all, An idea popped into my head recently for an app that would track how much time a user spends in a particular piece of software (or at least, for how long an application is open). I'm assuming there is a way to do this via the command line and a unix app, although I haven't yet invesitgated it. My question is, can a command line application be invoked by a python program? If so, how does one pass parameters to it and retrieve its response? Cheers and Merry Christmas, Rob Cowie -- http://mail.python.org/mailman/listinfo/python-list
Re: problem with os.spawnle(os.P_NOWAIT,'C:\info.exe')
Ya Thanks Fredrik, i had overwritten the os in my code indeed, now its working fine. thanks a lot for that regards -- http://mail.python.org/mailman/listinfo/python-list
SMP, GIL and Threads
Hi, I have an app written under version Python 2.3.5. The problem I'm having is that it hangs on one of its threads. The thread that hangs does updates to a standard dictionary shared with another thread that only reads this dictionary. This app works beautifully on a single processor boxes in my testing environment, but this problem quickly occurs when the software runs on a dual cpu SMP blade server with hyperthreading turned off, Windows 2003 server. I do not bother using application level locks because I figure the GIL is going to do the job for me, and because with one thread doing updates and the other only reading, things remain consistent logically for the app. The app will not have a problem if the dictionary changes just before it does a read. I have searched this group on this subject and seen one warning against sharing objects between threads. I don't recall every writing a threaded app that didn't share data between threads in some way. I've also seen a recomendation in this list against using threads at all with Python. I'm hoping that is an extreme view and not general wisdom here. Python has never failed me when analysis indicated that it would be the correct tool for the job. Thank you for your time and attention. Randy -- http://mail.python.org/mailman/listinfo/python-list
Re: Enumeration idioms: Values from different enumerations
Ben Finney [EMAIL PROTECTED] writes:
Mike Meyer [EMAIL PROTECTED] writes:
Peter Hansen [EMAIL PROTECTED] writes:
That is, [perhaps] trying to compare enumerations that should not
be compared *is* an error (raising an exception) *because* the
whole point of enumerations is to avoid errors in such cases.
Except it might not be an error. For instance, if I've got a list of
enum objects taken from various types (say I've got one set of enums
for days of the week, another for months of the year, and so on, and
which I use depends on whether the user wants to select days of the
week, months of the year, etc), it makes perfect sense to want to know
if a specific enum value is in the list, and the obvious way to check
it is with my_value in enum_list. That won't work if you raise an
exception - it takes a relatively convoluted bit of code to make this
test.
What's being discussed here is what happens when comparing the *values*
from the enumeration.
That's what I thought I was discussing, but apparently I wasn't clear
enough. Let me try again.
I think it's perfectly reasonable to store enum values from different
enums in a list, and check for a specific value being in that list. If
comparing two enum values can raise an exception, then doinng this
become problematic, as you may get an exception. According to what you
say below, this isn't true for any builtin type or any type in the
standard library.
Python generally uses '==' to mean is the same value. To do that,
a simple true/false return is enough. In raising an exception,
you're making '==' carry an extra meaning (I'm not sure *what* that
is, though).
The problem with is the same value as an explanation for '==' is
that it doesn't help in cases such as::
ShirtSize = Enum('small', 'medium', 'large')
AppleSize = Enum('small', 'large')
Actually, it provides a very explicit guideline for these cases. The
guidelines is by no means obvious, as witness languages like LISP,
which have multiple equality operators.
What should be the result of this comparison::
ShirtSize.small == AppleSize.small
Are they the same value? They're both small (and they both coerce
to the same string value, and in this case the same integer value).
That depends on the semantics you want to place on the values of
enums. Reasonable arguments can be made for anything from they're
exactly like small integers to the values are an implementation
detail, and you shouldn't worry about them. That they coerce to the
same string is irreleevant, at least in python, which doesn't coerce
strings to
Do any python builtins behave that way? How about anything in the
python standard library?
No to both; I believe this may be a defining property of
enumerations. Am I wrong?
There are enum implementations that don't treat comparing enum values
from different enums as an error, so I'd say you're wrong. In Python's
case, comparing two objects for identity never raises an exception for
any type that comes with the language, so I'd say that that was a
defining property of python.
mike
--
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Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
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Re: Invoking Unix commands from a Python app
Rob Cowie enlightened us with: Ok, I know see that os.spawnl() will suffice. However, how do I retrieve the output of the command. Apparently, os.spawnl() didn't suffice. Check out the popen2 module and Popen* classes. Sybren -- The problem with the world is stupidity. Not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself? Frank Zappa -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding methods to instances
To avoid that: - subclass Test first class SubclassTest(T): pass - assign the method to SubclassTest's attribute, SubclassTest.dynamic = dynamic - then assign the new class to magic variable __class__ : t.__class__ = SubclassTest t.dynamic() Antoon Pardon wrote: But this will make the function a method to all instances of the class. Is that what you want? From your first post I had the impression you only wanted the function to be the method of one particular instance. -- http://mail.python.org/mailman/listinfo/python-list
Re: Visual Python : finished ?
Do Re Mi chel La Si Do wrote: Hi! See : http://www.activeperl.com/Products/Visual_Perl/?mp=1 @+ MCI Another closed source success story. -- http://mail.python.org/mailman/listinfo/python-list
Re: Adding methods to instances
Antoon Pardon [EMAIL PROTECTED] wrote: Op 2005-12-15, Ed Leafe schreef [EMAIL PROTECTED]: On Dec 15, 2005, at 11:51 AM, Lawrence Oluyede wrote: So? Am I nuts? Or is this possible? Yes it is, use exec() to turn your string in valid Python code and bind the dynamic function as a method of class Test xx = def dynamic(self): print dynamic, self.testAtt exec xx class Test(object): testAtt = sample def normalMethod(self): print normal, self.testAtt t = Test() Test.dynamic = dynamic t.dynamic() Thanks! I knew I had done this before. My mistake was that I was setting the exec'd code to the instance, and not to the class. That works, but makes it a function, which doesn't automatically get sent the 'self' reference. But this will make the function a method to all instances of the class. Is that what you want? From your first post I had the impression you only wanted the function to be the method of one particular instance. How about: def bind(fun, arg): return lambda *a, **k: fun(arg, *a, **k) t.dynamic = bind(dynamic, t) -- Ben Hutchings The world is coming to an end. Please log off. -- http://mail.python.org/mailman/listinfo/python-list
Re: Invoking Unix commands from a Python app
Excellent... just the thing I was looking for. Thanks. Does anyone know of a unix app that could be used to monitor the duration of processes etc.? Would 'top' do the trick? Rob C -- http://mail.python.org/mailman/listinfo/python-list
Re: Parser or regex ?
Fuzzyman wrote:
Hello all,
I'm writing a module that takes user input as strings and (effectively)
translates them to function calls with arguments and keyword
arguments.to pass a list I use a sort of 'list constructor' - so the
syntax looks a bit like :
checkname(arg1, arg 2, 'arg 3', keywarg=value,
keywarg2='value2', default=list(val1, 'val2'))
Worst case anyway :-)
...
Perhaps you could simply use Python's parser - the syntax appears to be
Python's.
e.g., a very quick hack using eval, which is easier without the list call, so
I'm cheating and replacing it with a list literal for now:
source = checkname(arg1, arg 2, 'arg 3', keywarg=value,
... keywarg2='value2', default=[val1, 'val2'])
We need some way to ensure bare names don't cause NameErrors:
class lazynames(dict):
... def __getitem__(self, key):
... if key in self:
... return dict.__getitem__(self, key)
... return %s % key # if name not found, return it as a str constant
...
def checkname(*args, **kw):
... return args, kw
...
d = lazynames(__builtins__ = None, checkname = checkname)
With this set up, you can parse in one line!
eval(source, globals(), d)
(('arg1', 'arg 2', 'arg 3'), {'default': ['val1', 'val2'], 'keywarg':
'value',
'keywarg2': 'value2'})
If you don't like the risks of eval, then compiler.parse gives a form of the
parse output that is fairly easy to deal with
Cheers
Michael
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Re: SVG rendering with Python
On Fri, Dec 16, 2005 at 01:58:40PM +1100, richard wrote: Andreas Lobinger wrote: richard wrote: Dennis Benzinger wrote: Does anybody know of a SVG rendering library for Python? Google python svg ... to find what? The answer to the OP's question. The OP's question is ambiguous. Does he want to render something to SVG? or does he want to render an existing SVG file to a raster format. I would guess the latter, apparently you think he means the former. Luckily for the OP we both posted an answer for what we thought he was asking so he will have an answer either way :) Richard -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
