Re: PEP 354: Enumerations in Python
On Monday 27 February 2006 02:49, Ben Finney wrote:
Coercing a value from an enumeration to a ``str`` results in the
string that was specified for that value when constructing the
enumeration::
That sentence seems to assume that all enumeration values will have been
specified as strings. Thats reasonable, but your description of the creation
of an enumeration doesnt specify that.
An enumerated type is created from a sequence of arguments to the
type's constructor::
Weekdays = enum('sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat')
Grades = enum('A', 'B', 'C', 'D', 'F')
s/arguments/strings/
?
--
Toby Dickenson
--
http://mail.python.org/mailman/listinfo/python-list
Re: Using graphviz to visualize trace.py output, anybody?
Maybe there is some other tool that I am not aware of which can create this kind of trace. I use eclipse with pydev plugin on MacOS 10.3.9 kcachegrind http://kcachegrind.sourceforge.net/cgi-bin/show.cgi -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: Sorting with only a partial order definition
On Thursday 27 October 2005 11:08, Lasse Vågsæther Karlsen wrote: What I was wondering about is if there is an algorithm that would do what I want? Ie. help me pick the nodes so as to minimize the number of edges. To rephrase your question, you want a sorting algorithm that minimises the number of comparisons (because a comparison involves asking a human), and which takes advantage of any pre-existing rough ordering. You need timsort - the algorithm behind python lists sort() method. -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: Would there be support for a more general cmp/__cmp__
On Thursday 20 October 2005 11:53, Steve Holden wrote: Personally I'm still not convinced that your requirement reflects a substantial use case (but then I'm getting used to that ;-). Just because an ordering is partial that doesn't mean that two instances of a class shouldn't be compared. C++ has a cmp template function which can be implemented to define a total ordering for one type. This can be reliably used by implementations of ordered tree containers (for example) so that this container template class can only be instantiated for holding types that provide this comparison template function. One disadvantage is that these template container classes can only hold one type. ZODB's BTrees work in a similar way but use the regular python comparison function, and the lack of a guarantee of a total ordering can be a liability. Described here in 2002, but I think same is true today: http://mail.zope.org/pipermail/zodb-dev/2002-February/002304.html A BTree might contain two objects that are incomparable. That is, they raise an exception when compared. However the user will not know this if by coincidence the BTree implementation has never needed to compare these two objects. Now removing a third object from the container such that these two incomparable objects are adjacent in the BTree. There is a possibility that an exception might be raised when *reading* content from the BTree, since the BTree implementation now might need to compare this pair of objects. What would you have Python do when the programmer tries to perform an invalid comparison (i.e. what are the exact semantics imposed when __cmp__() returns None/raises an exception)? Its too late to handle this by the time a specific comparison method of an individual object is being called. If you need a total ordering across a domain of objects then you need to involve some representation of that domain as a whole. -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: [path-PEP] Path inherits from basestring again
On Wednesday 27 July 2005 05:37, Meyer, Tony wrote: I can see that this would make sense in some situations, but ISTM that it would make a great deal more sense (and be much more intuitive) to have concatenation include the separator character (i.e. be join). def functions_which_modifies_some_file_in_place(path): output = open(path+'.tmp', 'w') . I dont want a seperator inserted between path and the new extension. -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: System Independent Wallpaper Changer
On Wednesday 06 July 2005 01:12, Terrance N. Phillip wrote: I've done some searching, and can't seem to find a programatic way of getting *** that to happen. http://www.google.com/search?q=setwallpaper+dcop I hope this helps -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: asynchronous comunication, wxPython and threads.
On Tuesday 21 June 2005 14:22, Zunbeltz Izaola wrote: This comunication is done in a new thread not to frezee the GUI. The problem is that when Stop is done (it kills the thread) some confirmation sockets are mixed (are not receibed in the correct order although i use tcp). I guess you are accessing the socket from both your GUI thread and communications thread. Dont do that. An action in the GUI thread should signal the communictions thread, then the communictions thread talks to the socket. I have been told not to do comunication in a new thread; instead, I should use asyncronus comunication. Using non-blocking sockets in the GUI thread may cause the opposite problem to the one that led you to use threads in the first place: a blocking operation in the GUI may freeze the communications. Maybe that isnt a problem for you. If it is, I suggest sticking to two threads. What module should i use, asyncore, asynchat, twisted,(anohter) If you are talking to only one device, then using blocking sockets is a good approach. However Ive never written an application like this that didnt need to support a second (or third) machine sooner or later, and three communictions threads is starting to get ugly. A framework like Twisted will let you handle many machines in the one thread, but it still makes sense to keep a second one for the GUI. -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: collect data using threads
On Tuesday 14 June 2005 17:47, Peter Hansen wrote: Kent Johnson wrote: Peter Hansen wrote: That will not work, and you will get data loss, as Jeremy points out. Can you explain why not? self.data is still bound to the same list as x. At least if the execution sequence is x = self.data self.data.append(a_piece_of_data) self.data = [] Ah, since the entire list is being returned, you appear to be correct. Interesting... this means the OP's code is actually appending things to a list, over and over (presumably), then returning a reference to that list and rebinding the internal variable to a new list. If another thread calls on_received() and causes new data to be appended to the list between those two statements, then it will show up in the returned list (rather magically, at least to my way of looking at it) and will not in fact be lost. But it might not show up until too late. The consumer thread that called get_data presumably does something with that list, such as iterating over its contents. It might only show up after that iteration has finished, when the consumer has discarded its reference to the shared list. -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Impact Analysis Tool ?
On Thursday 26 May 2005 13:46, [EMAIL PROTECTED] wrote: Hi I am a mainframe designer/progrmmer. What I need is a tool that shows me at design time what links to what so that I can understand the application. When a design change comes through I could say OK this change affects only A, B, and C out of the whole alphanet. Then I would be able to isolate what needs to be changed and unit tested..I am trying to improve programmer productivity at design time. For physical dependencies between modules: http://www.tarind.com/depgraph.html -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows distribution suggestions?
On Tuesday 17 May 2005 09:35, Timothy Smith wrote: mate dont bugger around with all that. py2exe will make you a windows native exe to run. and for updates you just need to update it's library.zip. py2exe is working great for me too. My app contains three different programs (say alice.py, bob.py, and carol.py) that need to be independently launchable, and a dozen or so other .py files that get imported into those first three One tip: make sure your three top-level scripts are as empty as possible: just import some other module and call a function. All your active code is then in some library.zip shared between the three, and you need never change alice.exe, bob.exe, and carol.exe use NSIS for the installer, it can do anything you want an it's free. it couldn't be more simple, shoot me an email if you need more Ive not used NSIS, but I have had good results from the free WiX tools, at http://sourceforge.net/projects/wix/. Documentation is poor, but examples are plenty. -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: Distributing applications
On Wednesday 02 March 2005 14:12, Phillip Mills wrote: now any comments or references on the mechanics of creating a self-contained distribution? Run to http://starship.python.net/crew/theller/py2exe/ -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: Flow chart (function tree) cross references
On Tuesday 22 February 2005 13:27, qwweeeit wrote: Does someone knows something about function tree generation and cross references? for trees of *module* dependencies: http://www.tarind.com/depgraph.html -- Toby Dickenson -- http://mail.python.org/mailman/listinfo/python-list
Re: python connect to server using SSH protocol
On Tuesday 08 February 2005 13:26, Simon Anders wrote:
This is what I was about to reply as well. But I did a short test
program and encountered a problem:
import os
fi, foe = os.popen4 ('ssh dopey')
print fi, 'ls'
fi.close () # -- this is annoying
for line in foe:
print line,
foe.close ()
The above connects to a server, passes the command 'ls', which is
executed there, and prints the returned result.
However, reading from foe succeeds only if fin has been closed before.
An fi.flush() seems to be not sufficient.
But this version below does work. Im not sure whats happening when using the
file as an iterator to make a difference.
import os, sys
fi, foe = os.popen4 ('ssh x')
print fi, 'ls'
fi.flush () # -- this is annoying
while 1:
b = foe.readline()
sys.stdout.write(b)
But if one wants Python to
interactivly communicate with some shell on a remote machine, it is
inconvenient to have to close and reopen the connection all the time.
But this route carries a big deadlock risk. the rsync program can tunnel over
ssh this way, but have first hand experience of
http://www.google.com/search?q=rsync+ssh+deadlock
In the script above, if 'ls' is replaced with a longer input then there is
every chance that the fi stream will block before all of it is written,
because this script hasnt started draining foe.
For a real python program using ssh (but not 'interactive'... data written to
fi does not depend on data read from foe) see
http://dirstorage.sourceforge.net/replica.html
--
Toby Dickenson
--
http://mail.python.org/mailman/listinfo/python-list
