Re: [Info] PEP 308 accepted - new conditional expressions

[Leif K-Brooks]

Sam wrote:
> And "foo if bar" is Perl-ish; yet, even Perl has the ? : operators.

What _isn't_ Perl-ish?
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Re: what does 0 mean in MyApp(0)

[vincent wehren]

"Alex" <[EMAIL PROTECTED]> schrieb im Newsbeitrag 
news:[EMAIL PROTECTED]
| Thanks for the replies. It seems that I have three options
| 1. app=MyApp()
| 2. app=MyApp(0)
| 3. app=MyApp('myfile.txt')
|
| 1. In the first case the output stream will be set to stdout/stderr,
| which means that errors will be sent to a window which will be closed
| when the app crashes.
| 2. In the second case the output will be set to the command prompt
| window, which means that I will be able to catch the errors when my app
| crashes.
| 3. There is also a third alternative which is to set the output to  a
| file.
|
| Alterbnative 2 is simple and useful, so that's why everybody use that
| alternative.
|
| Is that correct?

Not entirely:

1. app=MyApp(): stdout/stderr is redirected to its own window, so you're
right here
2. app=MyApp(0): stdout/stderr is not redirected to a window.
Tracebacks will show up at  the console. So you're right here to...

But:
3(a). app=MyApp(1, 'some/file/name.txt'):
   stdout/stderr is redirected to to the file 'some/file/name.txt').

The arguments you pass to MyApp are named parameters, so for improved
readability you may want to use:

3(b). app=MyApp(redirect=1, filename='some/file/name'): will redirect stdout
  to 'filespec'

and instead of 2:

2(b). app=MyApp(redirect=0) # stdout/stderr will stay at the console...

Anyway, if you omit the parameter names, make sure you you position them 
correctly, i.e., a filename should only be positioned as /second/ argument.

HTH,
--

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| Alex
| 


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Re: Will python never intend to support private, protected and public?

[Paul Rubin]

Mike Meyer <[EMAIL PROTECTED]> writes:
> Unless your compiler detects and flags passing private variables to
> external functions all you've got is a convention that you don't pass
> private variables to external functions.

Yes, the point is that it's something that you can check for by
examining the class in question without having to examine any other
classes.

> Are you going to try and tell me thas using builtin functions on
> private variables is something you don't allow in your projects?

You have to treat builtin functions as part of the language.  Of
course Python has this situation where someone could rebind the name
"len" to some other function, so you have to deal with that too, maybe
just at the file scope.  An OOP approach (lst.len() instead of
len(lst)) that binds the builtin names to datatypes might be
preferable in some situations but I'll leave that one for the
theorists.

> Of course, there's nothing wrong with catching errors earlier. Might I
> suggest that you file a change request for pylint (or your favorite
> error checker) asking that it start issuing warnings for
> object._variable?

I don't see how pylint could know which instances to flag, without
doing type inference on all the objects to know that the variable
belonged to an instance of some other class.
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Not defined

[Rob]

When trying the basic tutorial for cgkit I always seem to get a not defined 
error as follows.

Pythonwin GUI

>>> from cgkit import *
>>> Sphere()
Traceback (most recent call last):
  File "", line 1, in ?
NameError: name 'Sphere' is not defined
>>> b=Box(name="Cube", pos=(1.5,2,0))
Traceback (most recent call last):
  File "", line 1, in ?
NameError: name 'Box' is not defined
>>>

I am useing  ver 2.4

A little help would be most appreciated.

Forgive me please if this is not the proper place for this ?  I am trying to 
keep an active brain :)

Regards Gramps



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Re: A Moronicity of Guido van Rossum

[Gerrit Holl]

Tony Meyer wrote:
> X-Spambayes-Classification: ham; 0.008
> 
> On 30/09/2005, at 10:56 PM, Gerrit Holl wrote:
> > Tony Meyer wrote:
> >> X-Spambayes-Classification: ham; 0.048
> 
> Unless I'm misreading things, that's *my* message that scored 0.048  
> (the "from:addr:ihug.co.nz", "from:name:tony meyer", and "spambayes"  
> tokens make it seem that way)...

It is, and that's very surprising, but apparantly it was not really
hammy enough. But don't worry, by ham_cutoff is 0.2, and out of the 10
'unsure' messages per week, 2 are spam, 2 are ham, and 6 are, well,
unsure. Note that with all my mailinglists, the number of messages
handled is more than 2500 per week, so I'm very, very happy with
spambayes...

Gerrit.

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-- 
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Re: Will python never intend to support private, protected and public?

[Paul Rubin]

Steven D'Aprano <[EMAIL PROTECTED]> writes:
> A cautionary tale of what happens when religious wars enter programming
> debates. For all I know, Paul Rubin is intelligent, gentle, kind to
> animals and small children, generous, charitable and modest.

Don't bet on it.

> But touch his religious belief in the necessity of "truly" private
> variables, and boy oh boy does he lose the plot.

I haven't claimed necessity (except in some specific types of
applications).  I've said it's a useful feature in a certain type of
development process.  So I think you're the one losing the plot and
acting like a religious whacko.  If there's a feature you don't want
to use, nobody is making you use it.  You're going off the deep end
saying nobody else should be allowed to use it either.

> Paul misses the point: in a language like Python that allows the dynamic
> modification of public methods (as well as private ones) you can't be
> sure with absolute 100% mathematical certainty that your public interface
> is the same at runtime as it was when you did your last code audit.

Obviously any privacy-enforcement mechanism has to cope with that.
Think of the situation with Bastion, back when it existed and was
believed to sort-of work.

> If your development team uses test-driven development, you will catch this
> breakage immediately you check the code in. If you don't, you've got
> lots more bugs that you don't know about, so one more is no big deal.

Methinks you have too much faith in testing.  It only shows that your
program handles the test cases that you give it.  To show that the
program handles all the other cases, you need actual logic.

> > Why on earth would you want to unnecessarily introduce random bugs
> > into a word processor or anything else?  
> 
> Paul puts words into my mouth: I never suggested that it was good to
> introduce bugs, unnecessarily or otherwise. What I said was that aiming
> for 100% mathematical certainty that there are no bugs in a word processor
> is pointless. No lives are at stake. The fate of nations doesn't rest on
> your ability to make sure that PyWord is 100% bug free. Relax dude, the
> world won't end if there is a bug or two in your code.

See:  http://vowe.net/archives/005838.html  
(found with about 5 seconds of Google searching).

People could very well have died over disclosures like that, whether
caused by software bugs or (as in this instance) by unlucky
interaction of intentional features.  These things happen over and over.  

If you look at the NSA's initial release of the Skipjack algorithm
spec, it was a PDF file containing a bitmap that was obviously a scan
of a fax of a document that had come out of a word processing program.
People chuckled that a mighty operation like the NSA could be so
technologically backward that they couldn't just put the word
processor file directly online.  Later they realized that maybe the
NSA was simply being careful, that the document had been prepared in a
classified environment and they didn't trust their word procssing
software to not leak classified info into the file, so they stuck to a
policy of only moving data like that around on paper and not in
computer files.

Information leakage from word processors is a serious problem.

> Of course, if Paul had been paying attention, he would have realised that
> 100% certainty is not possible in general no matter what style of
> development you use. Perhaps folks have heard of the halting problem?

You don't know what you're talking about.  That is a red herring.

> You can reduce the probability of bugs by using best practices, but never
> reduce it to zero. How small do you need? Is it really shocking to suggest
> that while a one in a billion billion chance of a bug might be
> needed for a nuclear reactor, we might be satisfied with just one in a
> million for a word processor?

In some ways, word processors are harder to write safely than nuclear
reactor code.  Nuclear reactors usually run in carefully controlled
environments and the field is mature enough that you can have some
reasonable confidence that the data going into the program (e.g. from
sensors) will be similar to the data that you tested the program with.
What you're left with is Murphy's Law: something unexpected could
happen by accident and you can make some reasonable assumptions about
the distribution of inputs to make sure the probability is low.  Ross
Anderson calls this "programming Murphy's computer".

A word processor, on the other hand, has to deal with malicious input,
that can be fiendishly crafted in ways that the implementer never
dreamed of.  It's the difference between worrying about being hit by a
meteor at random, and worrying about being hit by a meteor because
someone in the asteroid belt is steering them towards you on purpose.
Anderson calls this "programming Satan's computer".

> Should we decide that C is not suitable for critical applications?

Yes, absolutely.  C (by which term I include C++) is un

Recursive Property of Octal Numbers

[James Stroud]

I'm very curious about what is going on here. I'm sure my curiosity has 
something to do with ignorance of some fundamental concept of computer 
science (maybe that 8 is just a vertical infinity?):

py> b = '\xb6'
py> b[0]
'\xb6'
py> b[0][0]
'\xb6'
py> b[0][0][0]
'\xb6'
py> b[0][0][0][0]
'\xb6'
py> b[0][0][0][0][0]
'\xb6'



James

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UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/
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Re: Recursive Property of Octal Numbers

[PoD]

On Fri, 30 Sep 2005 15:40:51 -0700, James Stroud wrote:

> I'm very curious about what is going on here. I'm sure my curiosity has 
> something to do with ignorance of some fundamental concept of computer 
> science (maybe that 8 is just a vertical infinity?):
> 
> py> b = '\xb6'
> py> b[0]
> '\xb6'
> py> b[0][0]
> '\xb6'
> py> b[0][0][0]
> '\xb6'
> py> b[0][0][0][0]
> '\xb6'
> py> b[0][0][0][0][0]
> '\xb6'
> 
> 
> 
> James

b is a 1 character string.
b[0] is a one character string which is the first character of b.
Therefore b[0] == b.

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Re: Google Not Universal Panacea [was: Re: Where to find python c-sources]

[Steve Holden]

Erik Max Francis wrote:
> Steve Holden wrote:
> 
> 
>>While a snappish "go and look it up on Google" might suffice for a 
>>mouthy apprentice who's just asked their thirteenth question in the last 
>>half hour, it's (shall we say) a little on the brusque side for someone 
>>who only appears on the group last February, and has a history of asking 
>>reasonably pertinent though sometimes beginner-level questions.
> 
> 
> I told him exactly where it was.  I just also pointed out that he could 
> have trivially found out the answer on his own by using Google for 
> fifteen seconds.  It would be one thing if I (and nobody else) answered 
> his question and just rudely pointed him to Google.  But since I 
> actually answered his question, looks to me like someone just wanted to 
> stand on his soapbox today.
> 
I don't think "The source tarball on python.org" could claim to be 
telling him "exactly where it was" given that my copy of the web site 
has 341 MB of stuff in it.

Just that same, if you are saying that your behaviour didn't really 
merit my response then I'd probably agree. Your post was the straw that 
broke the camel's back rather than an egregious example of bad manners. 
So I'm sorry if it looked as though the soapboxing was directed 
primarily at you, which it wasn't.

regards
  Steve
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PyCon TX 2006  www.python.org/pycon/

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Re: Recursive Property of Octal Numbers

[Paul Rubin]

James Stroud <[EMAIL PROTECTED]> writes:
> I'm very curious about what is going on here. I'm sure my curiosity has 
> something to do with ignorance of some fundamental concept of computer 
> science (maybe that 8 is just a vertical infinity?):

Python doesn't have a character type.  A character is just a string of
length 1.  So 'a'[0] is the same as 'a'.  Thus 'a'[0][0][0]...[0] is
also the same as 'a'.
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Re: Google Not Universal Panacea [was: Re: Where to find python c-sources]

[Erik Max Francis]

Steve Holden wrote:

> I don't think "The source tarball on python.org" could claim to be 
> telling him "exactly where it was" given that my copy of the web site 
> has 341 MB of stuff in it.

He doesn't have to search through the whole thing, there's a link on the 
front page, so this 341 MB figure is meaningless.

I certainly understand laziness.  I don't approve of it, but I can 
understand it.  But I really don't understand _defending_ laziness.

His grasp of the English language was just fine.  He could have gotten 
the answer to his question by using Google with less time and effort 
than it took him to post to Usenet, wait for a response, and then act on 
it.  Even if he were totally lazy and selfish, he could have gotten the 
answer more easily by using Google for ten seconds.  Language was 
obviously not a barrier here, since the very words he used in asking the 
question could have been typed into a search engine to get exactly the 
answer he wanted.

There are plenty of questions that are complex enough, or require 
knowing the right terminology which might not be obvious to an 
interested amateur, such that a search engine won't be the most 
practical way to do research.  This was _certainly_ not one of those cases.

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Re: PEP 308 accepted - new conditional expressions

[John J. Lee]

"Michele Simionato" <[EMAIL PROTECTED]> writes:
[...]
> Guido could have decided two years ago, sparing us the PEP 308 ordalia.
> So, I am happy that at the end we will have a conditional operator, but
> I am not happy of how the process worked out. It was just an enormous
> waste of resources that could have been employed much better :-(

Seems that's what Guido thinks too:


http://mail.python.org/pipermail/python-dev/2005-September/056561.html

| If there's one thing I've learned from the PEP 308 vote, it is that
| votes for language don't work. I prefer some discussion on Python-dev
| after which I pick one.

I think he said at the time that it was an experiment.


John

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Nufox : Xul + Python

[salvatore . didio]

Hello,

You can test Nufox (with Firefox) at :

http://artyprog.no-ip.org

Regards

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Re: pywordnet install problems

[vdrab]

hello Steve,

I had WordNet 2.0 installed but just now I tried it with 1.7.1 as well
and the result was the same. It's a shame, glossing over the pywordnet
page really made me want to give it a try.
Are there any workarounds you can recommend ?
I had a quick look at the wordnet.py file, and it looks readable enough
to try and fiddle around with it, but if possible I'd like to avoid
having to mess with the source file.
Is there any other person / list I can ask for help on this?

thanks a lot.
vdrab.

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Re: Where to find python c-sources

[Michael]

John J. Lee wrote:
> "Tor Erik Sønvisen" <[EMAIL PROTECTED]> writes:
>> "Erik Max Francis" <[EMAIL PROTECTED]> wrote in message
>> > Tor Erik S�nvisen wrote:
>> >> I need to browse the socket-module source-code. I believe it's
>> >> contained in the file socketmodule.c, but I can't locate this file...
>> >> Where should I look?
>> > The source tarball, available on python.org.  Are people really too
>> > lazy to do elementary research on Google?
>> Thanks for the answers... And yes, I have searched google!
...
> Does google vary in its results across the globe?

Aside from Paul Boddie's comment to the effect of "yes", there is a very
important thing that people forget - *no everyone is as good at using a
search engine as others*. People are not simply as good at finding the same
information using the same tools as others.

You liken the problem to a library. If you understand how a library is laid
out, you can find the information alot quicker. If however you're looking
in a library for a book on "how to create those odd things for computers"
and you've been told it involves "python" you're as likely to end up in the
fiction section as you are zoology.

If you can't figure out the right search terms you need, google can be
useless. (That said when that happens to me, I tend to either use
kartoo.com or ask a friend)

The search terms might be obvious to you, but it simply means your google-fu
is strong, and the strong should help the weak. (or not attack them at
least...)


Michael.

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Re: Not defined

[Pekka Karjalainen]

In article <[EMAIL PROTECTED]>, Rob wrote:
>Forgive me please if this is not the proper place for this ?  I am trying to 
>keep an active brain :)

Seems proper to me :)

You can see what you've just imported by using the built-in
dir() function. Here's an example from my PyWin window:

>>> dir()
['__builtins__', '__doc__', '__name__', 'pywin']
>>> from math import *
>>> dir ()
['__builtins__', '__doc__', '__name__', 'acos', 'asin', 'atan', 'atan2',
'ceil', 'cos', 'cosh', 'degrees', 'e', 'exp', 'fabs', 'floor', 'fmod',
'frexp', 'hypot', 'ldexp', 'log', 'log10', 'modf', 'pi', 'pow', 'pywin',
'radians', 'sin', 'sinh', 'sqrt', 'tan', 'tanh']
>>> 

Note that the first time I use dir() it lists just four items. After from
math import * it lists all the stuff I got from the math module in
addition.

How does your dir() look after the import statement?

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Pekka Henrik Karjalainen

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Re: Not defined

[Kent Johnson]

Rob wrote:
> When trying the basic tutorial for cgkit I always seem to get a not defined 
> error as follows.
> 
> Pythonwin GUI
> 
> 
from cgkit import *
Sphere()
> 
> Traceback (most recent call last):
>   File "", line 1, in ?
> NameError: name 'Sphere' is not defined

Which version of cgkit are you using?

Kent
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Re: Not defined

[Pekka Karjalainen]

I looked around a bit and found the answer. At least the change I
recommend below worked for me.

In article <[EMAIL PROTECTED]>, Rob wrote:
>When trying the basic tutorial for cgkit I always seem to get a not defined 
>error as follows.
>
>Pythonwin GUI
>
 from cgkit import *

This is "from cgkit.all import *" in the tutorial here:

http://cgkit.sourceforge.net/doc2/node6.html

It seems the tutorial you are using is out of date vis-a-vis the version
of cgkit you use.

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list.join()... re.join()...? Do they exist? (newbie questions...)

[googleboy]

Hi.

In some google posts I searched suggested that there was a list.join()
thing that I assume works like string.join [which I notice is now
deprecated in favour of S.join()]

It seems that I have been misled.

I start with a text file that I split up to run some formatting over
the various sections with re.split.  I want to join it back together
again with a | delimeter and write it out to a new file.  I looked for
a re.join, but it seems that doesn't exist.   I looked for a list.join
after reading the aforementioned posts, but it doesn't seem to exist
either.

To get it to work I did this:


List[0] = list0
List[1] = list1
List[2] = list2
List[3] = list3
cat_list = list0 + '|' + flatblurb + '|' + flatcontents + '|' + flates
+ '\n'
file.write(concat_list)


But it seems to me that there is probably something more pythonic than
having to go about it in such a laborious fashion

Would someone be so kind as to fill me in?

TIA!

googleboy

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Re: list.join()... re.join()...? Do they exist? (newbie questions...)

[Benji York]

googleboy wrote:
> To get it to work I did this:
> 
> 
> List[0] = list0
> List[1] = list1
> List[2] = list2
> List[3] = list3
> cat_list = list0 + '|' + flatblurb + '|' + flatcontents + '|' + flates
> + '\n'
> file.write(concat_list)
> 
> But it seems to me that there is probably something more pythonic than
> having to go about it in such a laborious fashion

Indeed. :)

cat_list = '|'.join(List)
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Re: OT: Phases of the moon [was Re: A Moronicity of Guido van Rossum]

[Bart Lateur]

Steven D'Aprano wrote:

>A skeptical policeman who says he doesn't actually believe the moon
>affects behaviour nevertheless reports that "last weekend" things were
>really crazy, and it was a full moon. Somebody writes in to correct him:
>no, the full moon is actually "tomorrow".

As a similar example: I've been told by various women independently,
that "there are more babies born near a full moon."

So... is there a correlation between insanity and babies being born?  :)

-- 
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Re: Python 3! Finally!

[Duncan Booth]

Stefan Behnel wrote:

> Hi!
> 
> I just firefoxed to Python.org and clicked on the bz2 link at
> http://python.org/2.4.2/ and what did I get?
> 
> Python-3.4.2.tar.bz2 !!
> 
> Python 3 - what we've all been waiting for, finally, it's there!
> 
> Weird, though, the md5sum is the same as for the Python-2.4.2.tar.bz2
> that I downloaded late (late!) yesterday evening and had forgotten in
> my download directory... just found it next to the new one... was
> still there, not overwritten...
> 
> Well, maybe the changes needed to merit a V3 weren't that big after
> all... 
> 
Did you download the file using Firefox? It seems to have a 'feature' that 
when you download a file and there is already a file of the same name it 
finds the first number in the filename and increments it.

e.g. I just downloaded TortoiseSVN-1.2.4.4479-svn-1.2.3.msi and then 
immediately re-downloaded it and got TortoiseSVN-2.2.4.4479-svn-1.2.3.msi

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Re: A Moronicity of Guido van Rossum

[Xah Lee]

the programers in the industry, including bigwigs such as Guido or that
Larry Wall fuckhead, really don't know shit about computer languages.
Sometimes i get pissed by Stephen Wolfram's megalomaniac cries, but in
many ways, i think his statements about the fucking moronicities of the
academicians and otherwise dignitaries are justified.

here i will try to illuminate some miscellaneous things regarding the
lambda in Python issue.

as i have hinted
( http://xahlee.org/perl-python/list_comprehension.html ), the
so-called List Comprehension is just a irregular syntax to facilitate
generating lists. The name is a terrible jargon, and the means is also
quite fucked up. The proper name should be something like
ListGenerator, and the proper means should be the plain function.

For instance, Python's range() is such a list generator, only that it
is limited in scope.

For a example of a powerful list generator, see Mathematica's Table
function:
http://documents.wolfram.com/mathematica/functions/Table

i'm running a project that will code Table in Perl and Python and Java.
You can read about the spec and source code here:
http://xahlee.org/tree/Table.html
(note: the Python version there isn't complete)

Note Table's power in generating not just flat lists, but trees. And if
one really want flat lists, there's the Flatten function that flats any
nested lists. (Python should have this too)

Python's reduce() is Mathematica's Fold. See
http://documents.wolfram.com/mathematica/functions/Fold
Besides Fold, there's FoldList, FixedPoint, FixedPointList, Nest,
NestList and others. In Python's terms, FoldList is like reduce()
except it returns a list of each steps. FixedPoint recursively applies
a function to itself until the result no longer changes (or when a
optional function returns true) Nest is similar except it limits the
iteration by a number. The NestList and FixedPointList are similar
except that they return a list, containing all the steps.

All these can be written as a loop, but they make the code condensed
and meaning clear. More so, they are important when programing in a
functional style. In functional programing, you don't litter lots of
variables or temporary functions or intermediate loops here or there on
every other line. The code is usually tight and inline. When sequencing
a series of functions, you can't stop in the middle and do some loop or
auxiliary calculation. All these are made inline into a function. (that
is: constructed as lambda) A block of code usually corresponds to a
unit of the algorithm used, as opposed to the particular unit of the
implementation of the algorithm. You don't read the minute details of
the code. You read the algorithmic unit's comments, or just the input
and output of a code block.

Also, these inline loop constructs are not just for computing numbers
as Guido likes to ignorantly think. They are specialized forms of
generic loop constructs. Their first argument is a function, and second
argument is a list. Their generality lies with the fact that their
first argument is a function. If a language does not provide a
convenient way to represent the concept of a function, than these
functional loop constructs will suffer in usability.

The Python morons, did not provide a convenient way to represent a
function. (they tried, with their limited implementation of lambda and
shun it like a plaque)

The way Guido puts it gives us a nice glimpse of their retarded
mentality: “Also, once map(), filter() and reduce() are gone, there
aren't a whole lot of places where you really need to write very short
local functions;”

As we can see here, in Pythoner's mind, lambda is for “very short
local functions”.

Python's limited lambda coupled with their lambda attitude problem
among imperative morons, therefore functional programing suffers in
Python, and consequently one becomes so stupid as to come up with a
bunch of feelings about lambda, map, reduce, filter.

For Python's map(), look at Mathematica's Map on how it might be
extended.
http://documents.wolfram.com/mathematica/functions/Map
Note the ability to map to not just flat lists but trees (nested
lists). Note the power of expressing the concept of levels of a tree.

For Python's filter(), check out the equivalent in Mathematica's
Select:
http://documents.wolfram.com/mathematica/functions/Select
Note how it provides a third option for picking just the first n items.
Also note, that Select is just a way to pick elements in a list.
Mathematica provides a set to do these: Part, Take, Drop, Select,
Cases. All uniformly uses the function syntax and all operate
semantically by returning a new list. In Python and other imperative
clown's language, usually they provide a limited varieties to do such a
task, and also inconsistent like piled on. (e.g. alist[5:9], filter(),
alist.remove(...), del alist[...]). Some modify the list in-place, some
returns a new list.

-

one is quite sorry to read a big shot contemplating on petty

Re: Help with syntax warnings

[Ivan Shevanski]

Well I've been experimenting with the warning filter and it doesn't seem to 
be working. . .I think it has something to do with the fact that warnings 
are issued during the compiling and not during the excecution. . .So the 
filter would come in to late to block them? Any ideas?

-Ivan

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Re: Help with syntax warnings

[Fredrik Lundh]

Ivan Shevanski wrote:

> Well I've been experimenting with the warning filter and it doesn't seem to
> be working. . .I think it has something to do with the fact that warnings
> are issued during the compiling and not during the excecution. . .So the
> filter would come in to late to block them? Any ideas?

fix your code.

fixing syntaxwarnings is almost always trivial; most of the time, all you
have to do is to remove (or rephrase) some statement that doesn't do
what you think it does anyways...

if you really cannot motivate yourself to fix your code, you have to add
an extra "bootstrap" module.  if your program is named "myprogram.py",
rename that file to "myactualprogram.py", and add a "myprogram.py" that
looks like this:

# File: myprogram.py

import warnings
warnings.simplefilter("ignore", SyntaxWarning)
import myprogram

(you may have to fix any __name__ == "__main__" clauses in your original
program).

but you really should fix your program, instead of wasting time on stupid
workarounds.





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Re: [Info] PEP 308 accepted - new conditional expressions

[Sam]

Leif K-Brooks writes:


Sam wrote:

And "foo if bar" is Perl-ish; yet, even Perl has the ? : operators.


What _isn't_ Perl-ish?


BASIC?




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Re: A Moronicity of Guido van Rossum

[gene tani]

(posted c.l.python ONLY)

Xah (may i call you Xah?)

SOrry to say, but your older posts were much funnier:

http://groups.google.com/group/comp.lang.lisp/browse_frm/thread/15f7015d23a6758e/9ee26da60295d7c8?lnk=st&q=&rnum=5&hl=en#9ee26da60295d7c8

(also seems your anti-cult cult really hasn't gotten a lot of
followers.  You might want to change password on your email account and
this time not give it out to all your friends.

Anyway, good luck in all your future endeavors.  Um, don't have to keep
in touch, tho.

Xah Lee wrote:
> the programers in the industry, including bigwigs such as Guido or that
> Larry Wall fuckhead, really don't know shit about computer languages.

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Re: [Info] PEP 308 accepted - new conditional expressions

[Ron Adam]

Reinhold Birkenfeld wrote:

> Ron Adam

>>I think I'm going to make it a habit to put parentheses around these 
>>things just as if they were required.


> Yes, that's the best way to make it readable and understandable.
> 
> Reinhold

Now that the syntax is settled, I wonder if further discussion on the 
contextual behavior could be done?  Or maybe it was already done off 
line or in private email?

To me the advantage of a if b else c form is the easy chaining to build 
up a sum of conditional parts, where each next part is dependent on the 
previous result.

The advantage of the nested form, is it can be used in place of an 
if-elif-else structure.  But I think the (a if b else c) syntax doesn't 
match that behavior very well so I was expecting the default behavior to 
be the sequential chaining and not nested evaluation.

But of course, by explicitly placing parentheses, you can do either. 


Cheers,
Ron








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Re: Will python never intend to support private, protected and public?

[Mike Meyer]

Paul Rubin  writes:

> Mike Meyer <[EMAIL PROTECTED]> writes:
>> Unless your compiler detects and flags passing private variables to
>> external functions all you've got is a convention that you don't pass
>> private variables to external functions.
> Yes, the point is that it's something that you can check for by
> examining the class in question without having to examine any other
> classes.

That's a pretty restrictive convention to follow. For instance, I
might want an error dialog to be a private variable of a class
representing a window - after all, I don't want anyone else writing to
it, or using it in any way. Except, of course, for any GUI framework
routines I have to pass it to in order to use it. This problem crops
up for every utility routine in every library I might want to
use. Opening files by name, concatenatting strings (or are we going to
have a convention that implicit invocation of functions with the
operator syntax don't count, and another one that you don't overload
operators with destructive functions, and so on), etc.

So it turns out that getting the behavior you desire involves
following a lot of conventions.

>> I you going to try and tell me thas using builtin functions on
>> private variables is something you don't allow in your projects?
>
> You have to treat builtin functions as part of the language.  Of
> course Python has this situation where someone could rebind the name
> "len" to some other function, so you have to deal with that too, maybe
> just at the file scope.

File scope isn't good enough for python.

import madhouse
madhouse.len = my_len_breaker
fool = madhouse.Fool()
print fool.break()

and fool._foo is broken again.

> An OOP approach (lst.len() instead of len(lst)) that binds the
> builtin names to datatypes might be preferable in some situations
> but I'll leave that one for the theorists.

In other words, to get this to work the way you want, you need yet
another convention - this one being about how one goes about writing
utility functions. It may be that you can design a language and
support libraries so that the compiler can enforce all your
conventions. There are languages that try to do that. I recall one I
ran into in the 70s that distinguished between "functions" (which
returned values) and "procedures" (which had side effects), and the
compiler enforced (or tried to) the distinction. I think you'd need
something like that.

But that isn't what we've got. What we've got is Python. Which means
you need a whole boatload of conventions to make this work the way you
want.

In other words, by adding private to python, you're making it so that
bugs involving overwriting a private attribute will involve only the
owning classes code so long as everyone follows the conventions that
exist about the use of such variables.

This should be contrasted with the current situation, where bugs that
involve overwriting an _-prefixed attribute will involve only the
owning classes code so long as everyone follows the conventions that
exist about the use of such variables.

Yeah, I guess private makes things a lot better.

>> Of course, there's nothing wrong with catching errors earlier. Might I
>> suggest that you file a change request for pylint (or your favorite
>> error checker) asking that it start issuing warnings for
>> object._variable?
>
> I don't see how pylint could know which instances to flag, without
> doing type inference on all the objects to know that the variable
> belonged to an instance of some other class.

I was thinking it would flag any use of such a variable where the
target variable wasn't "self". That may be a stronger constraint than
you wanted - but that's good, right?

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Re: Nufox : Xul + Python

[salvatore . didio]

Oops:

http://artyprog.noip.org:8080

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Re: OT: Phases of the moon

[Mike Meyer]

Bart Lateur <[EMAIL PROTECTED]> writes:

> Steven D'Aprano wrote:
>
>>A skeptical policeman who says he doesn't actually believe the moon
>>affects behaviour nevertheless reports that "last weekend" things were
>>really crazy, and it was a full moon. Somebody writes in to correct him:
>>no, the full moon is actually "tomorrow".
>
> As a similar example: I've been told by various women independently,
> that "there are more babies born near a full moon."
>
> So... is there a correlation between insanity and babies being born?  :)

If what they say is true, then yes, there is. That doesn't mean
there's a logical - or even rational - explanation for that
correlation.

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Re: OT: Phases of the moon [was Re: A Moronicity of Guido van Rossum]

[Paul F. Dietz]

Bart Lateur wrote:

> As a similar example: I've been told by various women independently,
> that "there are more babies born near a full moon."

That's also a myth.

Paul
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Re: Nufox : Xul + Python

[Lars Heuer]

Hi,

> Oops:

> http://artyprog.noip.org:8080


Again Oops:  :))

http://artyprog.no-ip.org:8080

Best regards,
Lars
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Re: Help with syntax warnings

[Peter Otten]

Ivan Shevanski wrote:

> Well I've been experimenting with the warning filter and it doesn't seem
> to be working. . .I think it has something to do with the fact that
> warnings are issued during the compiling and not during the excecution. .
> .So the filter would come in to late to block them? Any ideas?

$ cat syntaxwarning.py
def f():
x = 42
global x
$ python2.4 syntaxwarning.py
syntaxwarning.py:1: SyntaxWarning: name 'x' is assigned to before global
declaration
  def f():

Method 1: precompile the py-file and then invoke the compiled variant:

$ python2.4 -c 'import syntaxwarning'
syntaxwarning.py:1: SyntaxWarning: name 'x' is assigned to before global
declaration
  def f():
$ python2.4 syntaxwarning.pyc

Method 2: switch off the warning:

$ python2.4 -Wignore::SyntaxWarning syntaxwarning.py

Peter

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Re: OT: Phases of the moon [was Re: A Moronicity of Guido van Rossum]

[Ulrich Hobelmann]

Paul F. Dietz wrote:
> Bart Lateur wrote:
> 
>> As a similar example: I've been told by various women independently,
>> that "there are more babies born near a full moon."
> 
> That's also a myth.

Right, everybody knows that it's not natural (moon) light that 
influences reproductive behavior, it's artificial light -- TV.

When TV is turned off by a power failure, lots of people that usually 
never have sex start making love, and lots of people that usually use 
contraception lose their minds and forget about it.

9 months later more babies are born, unless that's also a myth.

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Re: Will python never intend to support private,protected and public?

[en.karpachov]

On 30 Sep 2005 15:00:39 -0700
Paul Rubin wrote:

> Rocco Moretti <[EMAIL PROTECTED]> writes:
> > There is little in the way of technical problems that are solved by
> > language level enforcement of private variables. The issues in
> > question are mostly social ones, and if you're not reading and
> > following the documented interface, stopping private variable access
> > is not going to prevent most of your problems.
> 
> Well, that says you consider both code auditing and debugging to be
> social problems rather than technical ones.  Maybe that's reasonable,

By the way, any programming language is a social issue; only machine code
is technical.

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Re: [Info] PEP 308 accepted - new conditional expressions

[en.karpachov]

On Fri, 30 Sep 2005 21:28:26 -0400
Terry Reedy wrote:
> 
> The lesson for me is to spend much less time on Python discussion and much 
> more on unfinished projects.  So even if I never use the new syntax, I will 
> have gained something ;-)

QOTW?

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Re: Will python never intend to support private, protected and public?

[en.karpachov]

On 30 Sep 2005 22:11:46 +
John J. Lee wrote:

> Steve Holden <[EMAIL PROTECTED]> writes:
> > That would make a good Onion (www.TheOnion.com) headline: "Users 
> > Discover Computer Security Conflicts with Desire for Convenience"
> 
> :-) The Onion, yay.
> 
> Area Man Forgets Work Password, Will Employ Post-It Notes in Future

Sure. It would be fun to read something about "Consenting Adults" there,
too.

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Printing and prompting adds a mysterious extra space

[Christoph Haas]

Evening...

I'm writing a simple interactive program to maintain a database.
The goal was to print "> " at the beginning of the line, wait for
user input and then deal with it. Minimal test program:

import sys; print ">", ; print sys.stdin.readline()

However when I run the program and enter "foobar" it looks like this:

./test.py
>foobar
 foobar
^--- where does this space come from?

I wonder where the space comes from in the line where I print what the
user typed. Does it have to do with the "," after the print which I use
to suppress the newline? Any ideas?

Regards
 Christoph
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Re: Nufox : Xul + Python

[bearophileHUGS]

Nufox seems a really interesting thing (probably it can even be used to
design GUIs for local desktop apps), but the site seems down at the
moment.

Bye,
bearophile

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Re: OT: Phases of the moon

[Sherm Pendley]

Bart Lateur <[EMAIL PROTECTED]> writes:

> As a similar example: I've been told by various women independently,
> that "there are more babies born near a full moon."
>
> So... is there a correlation between insanity and babies being born?  :)

If you weren't insane before the baby was born, you will be soon after. ;-)

sherm--

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Re: Not defined

[Rob]

Thanks for the replies gives me something to chew on.

Regards Gramps 


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Re: Printing and prompting adds a mysterious extra space

[[EMAIL PROTECTED]]

Christoph Haas wrote:
> Evening...
>
> I'm writing a simple interactive program to maintain a database.
> The goal was to print "> " at the beginning of the line, wait for
> user input and then deal with it. Minimal test program:
>
> import sys; print ">", ; print sys.stdin.readline()
>
> However when I run the program and enter "foobar" it looks like this:
>
> ./test.py
> >foobar
>  foobar
> ^--- where does this space come from?
>
> I wonder where the space comes from in the line where I print what the
> user typed. Does it have to do with the "," after the print which I use
> to suppress the newline? Any ideas?

Another question you could ask is: why is there NO space after
the '>'? Have a look at this.

import sys

print ">",

s = sys.stdin.readline()

print len(s)
print s
for i in s:
print ord(i),i

Instead of printing the input, I'm assigning it to a variable.
Notice that the extra space appears on the next print statement
and is not part of the input. this is verified by showing that
the input has exactly 4 characters and is "huh\n".

>>>
>huh
 4
huh

104 h
117 u
104 h
10


So it looks like the space was sitting in the output buffer.

>
> Regards
>  Christoph
> --
> I'm still confused - just on a higher level now.
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Re: OT: Phases of the moon [was Re: A Moronicity of Guido van Rossum]

[Running Bare]

Ulrich Hobelmann <[EMAIL PROTECTED]> writes:

> When TV is turned off by a power failure, lots of people that
> usually never have sex start making love, and lots of people that
> usually use contraception lose their minds and forget about it.
>
> 9 months later more babies are born, unless that's also a myth.

http://www.snopes.com/pregnant/blackout.htm

"Despite initial reports of New York City hospitals' seeing a
dramatic increase in the number of births nine months after the
1965 blackout, later analyses showed the birth rate during that
period to be well within the norm."


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Re: Zope3 Examples?

[Jaime Wyant]

If you're experimenting with frameworks, try out django.  I've only
completed a few parts of the tutorial.  However, what amazes me is how
much I got for so little code.  It's slick.

http://www.djangoproject.com/

jw

On 9/30/05, Markus Wankus <[EMAIL PROTECTED]> wrote:
> Gerhard Häring wrote:
> > Markus Wankus wrote:
> >> [...] Thanks for the reply - maybe I'll give it another shot.  I'm
> >> currently demoing Snakelets.  Quite a turn in the opposite direction,
> >> but small and super-easy to get going with. [...]
> >
> > I also found Snakelets a pleasure to use and chose it for implementing a
> > clan homepage in early 2005.
> >
> > I'm still very interested in the Python/Web/RDBMS field and tried to
> > follow the developments since then. I didn't actually build anything
> > real, only played a little bit with CherryPy and the megaframeworks
> > built upon, Subway and TurboGears.
> >
> > If I had to choose again, I'd use TurboGears, despite the fact that it's
> > very young and still developing.
> >
> > -- Gerhard
> >
>
> Good to know.  I have watched the screencast for Turbogears but haven't
> tried it yet.  There seemed to be a lot of "magic" methods going on
> there, and you could tell the guy doing the screencast had done that
> more than once. ;o)  I guess once you run through the manual it would
> all make sense.
>
> I figure I'll give Snakelets a good go first.  Is your Snakelets-based
> page up and accessible somewhere?
>
> Markus.
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Re: Printing and prompting adds a mysterious extra space

[Christoph Haas]

On Sat, Oct 01, 2005 at 01:17:41PM -0700, [EMAIL PROTECTED] wrote:
> Christoph Haas wrote:
> > I'm writing a simple interactive program to maintain a database.
> > The goal was to print "> " at the beginning of the line, wait for
> > user input and then deal with it. Minimal test program:
> >
> > import sys; print ">", ; print sys.stdin.readline()
> >
> > However when I run the program and enter "foobar" it looks like this:
> >
> > ./test.py
> > >foobar
> >  foobar
> > ^--- where does this space come from?
> 
> Another question you could ask is: why is there NO space after
> the '>'? Have a look at this.
> [...]
> So it looks like the space was sitting in the output buffer.

Yes, probably. But how do I get that buffer flushed? I tried
sys.stdout.flush() after the print statement but it wasn't printed,
either. I probabl need something like...

print "> "+

instead of

print ">",

How could I solve that decently?

 Christoph
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Re: Nufox : Xul + Python

[Michael]

Lars Heuer wrote:
>> Oops:
>
>> http://artyprog.noip.org:8080
> 
> 
> Again Oops:  :))
> 
> http://artyprog.no-ip.org:8080

Looks intriguing, but the examples on the site won't work for me. I
suspect they won't for anyone else either, because the code in the
webpages appears to try and contact a server in a private address
space, specifically 192.168.0.40.

Which is a pity, because it looks interesting :-)

Regards,


Michael.
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Re: Printing and prompting adds a mysterious extra space

[jepler]

Use sys.stdout.write instead of print.  It will solve these problems you are
having.

If you really want to know what's going on, read the language manual,
http://docs.python.org/ref/print.html It explains the behavior of this extra
space, which is output by a successive 'print' statement.  The implementation
uses an attribute called 'softspace', which is described in
http://docs.python.org/lib/bltin-file-objects.html 

Jeff


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Class Help

[Ivan Shevanski]

To continue with my previous problems, now I'm trying out classes.  But I 
have a problem (which I bet is easily solveable) that I really don't get.  
The numerous tutorials I've looked at just confsed me.For intance:

>>>class Xyz:
... def y(self):
... q = 2
...
>>>Xyz.y()
Traceback (most recent call last):
  File "", line 1, in ?
TypeError: unbound method y() must be called with Xyz instance as first 
argument
(got nothing instead)


So. . .What do I have to do? I know this is an extremley noob question but I 
think maybe if a person explained it to me I would finally get it =/


thanks in advance,

-Ivan

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Re: Class Help

[Ron Adam]

Ivan Shevanski wrote:
> To continue with my previous problems, now I'm trying out classes.  But 
> I have a problem (which I bet is easily solveable) that I really don't 
> get.  The numerous tutorials I've looked at just confsed me.For intance:
> 
 class Xyz:
> 
> ... def y(self):
> ... q = 2
> ...
> 
 Xyz.y()
> 
> Traceback (most recent call last):
>  File "", line 1, in ?
> TypeError: unbound method y() must be called with Xyz instance as first 
> argument
> (got nothing instead)
> 
> 
> So. . .What do I have to do? I know this is an extremley noob question 
> but I think maybe if a person explained it to me I would finally get it =/
> 
> 
> thanks in advance,
> 
> -Ivan

Generally you don't use class's directly.  Think if them as templates 
for objects.  Then you can use that class (template) to create many objects.

To create an object just call the class and assign the result to a name.

xyz = Xyz()
xyz.y()


Also,

In your example 'q' is assigned the value 2, but as soon as the method 
'y' exits, it is lost.  To keep it around you want to assign it to self.y.

class Xyz(object):   #  create an class to create an object instance.
def y(self)
   self.q = 2

xyz = Xyz()
xyz.y()
print xyz.q  #  prints 2



Cheers,
Ron











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Re: Class Help

[marduk]

On Sat, 2005-10-01 at 18:58 -0400, Ivan Shevanski wrote:
> To continue with my previous problems, now I'm trying out classes.  But I 
> have a problem (which I bet is easily solveable) that I really don't get.  
> The numerous tutorials I've looked at just confsed me.For intance:
> 
> >>>class Xyz:
> ... def y(self):
> ... q = 2
> ...
> >>>Xyz.y()
> Traceback (most recent call last):
>   File "", line 1, in ?
> TypeError: unbound method y() must be called with Xyz instance as first 
> argument
> (got nothing instead)
> 
> 
> So. . .What do I have to do? I know this is an extremley noob question but I 
> think maybe if a person explained it to me I would finally get it =/


When you define a class, say Xyz, your are defining your own type.  Say
that Person is a class.  And person has a method walk():

class Person:
def walk(self):
...

now to use the Person class, you need to create an instance of it.  You
can't just say Person.walk() because Person is a "class"ification, not a
real object.  You need an instance of person.

jane = Person()

This creates a new person called "jane".  "jane" is an instance of the
class Person.

>>> jane
 <__main__.Person instance at 0x2c723710>

Now we can tell jane to walk:

jane.walk()

So what the error is telling you (in a bit confusing way if you're a
newbie) is that you are calling a method y() but you have not created an
instance of your Xyz class to do y().  Or, to use my analogy, you are
telling Person to walk, but you can't make Person walk, you have to
create a person, jane, and have jane walk.

Hope this helps, but I recommend you read a good intro to
object-oriented programming.

-a

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Re: Class Help

[Jean-François Doyon]

You have to crate an instanciation of the class before you can use one.

So you want to do:

instance = Xyz()
instance.y()

You won't get any output though, might want to do:

class Xyz:
 def y(self):
 print 'y worked!'

it's more satisfying :)

Basically, look into the difference between a class, and the INSTANCE of 
a class.

Cheers,
J.F.

Ivan Shevanski wrote:
> To continue with my previous problems, now I'm trying out classes.  But 
> I have a problem (which I bet is easily solveable) that I really don't 
> get.  The numerous tutorials I've looked at just confsed me.For intance:
> 
 class Xyz:
> 
> ... def y(self):
> ... q = 2
> ...
> 
 Xyz.y()
> 
> Traceback (most recent call last):
>  File "", line 1, in ?
> TypeError: unbound method y() must be called with Xyz instance as first 
> argument
> (got nothing instead)
> 
> 
> So. . .What do I have to do? I know this is an extremley noob question 
> but I think maybe if a person explained it to me I would finally get it =/
> 
> 
> thanks in advance,
> 
> -Ivan
> 
> _
> Express yourself instantly with MSN Messenger! Download today - it's 
> FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
> 
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Background process for ssh port forwarding

[Jesse Rosenthal]

Hello all,

I'm writing a script which will backup data from my machine to a server
using rsync. It checks to see if I am on the local network. If I am, it
runs rsync over ssh to 192.168.2.6 using the pexpect module to log in.
That's the easy part.

Now, when I'm not on the local network, I first want to open up an ssh
connection to do port forwarding, so something like this:

def hostforward():
#This is based on the assumption that the passfile is the gnus
#authinfo file, or has a similar format...
f = open(PASS_FILE, "r")
f_list = f.read().split(' ')
f.close()
#Now, we get the entry after "password" (be slicker to make it a
#dictionary, but maybe wouldn't work as well).
pass_index = f_list.index('password') + 1
forwardpass = f_list[pass_index]
#now we connect
command = 'ssh -l %s -L 2022:%s:22 %s' % \
  (login, my_server, forwarding_server)
connection = pexpect.spawn(command)
connection.expect('.*assword:')
connection.sendline(forwardpass)

If I end this with 'connection.interact()', I will end up logged in to the
forwarding server. But what I really want is to go on and run rsync to
localhost port 2022, which will forward to my_server port 22. So, how can
I put the ssh connection I set up in hostforward() in the background?
I need to make sure that connection is made before I can run the rsync
command.

I've looked at threading, but that seems excessive. There must be an
easier way. Whatever I do, though, I'll need to use pexpect to spawn the
processes, since I'll need to log in to ssh servers with a password.

Thanks for any help.

--Jesse


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Re: Class Help

[Ron Adam]

Ron Adam wrote:

> Also,
> 
> In your example 'q' is assigned the value 2, but as soon as the method 
> 'y' exits, it is lost.  To keep it around you want to assign it to self.y.

Ooops,  That should say ...
"To keep it around you want to assign it to self.q."   <---self.q

Cheers,
Ron
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Re: Printing and prompting adds a mysterious extra space

[Christoph Haas]

On Sat, Oct 01, 2005 at 05:09:48PM -0500, [EMAIL PROTECTED] wrote:
> Use sys.stdout.write instead of print.  It will solve these problems you are
> having.
> 
> If you really want to know what's going on, read the language manual,
> http://docs.python.org/ref/print.html It explains the behavior of this extra
> space, which is output by a successive 'print' statement.  The implementation
> uses an attribute called 'softspace', which is described in
> http://docs.python.org/lib/bltin-file-objects.html 

Thank you for the technical explanation. "print a,b" is nice to read
in simple Python programs. But when you need to get more control of
I/O it's better to know what's really happening inside.

So the "softspace" is always added after a "print a," statement but only
printed if Python thinks it is not at the beginning of a terminal line.
Interesting.

Again, thanks. I'll rest my case.

 Christoph
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~
~
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Re: A rather unpythonic way of doing things

[Tom Anderson]

On Thu, 29 Sep 2005, Peter Corbett wrote:

> One of my friends has recently taken up Python, and was griping a bit 
> about the language (it's too "prescriptive" for his tastes). In 
> particular, he didn't like the way that Python expressions were a bit 
> crippled. So I delved a bit into the language, and found some sources of 
> syntactic sugar that I could use, and this is the result:
>
> http://www.pick.ucam.org/~ptc24/yvfc.html

It's this sort of thing that makes it clear beyond all shadow of a doubt 
that Cambridge should be razed to the ground.

Keep up the good work.

tom

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Re: User-defined augmented assignment

[Tom Anderson]

On Thu, 29 Sep 2005, Pierre Barbier de Reuille wrote:

> a discussion began on python-dev about this. It began by a bug report, 
> but is shifted and it now belongs to this discussion group.
>
> The problem I find with augmented assignment is it's too complex, it's
> badly explained, it's error-prone. And most of all, I don't see any
> use-case for it !
>
> The most common error is to consider that :
>
> a += b <==> a.__iadd__(b)
>
> when the truth is :
>
> a += b <==> a = a.__iadd__(b)
>
> which can be very confusing, as the two "a" are not necessarily the
> same.

Indeed. I certainly didn't realise that was how it worked.

> So, what I would suggest is to drop the user-defined augmented 
> assignment and to ensure this equivalence :
>
> a X= b <=> a = a X b
>
> with 'X' begin one of the operators.

That seems quite an odd move. Your proposal would lead to even more 
surprising behaviour; consider this:

a = [1, 2, 3]
b = a
a += [4, 5, 6]
print b

At present, this prints [1, 2, 3, 4, 5, 6]; if we were to follow your 
suggestion, it would be [1, 2, 3].

So, -1, i'm afraid.

I think the right solution here is staring us in the face: if everyone 
seems to think that:

a += b <==> a.__iadd__(b)

Then why not make it so that:

a += b <==> a.__iadd__(b)

Principle of Least Surprise and all that.

Since not everything that should support += is mutable (integers, for 
example), how about saying that if the recipient of a += doesn't have an 
__iadd__ method, execution falls back to:

a = a + b

I say 'a + b', because that means we invoke __add__ and __radd__ 
appropriately; indeed, the __add__ vs __radd__ thing is a precedent for 
this sort of fallback.

Doesn't that leave everyone happy?

tom

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Re: Python 3! Finally!

[Tom Anderson]

On Fri, 30 Sep 2005, Stefan Behnel wrote:

> I just firefoxed to Python.org and clicked on the bz2 link at
> http://python.org/2.4.2/ and what did I get?
>
> Python-3.4.2.tar.bz2 !!
>
> Python 3 - what we've all been waiting for, finally, it's there!

Not only that, but they've skipped the tiresome 3.0.x early release 
teething phase and gone straight to the mature, solid-as-a-rock middle 
releases! God, i love python!

Hey, and it's still got lambdas! WE WON!!!

tom

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Re: Class Help

[Steven D'Aprano]

On Sat, 01 Oct 2005 18:58:45 -0400, Ivan Shevanski wrote:

> To continue with my previous problems, now I'm trying out classes.  But I 
> have a problem (which I bet is easily solveable) that I really don't get.  
> The numerous tutorials I've looked at just confsed me.For intance:

[code snipped]


You have to keep in mind the difference between a class and an instance of
a class. To make an analogy with real life, a class is like the idea of
"dogs in general" and an instance is a specific dog (like Ol' Yella, or
Rin Tin Tin, or or that little beagle on the Enterprise).

Normally you create a class, then make one or more instance of the class,
and work with the instances.

Some terminology for you to learn: when you create a function inside a
class, it is called a class method, or just method. Functions and methods
are not exactly the same, but for now the differences don't concern us.

So, you create a class with a single method:

class Klass:
def spam(self):
return "spam " * 5

Notice that the first argument of the method is always "self", even when
you don't need any arguments.

Klass is an object, and you can call Klass.spam() if you like, but it will
fail because you haven't included an argument for self. self must be an
instance of Klass. So you could do this:

spam_maker = Klass()  # create an instance
print Klass.spam(spam_maker)

which will print "spam spam spam " as expected.

But that's doing extra work. Once you have your instance, you can just
call the method as if it were a normal function:

print spam_maker.spam()

and it will work the way you expect it to. Behind the scenes, Python
passes a copy of spam_maker to spam_maker.spam() for you. It can do that
because spam_maker is an instance.

A class is a description of how a type of object should work, but you
normally don't work directly on that high-level description. Normally you
will work with individual instances, not the class itself. When Timmy
falls down the well, you tell Rin Tin Tin to go get help, not "dogs in
the general".

Python built in objects like lists, strings, ints etc are special types of
classes built into the language. Here is how we might create a (very
inefficient!) Python implementation of list:

class MyList:

# Class attributes:

left_delimiter = "["
right_delimiter = "]"
item_delimiter = ", "

# Class methods:

def __init__(self, *arguments):
"""Create a new instance and fill it with arguments."""
self.data = arguments  # create an instance attribute
def __str__(self):
"""Convert instance to a string for printing."""
holder = self.left_delimiter
for item in self.data:
holder = holder + str(item) + self.item_delimiter
holder = holder + self.right_delimiter
return holder
def append(self, obj):
"""Append an object to the instance."""
self.data.append(obj)
# real lists have many more methods...



Hope this helps.


-- 
Steven.


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Re: Soap Question (WSDL)

[Armin]

Thanks for the comment everyone.

I was considering to write my own soap interface to Flickr as apposed
to use the ready to go libraries for Flickr as Fredrik pointed out. I
got to get FlickrClient to work. Nonetheless, I am excited to use soap
services for my needs.

Thanks for your support,
Armin

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How is wxWindows related to Python?

[Sathyaish]

My question will sound daft to the good old craftsmen, but they will
excuse my nescience on the subject. I come new to the Pythonic world
from the land of .NET languages, VB6 and some familiarity in C and C++.

I just read about wxWindows last night. From my understanding, it is a
GUI framework like MFC that lets you create UI apps with ease calling a
standard set of API accross multiple platforms (unlike MFC) and if the
Windows port is complementary to MFC in that it shields you from
calling the Win32 API directly.

However, I do not understand its correlation with Python. The
documentation page says, "wxWindows 2.4.2: A portable C++ and Python
GUI toolkit." So, my question is, "How is wxWindows related to Python?"

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Re: PyWin SendMessage

[Tim Roberts]

Gonzalo Monzón <[EMAIL PROTECTED]> wrote:
>
>Hi Gerd,
>
>I'm not really sure of, but I think you must use a message value in 
>range of WM_USER or WM_APP so this fact maybe let the receiver window 
>getting bad data... 

No.  WM_COPYDATA is designed specifically for his use case -- interprocess
communication.  The WM_USER range is only if you are inventing a custom
message for some new purpose.
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Re: How is wxWindows related to Python?

[Jaime Wyant]

That is a reference to wxPython.  wxPython is a thin wrapper around
the wxWidgets c++ library.  But really, it has grown quite a bit
lately and has a bunch of neato widgets that aren't included with
wxWidgets c++.

Visit www.wxpython.org.

jw

On 1 Oct 2005 18:36:06 -0700, Sathyaish <[EMAIL PROTECTED]> wrote:
> My question will sound daft to the good old craftsmen, but they will
> excuse my nescience on the subject. I come new to the Pythonic world
> from the land of .NET languages, VB6 and some familiarity in C and C++.
>
> I just read about wxWindows last night. From my understanding, it is a
> GUI framework like MFC that lets you create UI apps with ease calling a
> standard set of API accross multiple platforms (unlike MFC) and if the
> Windows port is complementary to MFC in that it shields you from
> calling the Win32 API directly.
>
> However, I do not understand its correlation with Python. The
> documentation page says, "wxWindows 2.4.2: A portable C++ and Python
> GUI toolkit." So, my question is, "How is wxWindows related to Python?"
>
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>
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Re: How is wxWindows related to Python?

[Benji York]

Sathyaish wrote:
> However, I do not understand its correlation with Python. The
> documentation page says, "wxWindows 2.4.2: A portable C++ and Python
> GUI toolkit." So, my question is, "How is wxWindows related to Python?"

"Pure" wxWindows (actually it's been renamed wxWidgets at the demand of 
Microsoft) is for C++.  You're looking for wxPython: http://wxpython.org/
--
Benji York



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Re: How is wxWindows related to Python?

[Brett Hoerner]

I guess it is referring to the closely related (maybe even same dev
group? I don't know why the wxWindows docs would mention Python unless
they specifically support the wxPython project, too.)

"wxWindows + Python = wxPython

wxPython is a Python extension module that provides a set of bindings
from the wxWindows library to the Python language. In other words, the
extension module allows Python programers to create instances of
wxWindows classes and to invoke methods of those classes.

More from this Chapter:

· Using Tkinter

· Using PythonWin

The wxPython extension module attempts to mirror the class hierarchy of
wxWindows as closely as possible. This means that there is a wxFrame
class in wxPython that looks, smells, tastes, and acts almost the same
as the wxFrame class in the C++ version.

wxPython is close enough to the C++ version that the majority of the
wxPython documentation is actually annotations to the C++ documentation
that describe the places where wxPython is different. There is also a
series of sample programs included, and a series of documentation pages
that assist the programmer in getting started with wxPython. "
http://www.onlamp.com/pub/a/python/excerpts/chpt20/wxpython.html

http://www.wxpython.org/

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Re: Class Help

[Peter]

Ivan Shevanski wrote:

>To continue with my previous problems, now I'm trying out classes.  But I 
>have a problem (which I bet is easily solveable) that I really don't get.  
>The numerous tutorials I've looked at just confsed me.For intance:
>
>  
>
class Xyz:


>... def y(self):
>... q = 2
>...
>  
>
Xyz.y()


>Traceback (most recent call last):
>  File "", line 1, in ?
>TypeError: unbound method y() must be called with Xyz instance as first 
>argument
>(got nothing instead)
>
>
>So. . .What do I have to do? I know this is an extremley noob question but I 
>think maybe if a person explained it to me I would finally get it =/
>
>  
>
You have to create an instance of the class before it can be called. Ex:
class foo:
def bar(self):
print "Hello, World!"
foo().bar()

This is because foo is a reference to a classobj, however, when you call 
the class, it becomes an instance.

Ex:
 >>> type(foo)

 >>> type(foo())


When an instance is created it tells Python to pass the instance as the 
first argument (self).
Otherwise it gives it None or something similer. (Note that im not 100% 
sure about why it does'nt work, im just guessing from the way it _seems_ 
to work. I have read no documentation on this.

If you want it to work before you create an instance, then you can do 
that with
class foo:
@classmethod
def bar(self):
   print "Hello, World!"

or the older (but exactly the same):
class foo:
def bar(self):
   print "Hello, World!"
bar = classmethod(bar)

>thanks in advance,
>
>-Ivan
>
>  
>
HTH,
Peter

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Re: How is wxWindows related to Python?

[Sathyaish]

Thanks, guys.

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Re: Recursive Property of Octal Numbers

[Dan Christensen]

James Stroud <[EMAIL PROTECTED]> writes:

> I'm very curious about what is going on here. I'm sure my curiosity has 
> something to do with ignorance of some fundamental concept of computer 
> science (maybe that 8 is just a vertical infinity?):
>
> py> b = '\xb6'
> py> b[0]
> '\xb6'
> py> b[0][0]
> '\xb6'

Maybe this clarifies things?

>>> b='a'
>>> b[0]
'a'
>>> b[0][0]
'a'
>>> b[0] == b
True

Dan
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Re: Will python never intend to support private, protected and public?

[Bengt Richter]

On 30 Sep 2005 05:23:35 -0700, Paul Rubin  wrote:

>Steven D'Aprano <[EMAIL PROTECTED]> writes:
>> > It's not easy if the base classes change after you check your code in.
>> > You shouldn't need to know about that if it happens.  Modularity, remember?
>> 
>> Yes. And if you are relying on a public method in a class, and somebody
>> dynamically modifies that public method, your code will stop working too.
>
>I'm not talking about dynamic anything.  I'm talking about a normal
>software project where there are multiple people working on the code.
>You write a class and carefully make sure that none of its private
>variables collide with superclasses in modules that it imports.  You
>check in your code and go do something else.  Then the person
>maintaining the superclasses goes and changes how they use their
>private variables.  He doesn't look at your code since his modules
>don't import yours.  But now both your code and his are broken.
>
>> perhaps that mathematical certainty is appropriate for
>> your ICBM control system or nuclear reactor, but it is a needless
>> affectation for (say) a word processor. 
>
>Why on earth would you want to unnecessarily introduce random bugs
>into a word processor or anything else?  And what happened to the
>marketing claims that Python was good for critical applications?
>Maybe I should post your disclaimer every time one of those
>discussions comes up.  "Python is ok for word processors but no good
>for anything important".  Heck, some people think word processors are
>important.

I decided to read this thread today, and I still don't know exactly
what your requirements are for "private" whatevers. No one seems to
have discussed what you could do with properties and __getattribute__
and metaclasses and decorators, yet there are many possibilities
that might satisfy some or maybe all your requirements. I probably
missed something...

Semantically, you seem to be wanting to write a class with methods
accessing a selected subset of "variables" "privately." Obviously
if the class e.g. is C, there are many ways to spell C().private_var
and C.private_var. and self.private_var etc., "self" being only
a conventional spelling for an instance ref in the method context.

What "privately" seems to mean is that within a method using
private_var, you'd still like the code to read self.private_var,
and not be translated to self.__some_kind_of_extreme_mangling_private_var
even if the mangling had vanishing collision probability, like a name
built from a secure hash GUID algorithm, right?

Also, if an outside access to an instance said inst.private_var = 123
that would be ok, and bind a public attribute of that name as usual
without interfering with the methods using the bona fide self.private_var?
Or should it be an attribute error (which would thus leak the name even
if it didn't make access possible).

I take it that a clever subclassing trick (like a post somewhere in this thread
showed) should not provide access, but how about the inspect module?
Or an expression like instance.__dict__[1] if that was the sneaky spelling
of instance.private_var? (note that integers are not allowed for instance 
attributes,
even via get/setattr. (BTW & OTOH, interestingly type.__setattribute__(cls, 
att) allows integer att)
Where do you want to draw the line?
 
I'm not trying to be provocative, just to get the requirements defined ;-)

What if you could define a class something like

class C(object):
# privatize factory makes callable to make the changes and clean up 
after itself
__metaclass__ = privatize(method_foo='private_var1 pv2', 
method_bar='pv2')
...

and have method_foo access self.private_var1 and self.pv2 as effectively 
private variables,
and method_bar only self.pv2 and everything else work as usual? Would that meet 
your
requirements? I'm not sure I could do this with just a tricky metaclass, but I 
am pretty
sure if you allowed byte-code-munging decoration calls from the metaclass to 
mess with
method_foo and method_bar (as specified in the privatize factory call args), I 
could.

I think I would collect the private variable names and enumerate them to 
produce integer "names"
for use in accessing the values via self.__dict__[integer_name].

The byte-code munging would then translate accesses to the selected names would 
be translated
to use the appropriate subscript constant integer_names (which would be added 
to the method function
constant list as necessary) and you would have .e.g.
LOAD_FAST0 (self)
LOAD_ATTR1 (__dict__)
LOAD_CONST   1 (1)
BINARY_SUBSCR

in place of say
LOAD_FAST0 (self)
LOAD_ATTR1 (pv2)


i.e., _SUBSCR ops instead of _ATTR ops, and analogously for STORE_ATTR and 
STORE_SUBSCR,
(obviously just done to the method variable accesses specified in the privatize 
factory call).

Alternatively, the metaclass could creat

Re: What encoding is used when initializing sys.argv?

[Tim Roberts]

Neil Hodgson <[EMAIL PROTECTED]> wrote:
>
>Petr Prikryl:
>
>> ... I have discovered that
>> I do not understand what encoding should be used
>> to convert the sys.argv into unicode.
>
>Martin mentioned CP_ACP. In Python on Windows, this can be accessed 
>as the "mbcs" codec.
>
>import sys
>print repr(sys.argv[1])
>print repr(unicode(sys.argv[1], "mbcs"))
>
>C:\bin>python glurp.py abcߕ
>'abc\xdf\x95'
>u'abc\xdf\u2022'

There's another entry in my "keep this post forever" file.
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Re: Background process for ssh port forwarding

[Fredrik Lundh]

Jesse Rosenthal wrote:

> If I end this with 'connection.interact()', I will end up logged in to the
> forwarding server. But what I really want is to go on and run rsync to
> localhost port 2022, which will forward to my_server port 22. So, how can
> I put the ssh connection I set up in hostforward() in the background?
> I need to make sure that connection is made before I can run the rsync
> command.

$ man ssh

...

 -f  Requests ssh to go to background just before command execution.
 This is useful if ssh is going to ask for passwords or
 passphrases, but the user wants it in the background.  This
 implies -n.  The recommended way to start X11 programs at a
 remote site is with something like ssh -f host xterm.

...





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