of the documentation about these
functions, too. They are not just like popen.
Donn Cave, [EMAIL PROTECTED]
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C, G = (H, A, B, C, D, E, F, G, W[1], 0x71374491)
...
2. The OOP way: each object has the appropriate function
that modifies its content value. That looks like a
big waste of time to me, but I mention it for conceptual
completeness.
Donn Cave, [EMAIL PROTECTED]
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is has a little potential to mislead. Bourne shell
syntax is naturally "shell-like", but it is not "simple" -
as grammars go, it's a notorious mess. In theory, someone
could certainly write Python code to accurately parse Bourne
shell statements, but that doesn't ap
#x27;ad hoc'-polymorphism.
Or 'bogus'-polymorphism.
Donn Cave, [EMAIL PROTECTED]
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Quoth Mike Meyer <[EMAIL PROTECTED]>:
| "los" <[EMAIL PROTECTED]> writes:
| > I'm trying to create a program similar to that of Google's desktop that
| > will crawl through the hard drive and index files. I have written the
| > program and as of now I just put the thread to sleep for 1 second afte
e hard-coded octal bitmask definitions, including
S_IFDIR = 004.
Check it out. Try to use that value the way they're using it,
in C and in Python, and print out all the values involved.
At worst, if C comes out wrong too, you may have a question
that the vendor will be more likely to respond to.
Donn Cave, [EMAIL PROTECTED]
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nce to set
up the initial connection.
Donn Cave, [EMAIL PROTECTED]
--
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ue to write output, since it's truly a rare application
that checks its output (especially since it's usually buffered.)
The SIGPIPE signal just aborts the program. Not really very
much like EOF at all.
You could install your own handler, but it would probably make
about as much sense
t modern platforms, sh will have a pretty
good programming feature set, and will be more reliable
(especially if it isn't just ksh by another name.)
Donn Cave, [EMAIL PROTECTED]
--
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In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] (Cameron Laird)
wrote:
> In article <[EMAIL PROTECTED]>,
> Donn Cave <[EMAIL PROTECTED]> wrote:
> .
> .
> .
> >Meanwhile, it might be wor
In article <[EMAIL PROTECTED]>,
Thorsten Kampe <[EMAIL PROTECTED]> wrote:
> * Cameron Laird (2005-06-02 18:08 +0100)
> > In article <[EMAIL PROTECTED]>,
> > Donn Cave <[EMAIL PROTECTED]> wrote:
> >>Meanwhile, it might be worthwhile to reconsider
ksh to pure python... I thought
> that I could re-use some stufff, but I guest I'm going to translate
> everything...
Right, that's true - more generally, no process can modify
another's environment.
Donn Cave, [EMAIL PROTECTED]
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n. It always invokes the
shell.
The no-shell alternatives are spawnv (instead of
system) and the popen2 family (given a sequence
of strings.)
Donn Cave, [EMAIL PROTECTED]
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esses", after the popen() paragraph above tells
you how to do it (using the better term "exit status".)
Or one may look at the source.
Donn Cave, [EMAIL PROTECTED]
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trol, the choice between two ways to take
the boolean sense of a loop control is really based on some
logical premises, which we can reconsider if it's productive
to do so. I prefer this to fantasies about changing the language,
your mileage may vary.
Donn Cave, [EMAIL PROTECTED]
--
h
n't expect this to work reliably with
random objects. The price we pay for the notion is mostly
in the "fix" for float repr, which now displays the float
in all its imprecise glory and routinely confounds people
who don't understand what that's about.
Donn Cave, [EMAIL PROTECTED]
--
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d in the format that is most readily processed,
and it will omit extraneous information. Are we saying anything other
than this?
Donn Cave, [EMAIL PROTECTED]
--
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In article <[EMAIL PROTECTED]>,
"John Roth" <[EMAIL PROTECTED]> wrote:
> "Donn Cave" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> > Quoth "John Roth" <[EMAIL PROTECTED]>:
> > ...
> > | str() sho
ly needed. If you look at C code, at least in my experience the
"until" loop is quite rarely used. (I don't see it once in the source
to Python 2.4, for example.) Meanwhile, the "while True" (or "while 1")
idiom is very familiar to Python programmers (just as t
Quoth Peter Otten <[EMAIL PROTECTED]>:
...
| 'until' in C is actually
|
| do
| statement
| while (expression);
Oops. Well, QED - I sure don't need it often.
Donn Cave, [EMAIL PROTECTED]
--
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n reasonably argue that steel toed boots
prevent injuries to the toe, without having to prove that
they withstand a welding torch, a nuclear blast, etc.
Donn Cave, [EMAIL PROTECTED]
--
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points
of articulation and more things that aren't obvious to the person
making the changes. If that's flexibility, you can have it.
Donn Cave, [EMAIL PROTECTED]
--
http://mail.python.org/mailman/listinfo/python-list
ar or two ago. I don't see
how it could ever get anywhere without offending a lot of the
Python crowd, however well designed, so I can see why someone
might try to sneak it past by pretending it has nothing to do
with types. But he didn't -- look at the examples, I think he
rather overst
onse to, and I don't know what
that was supposed to mean, but Haskell's type system addresses
just what we all would expect, the structural consistency of the
program in terms of data types. It doesn't generally prevent data
errors or correct your misunderstanding of an algorithm or in
general avoid every kind of error. What it does, though, it does
rather well.
Donn Cave, [EMAIL PROTECTED]
--
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#x27;s reprimands about your code errors,
or nagging about warnings? Maybe the language implementation's
job has as much to do with working around our feelings as anything
else.
Donn Cave, [EMAIL PROTECTED]
--
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In article <[EMAIL PROTECTED]>,
Steve Holden <[EMAIL PROTECTED]> wrote:
> Donn Cave wrote:
> > Someday we will look at "variables" like we look at goto.
> >
> How very functional. I believe some people naturally think in terms of
> state tran
uch else in this thread. Certainly up to you, but you wouldn't be
in a very good position to be drawing weird inferences as above.
Or you see original conception of the program as so inherently
suspect, that random errors introduced during implementation can
reasonably be seen as helpfu
lems with the procedural/imperative programming
model, and we can establish that it was already hated and on its
way out by the late 90's? How about OOP? Already on its way out
by the time Python 1.0 hit the streets?
The thing that allows us to be so smug about the follies of the
past, is that we can pretend everyone knew better.
Donn Cave, [EMAIL PROTECTED]
--
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for it, other than the obvious -
either always flush, or wrap an explicit close in its own exception
handler.
Donn Cave, [EMAIL PROTECTED]
--
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t a lot of work to read data with operating system functions
that are compatible with select - os.read(), socket.recv() - and
break it up into lines on your own, and this completely and efficiently
resolves the problem.
I haven't looked at your code.
Donn Cave, [EMAIL PROTECTED]
--
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ference counting allocation scheme
will be useful. In particular, you need a fairly good grasp of
what a "reference" is.
Donn Cave, [EMAIL PROTECTED]
--
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dy RMS$ function or two so it gets done in
a consistent way. This allows the command line interface to
interact with the user in a little more transparent way, since
the input seen by the program is congruent with what the user
typed in. E.g., "rename *.jpeg *.jpg" is trivial on VMS,
im
In article <[EMAIL PROTECTED]>,
Grant Edwards <[EMAIL PROTECTED]> wrote:
> On 2007-04-26, Donn Cave <[EMAIL PROTECTED]> wrote:
>
> >> One possible way to work around this is to get the raw command line
> >> and do the shell expansions ourselves from wi
ometimes to the
point of what seems like willful blindness to the deficiencies of
a favorite programming language.
If we have a sound language proposal backed by a compelling need,
fine, but don't add a great burden to the language for the sake of
great plans for Nepalese grade school programmers.
Donn Cave, [EMAIL PROTECTED]
--
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ed towards the end. Yes, it's the Laura Creighton
article again:
http://groups.google.com/group/comp.lang.python/msg/2de5e1c8384c0360
Donn Cave, [EMAIL PROTECTED]
--
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In article <[EMAIL PROTECTED]>,
Erik Max Francis <[EMAIL PROTECTED]> wrote:
> Donn Cave wrote:
>
> > Anyone who finds this surprising, might enjoy reading this
> > article from the time several years ago when the feature
> > was being considered. When you
In article <[EMAIL PROTECTED]>,
Erik Max Francis <[EMAIL PROTECTED]> wrote:
> Donn Cave wrote:
>
> > Not that it is of no historical interest to review all these
> > reasonable arguments, but allow me to restore the context quote
> > from my follow-up:
he way we render
objects as text strings, a priori. If there is any such thing, it
depends completely on the context. To invite the author of an object
to devise a text rendition that will be humane (friendly, readable
or whatever) is to waste his or her time. There are better ways to
conceive of this str/repr distinction, and they've been discussed
to death. python.org documentation will probably never be fixed.
Donn Cave, [EMAIL PROTECTED]
--
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an you
retrieve other fields that way? Does the one you're looking for appear
in the data if you get the whole header, for example with 'RFC822.HEADER'?
It certainly does in my Python IMAP client, and this would have at least
helped you refine your question.
Donn Cave
--
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fer to use a
> different thread for reading its output.
Right - `I used threads to solve my problem, and now I have two
problems.' It can work for some variations on this problem, but
not the majority of them.
Donn Cave, [EMAIL PROTECTED]
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In article <[EMAIL PROTECTED]>,
"Gabriel Genellina" <[EMAIL PROTECTED]> wrote:
> En Fri, 02 Mar 2007 14:38:59 -0300, Donn Cave <[EMAIL PROTECTED]>
> escribió:
>
> > In article <[EMAIL PROTECTED]>,
> > "Gabriel Genellina"
index method. This suggests a missing
> method, does it not? Who has not done this?
> Name yourself!
I am pleased to find myself in this company. My name is
Donn Cave. I have been using Python since version 1.1,
though frankly I haven't used it a lot in recent years.
I have a confess
ngly that
> this shouldn't be understood in terms of type similarities.
Well, yes - consider for example the "tm" tuple returned
from time.localtime() - it's all integers, but heterogeneous
as could be - tm[0] is Year, tm[1] is Month, etc., and it
turns out that not on
In article <[EMAIL PROTECTED]>,
"Hendrik van Rooyen" <[EMAIL PROTECTED]> wrote:
> "Donn Cave" <[EMAIL PROTECTED]> wrote:
>
> >
> > Well, yes - consider for example the "tm" tuple returned
> > from time.localtime() - it
rameter binding should
be implemented, so you could say
dotted = string.join('.')
...
v = dotted(['comp', 'lang', 'python'])
As you probably well know, that isn't my idea, it's a common
functional programming language idiom.
Donn Cave, [EMAIL PROTECTED]
--
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appropriate one.
>
> Use os.open with the O_EXCL flag; will fail if the other process has the
> file still open (and will fail if another process is reading the file, too,
> not just if someone is writing).
O_EXCL fails if the file exists at all - whether closed or open.
Donn Cave, [EMAIL PROTECTED]
--
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In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Nick Maclaren) wrote:
> In article <[EMAIL PROTECTED]>,
> Donn Cave <[EMAIL PROTECTED]> writes:
> |> In article <[EMAIL PROTECTED]>,
> |> "Gabriel Genellina" <[EMAIL PROTECTED]> wro
In article <[EMAIL PROTECTED]>,
James Stroud <[EMAIL PROTECTED]> wrote:
...
> Paddy wrote:'
> > Frank,
> > IPython is great, but it is not a replacement for a shell like bash. If
> > you have a Linux system then you still need to know the rudiments of
> > bash
>
> Or better yet, csh. ;)
Careful
str() to force data to string type (that's
what I mean by conversion.) If the object can't sensibly be
converted to string type, then normally __str__ is omitted, and
defaults to __repr__.
Donn Cave, [EMAIL PROTECTED]
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't have signal handlers,
sounds like a horrible idea to me. If your code has a signal
handler for SIGCHLD, try to get rid of that - the handler itself
is causing your problem.
OO (Object Oriented?) doesn't have anything to do with the problem,
that I can think of.
Donn Cave, [EMAIL PROTECTED]
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les do not fulfill certain
> critereia causing so_somehting() to return before the entire file is
> processed.
Most programming environments don't have this problem, though.
If you like, your program can undo what Python does:
signal.signal(signal.SIGPIPE, signal.SIG_DFL)
for file
gument handling, no.
We know that without having to know anything about t, and not
much about f. This is characteristic of tuple applications.
Donn Cave, [EMAIL PROTECTED]
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In article <[EMAIL PROTECTED]>,
Paul Rubin <http://[EMAIL PROTECTED]> wrote:
> Donn Cave <[EMAIL PROTECTED]> writes:
> > If t is a valid argument tuple for function f, then can t[1:]
> > also be a valid argument tuple for function f?
> >
> > Fo
gt; i'm struggling to figure this out. can you recommend any possible
> methods of preventing this? for instance, could acquiring a thread
> lock before calling popen solve the problem?
No.
Did you look at the text of the post you responded to here?
What do you think about that advice? Do
In article <[EMAIL PROTECTED]>,
Paul Rubin <http://[EMAIL PROTECTED]> wrote:
> Donn Cave <[EMAIL PROTECTED]> writes:
> > Unpredictable? How do you manage to write functions in this case?
> > Are all your formal parameter lists like (*a), with logic to d
d that restart loop, actually reading
one line at a time and appending to the line list. I'm not
sure that's totally bulletproof - probably will work, but
if you need a sure thing, I would go to UNIX I/O (posix.read),
in a loop, and then split the concatenated results by newline.
Or, of course if you could shut down the signals...
Donn Cave, [EMAIL PROTECTED]
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Quoth Paul Rubin <http://[EMAIL PROTECTED]>:
| Donn Cave <[EMAIL PROTECTED]> writes:
| > What this proves is that you can implement
| > an argument list at run time, but it by no means changes the
| > nature of the argument list as a sequence.
|
| Right, it's treated a
gh the loopback
interface anyway, invariably regardless of host network implementation?
Donn Cave, [EMAIL PROTECTED]
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someone who learns Python concepts
in terms of explanations like `boxes' or `pointers' or whatnot
is at some disadvantage while that lasts, like translating a
foreign language to your own instead of attaching meaning
directly.
Donn Cave, [EMAIL PROTECTED]
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oard interrupt?
You might try posix.setsid(), from the child fork.
The object is to get the child fork out of the foreground
process group for the Berkeley terminal driver. This defines
who gets signals, when they originate in terminal control keys.
Donn Cave, [EMAIL PROTECTED]
--
http://ma
uld cheerfully accept this,
given the meager and clumsy support for static typing in languages
like C++, but today, it makes me appreciate Haskell's potential
for complex projects.
Donn Cave, [EMAIL PROTECTED]
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rony because there's no way to know when the data is
ready, and 3rd rate I/O because afterwards you still have the
copying to do. I don't see even this much in asyncore.py, but
I just gave it a glance.
thanks,
Donn Cave, [EMAIL PROTECTED]
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t does support "asynchronous, blocking" with
aio -- as VAX/VMS did (and presumably still does), with event
flags.
Donn Cave, [EMAIL PROTECTED]
--
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ed pipe. When you read from one,
you get end of file, i.e., a normal return with 0 bytes.
When you test it, make sure to try a configuration with more
than one child process. Since the parent holds the write end
of the pipe, subsequently forked child processes could easily
inherit it, and they&#x
tify the backup
error unit, if the command line parameter option isn't available
for some reason.
Donn Cave, [EMAIL PROTECTED]
--
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ome of the maintenance issues, since at least you can upgrade on
your own schedule, but of course it has its costs too. Anyone who
might be thinking about using Python for an application should
seriously think about this.
Donn Cave, [EMAIL PROTECTED]
--
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ation is a lot more fun in some ways,
but I think if you were to apply a sort of conspiracy analysis
to the situation - "who benefits from language change" - this
would be a couple items down on the list of motivations.
Donn Cave, [EMAIL PROTECTED]
--
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27;t imagine how you could be
convinced of this. Changes to Python in 3.0 won't satisfy
the continuing "need" for change thereafter.
Donn Cave, [EMAIL PROTECTED]
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hey are not better known'
If English isn't your 1st language, you deserve a lot of credit for your
mastery of it, but you need a better dictionary.
Donn Cave, [EMAIL PROTECTED]
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ket, dict, whatever?
A sort of generic solution might be to follow str's behavior
with respect to '__str__', extending it to fall back to repr()
whatever goes wrong.
def xtr(a):
try:
return str(a)
except:
return repr(a)
...
27;t see how this is possible if os.path.exists(pth) returns
> True, why is it os.execve() has problems finding it.
I haven't used chroot enough to know all the pitfalls, but
here's one guess: suppose the CGI script file `pth' might
actually be a script, with a `#!' top line t
t;> resulting in the desired result or a typecasting error otherwise.
> >> Furthermore, it could do it more efficiently than a developer having to
> >> put conditional code at the beginning of traditionally typecasting
> >> functions.
I know awk works a bit like that, maybe Perl? but it's
surely way out of place in Python.
Donn Cave, [EMAIL PROTECTED]
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is not connected')
>
> This is despite the client waiting on a socket.recv() statement. Is
> the client really not connected, or is the server unaware of the
> connection? And how do I fix this?
You can either connect() as well as bind(), or use
sendto(data, file)
Do
y go both ways. I was a little
surprised by this, and have not been able to scare up any
explicit documentation, but the only example program I
could find for two-way UNIX domain datagram IPC, uses two
sockets, not one -
http://docs.hp.com/en/B2355-90136/ch07s06.html
Donn Cave, [EMAIL PROTECTED]
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; value, before you can assume that
you got the data you asked for. I would suggest that you print
these values out somewhere, it will put you in a position where
you can probably answer your question better than we can.
Donn Cave, [EMAIL PROTECTED]
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ducing strings.
Anyway, it seems unlikely he would get that INVARG error for this
reason. That's an error from the host operating system, not the
interpreter, and it mostly likely refers to the file descriptor.
Since it works for me, I guess his problem is basically this:
|> (python 2.4
servers, but there it's email net protocol data, POP or IMAP. If
Mahogany has been using this format for `local' folders (i.e., via
filesystem), I think that may have been kind of poor judgement on the
part of its developers.
Donn Cave, [EMAIL PROTECTED]
--
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Quoth "David Isaac" <[EMAIL PROTECTED]>:
| Donn Cave, [EMAIL PROTECTED]
|> I suppose it isn't supported by the mailbox module basically because
|> it isn't all that commonly encountered. It may be more common on mail
|> servers, but there it's email net pro
e places
where it may be better to write
if not expr:
than
if expr is None:
or worse yet,
if expr == False:
That's what I think, anyway.
Donn Cave, [EMAIL PROTECTED]
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gs, or open the output file some other way that
creates a file object and use its fileno() function. Flush
stdout before each dup2().
To revert back to the original stdout, you will want a
copy of that stream, which you can get with the os.dup()
function, prior to redirection. All the left over file
than a pipe, but you can probably
get something going with openpty or forkpty from
the os/posix module, or there may still be 3rd
party packages for this.
Donn Cave, [EMAIL PROTECTED]
--
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exc_traceback = None), the applications
used a terminal graphics library, like curses, and I often
depended on finalization (__del__) to run the "close" rendering
for a graphic element. Worked fine until an exception, so I
add this precaution to every I/O flush.
Donn Cave, [EMAIL PROTECTED]
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ents fcntl.flock() with fcntl(2),
I guess on the theory that you can't have enough brain
damage. The worst case would be if Python's configure
missed a bona fide flock(2), which is unlikely but may
be worth checking if you use flock(2) for a reason.
Donn Cave, [EMAIL PROTECTED]
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