Mailman 3 December 2006 - Python-Dev

help for a noob - version for a sharp ARM
by David Boddie 09 Dec '06

09 Dec '06

On Fri Dec 8 08:07:16 CET 2006, Josiah Carlson wrote: > a Fred <fghaibach at comcast.net> wrote: > > > > I'm looking for advice on stripping down Python for an SBC to run Numpy > > and Scipy. I have the following notes on the system > > > > We have code that requires recent versions of Numpy and Scipy. > > The processor is a 32 bit Sharp ARM Sharp LH7A404 32 bit ARM922TDMI with > > 32MB of SDRAM. > > 512 MB flash disk - but 400 MB is reserved for data > > The OS is Linux > > only a tty interface is used. > > > > Does anyone have a feel as to whether Python for Arm is the correct > > starting point? > > Sounds like plenty of muscle to handle Python certain domain number > crunching problems. It appears that this ARM variant doesn't have a floating point coprocessor. http://www.sharpsma.com/Page.aspx/americas/en/part/LH7A404/ I hope we're dealing with those problem domains here. ;-) > > What modules can I safely add/strip out? > > Most every C module you don't need. You can also compile without > unicode. I believe you can more or less toss everything except for the > base python binary and the pythonxy.so (or pythonxy.dll) for your > platform, but I am most likely wrong. I found that Python tries to import various modules when it starts up, so you might want to be a bit conservative with the ones you discard. However, if the target platform doesn't have libraries that various extension modules require then there's clearly no point in deploying those extensions. There are lots of irrelevant modules (for your application, at least) in the standard library. Anything that's platform-specific can go, apart from any Linux-specific modules, obviously, and even those might be unnecessary. I'm not sure if it's possible to automatically strip out Tkinter (lib-tk) and IDLE (idlelib), but it's probably worth doing so in your case. I should return to my own experiments and do all that again in a systematic way, just to see what can be removed. > My (awful) suggestion: start with > a Python installation in some user path, like ~/python . Toss > everything and start adding things that it complains about until it > starts working again. Or there's that approach. A module dependency graph would be useful to have, or even just a list of modules that are required to get to the interactive prompt. It might also be worthwhile compiling all the pure Python modules to bytecode and discarding the sources, but only if the compiled code is smaller, of course. > > Will Python take more than 5-6 seconds to load? > > I have previously gotten dos versions of Python (I think 1.5 or 1.4) to > load on a 486 sx 33 with 8 megs of ram in a couple seconds. You > shouldn't have issues with startup on an ARM. Less than a second, I would imagine. Extension modules will also increase the loading time, especially if they need to be perform some tasks when they start. > > Will old Python releases, like 1.5.x, work with newer Numpy and Scipy? > > I don't know. But you should be able to remove unused portions of > Python for your platform. There are somewhat recent posts in this > mailing lists about embedded systems and Python. Others may be able to > help you more. It should be possible to compile a version of Python for the ARM922TDMI that uses Thumb instructions. These are 16 bit instructions that are expanded on the fly so that they can be processed by the CPU as normal 32 bit wide instructions. This doesn't mean that the resulting executable and libraries will be half the size that they would have been when compiled normally, but you may be able to save some storage space that way. I have no idea whether this trick will help you save RAM as well. David

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Re: [Python-Dev] [Python-checkins] MSI being downloaded 10x more than all otherfiles?!
by "Martin v. Löwis" 09 Dec '06

09 Dec '06

Terry Reedy schrieb: > How do the first two months downloads of 2.5.msi compare to 2.4.msi? It's actually publicly available: http://www.python.org/webstats/ Regards, Martin

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Re: [Python-Dev] [Python-checkins] MSI being downloaded 10x more than all otherfiles?!
by Guido van Rossum 08 Dec '06

08 Dec '06

That was the month of October. If people believe these numbers are real, we're doing great!!! On 12/8/06, Fredrik Lundh <fredrik(a)pythonware.com> wrote: > Guido van Rossum wrote: > > >I looked through the python.org web stats (as I usually do when > > preparing for a keynote) and discovered that > > /ftp/python/2.5/python-2.5.msi is by far the top download -- 271,971 > > hits, more than 5x the next one, /ftp/python/2.5/Python-2.5.tgz > > (47,898 hits). > > over what period ? > > fwiw, I've seen a 2.5x ratio for my stuff over the last year; I've always assumed > that most people on other platforms are simply getting their stuff from the vendor's > standard repository. > > </F> > > > > _______________________________________________ > Python-checkins mailing list > Python-checkins(a)python.org > http://mail.python.org/mailman/listinfo/python-checkins > -- --Guido van Rossum (home page: http://www.python.org/~guido/)

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a feature i'd like to see in python #2: indexing of match objects
by Ben Wing 08 Dec '06

08 Dec '06

this one is fairly simple. if `m' is a match object, i'd like to be able to write m[1] instead of m.group(1). (similarly, m[:] should return the same as list(m.groups()).) this would remove some of the verbosity of regexp code, with probably a net gain in readability; certainly no loss. ben

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help for a noob - version for a sharp ARM
by a Fred 08 Dec '06

08 Dec '06

I'm looking for advice on stripping down Python for an SBC to run Numpy and Scipy. I have the following notes on the system We have code that requires recent versions of Numpy and Scipy. The processor is a 32 bit Sharp ARM Sharp LH7A404 32 bit ARM922TDMI with 32MB of SDRAM. 512 MB flash disk - but 400 MB is reserved for data The OS is Linux only a tty interface is used. Does anyone have a feel as to whether Python for Arm is the correct starting point? What modules can I safely add/strip out? Will Python take more than 5-6 seconds to load? Will old Python releases, like 1.5.x, work with newer Numpy and Scipy? Thanks! a Fred

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Re: [Python-Dev] Spam and semi-spam and neo-spam
by Kurt B. Kaiser 08 Dec '06

08 Dec '06

"Karen Treanor" <krwtreanor(a)ozemail.com.au> writes: > More and more people seem to be having a selection of email addresses, > some for general contact, some for business, and one private one for > only a select few contacts. This isn't possible in business, as your > email address is by necessity public, it has to be. > > I recently tried replying to a piece of spam and clicked on the opt > out button, but the sent item just bounced back as undeliverable. > Yahoo has a Spam tag facility but that only works for 'fixed' sites, > these random rotating ones each come in as discreet items and there's > no way to block them at source. Don't ever do that! 1. The majority of these links are bogus. 2. The majority of the rest use your click to verify you are a working email address. Then they sell the 'verified' list and you get even more spam. 3. Some of the links are fraudulent: they are phishing links which don't go where you expect, i.e. they use special characters to fool you. The result is you are directed to a site which infects your computer. -- KBK

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Re: [Python-Dev] RealClearPolitics - Articles - Exit Rumsfeld, Smiling
by Kurt B. Kaiser 08 Dec '06

08 Dec '06

"Karen Treanor" <krwtreanor(a)ozemail.com.au> writes: > Unfortunately this won't work for me, not by clicking on it or by > cutting and pasting it. The url below is wrapped, I assume you fixed the wrap? > > -----Original Message----- From: Kurt B. Kaiser [mailto:kbk@shore.net] >Sent: Friday, 8 December 2006 4:57 AM To: cwkaiser(a)fastmail.fm; Karen >Treanor Subject: RealClearPolitics - Articles - Exit Rumsfeld, Smiling > > <URL: > http://www.realclearpolitics.com/articles/2006/12/exit_rumsfeld_smilin > g.html >> -- KBK

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Threading, atexit, and logging
by "Martin v. Löwis" 08 Dec '06

08 Dec '06

In bug #1566280 somebody reported that he gets an exception where the logging module tries to write to closed file descriptor. Upon investigation, it turns out that the file descriptor is closed because the logging atexit handler is invoked. This is surprising, as the program is far from exiting at this point. Investigating further, I found that the logging atexit handler is registered *after* the threading atexit handler, so it gets invoked *before* the threading's atexit. Now, threading's atexit is the one that keeps the application running, by waiting for all non-daemon threads to shut down. As this application does all its work in non-daemon threads, it keeps running for quite a while - except that the logging module gives errors. The real problem here is that atexit handlers are invoked even though the program logically doesn't exit, yet (it's not just that the threading atexit is invoked after logging atexit - this could happen to any atexit handler that gets registered). I added a patch to this report which makes the MainThread __exitfunc a sys.exitfunc, chaining what is there already. This will work fine for atexit (as atexit is still imported explicitly to register its sys.exitfunc), but it might break if other applications still insist on installing a sys.exitfunc. What do you think about this approach? Regards, Martin P.S. There is another issue reported about the interpreter crashing; I haven't been able to reproduce this, yet.

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features i'd like [Python 3000?] ... #4: interpolated strings ala perl
by Ben Wing 08 Dec '06

08 Dec '06

sorry to be casting multiple ideas at once to the list. i've been looking into other languages recently and reading the recent PEP's and such and it's helped crystallize ideas about what could be better about python. i see in PEP 3101 that there's some work going on to fix up the string formatting capabilities of python. it looks good to me but it still doesn't really address the lack of a simple interpolated string mechanism, as in perl or ruby. i find myself constantly writing stuff like text="Family: %s" % self.name maybe_errout("%s, line %s: %s\n" % (title, lineno, errstr)) def __str__(self): return "CCGFeatval(%s, parents=%s, licensing=%s)" % ( (self.name, self.parents, self.licensing)) and lots of similar examples that are just crying out for perl-style variable interpolation. the proposals in PEP 3101 don't help much; i'd get instead something like maybe_errout("{0}, line {1}: {2}\n".format(title, lineno, errstr)) which isn't any better than the current % notation, or something like maybe_errout("{title}, line {lineno}: {errstr}\n".format(title=title, lineno=lineno, errstr=errstr)) where i have to repeat each interpolated variable three times. yuck yuck yuck. how about something nice like maybe_errout(i"[title], line [lineno]: [errstr]\n") or (with the first example above) text=i"Family: [self.name]" or (third example above) def __str__(self): return i"CCGFeatval([self.name], parents=[self.parents], licensing=[self.licensing])" the advantage of these is the same as for all such interpolations: the interpolated variable is logically placed exactly where it will be substituted, rather than somewhere else, with the brain needing to do some additional cross-referencing. `i' in front of a string indicates an "interpolated" string just like `r' in the same position means "raw string". if you think this is too invisible, you could maybe use `in' or something easier to see. however, i could see a case being made for combining both `i' and `r' on the same string, and so using a single letter seems to make the most sense. formatting params can follow, e.g. print i"The value of [stock[x]] is [stockval[x]:%6.2f]" some comments: 1. i suggest brackets here so as to parallel but not interfere with PEP 3101, which uses braces; PEP 3101 is somewhat orthogonal to this proposal and the two might want to coexist. i think using something like brackets or braces is better than perl's $ convention (it explicitly indicates the boundaries of the interpolation) and simpler than ruby's #{...} or make's ${...}; since strings are only interpolated if you specifically indicate this, there's less need to use funny characters to avoid accidental interpolation. 2. as shown in the last example, format specifiers can be added to an interpolation, as in PEP 3101. maybe the % is unnecessary. 3. as shown in various examples, things other than just straight variables can be interpolated. the above examples include array/hash references and object attributes. it's not exactly clear what should and shouldn't be allowed. one possibility is just to allow an arbitrary expression. PEP 3101 isn't going to do this because it's working on existing strings (including ones that may come from the user), and so allowing arbitrary expressions could lead to security holes. but here, we're talking about immediate strings, so security holes of this sort should not a concern. 4. the semantics of an interpolated string are exactly that of a series of string concatenations, e.g. return i"CCGFeatval([self.name], parents=[self.parents], licensing=[self.licensing])" is equivalent to return "CCGFeatval(" + self.name + ", parents=" + self.parents + ", licensing=" + self.licensing + ")" ben

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Adding C99 bool to struct module
by "Martin v. Löwis" 08 Dec '06

08 Dec '06

#1610575 suggests to introduce the 't' code to support the _Bool type where available, and uses char if it isn't available. Any objections to adding it? Regards, Martin

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