🌐 Mailman 3 July 2011 - Python-list - python.org

Re: Why won't this decorator work?
by John Salerno July 3, 2011

July 3, 2011

On Jul 2, 12:33 pm, MRAB <pyt...(a)mrabarnett.plus.com> wrote: > On 02/07/2011 17:56, John Salerno wrote: > > > > > > > > > > > I thought I had finally grasped decorators, but the error I'm getting > > ('str' type is not callable) is confusing me. Here is my code. Also, > > the commented sentence is from the Python docs, which says it doesn't > > even need to be callable, if that matters. I also commented out a few > > things in the move method. They were just to see if it would work, but > > those lines raised even more errors! > > > import random > > > #space = 0 > > > def move(roll): > > # global space > > # space += roll > > return 'You moved to space {0}.'.format(roll) > > > @move > > def roll_die(): > > return random.randint(1, 6) > > > # The return value of the decorator need not be callable > > # roll_die = move(roll_die) > > > I tried running the command "roll_die()" and I get the error message. > > > Thanks. > > A decorator should return a callable. > > This: > > @move > def roll_die(): > return random.randint(1, 6) > > is equivalent to this: > > def roll_die(): > return random.randint(1, 6) > > roll_die = move(roll_die) > > You should be defining a function (a callable) and then passing it to a > decorator which returns a callable. > > As it is, you're defining a function and then passing it to a decorator > which is returning a string. Strings aren't callable. But why does the documentation say "The return value of the decorator need not be callable"? And why, if I remove the decorator and just leave the two functions as if, does the call to move(roll_die()) work? Isn't that what the decorator syntax is essentially doing?

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Re: Inexplicable behavior in simple example of a set in a class
by Saqib Ali July 3, 2011

July 3, 2011

> Instance variables are properly created in the __init__() > initializer method, *not* directly in the class body. > > Your class would be correctly rewritten as: > > class MyClass2(object): > def __init__(self): > self.mySet = sets.Set(range(1,10)) > > def clearSet(self): > # ...rest same as before... Thanks Chris. That was certainly very helpful!! So just out of curiosity, why does it work as I had expected when the member contains an integer, but not when the member contains a set?

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Re: The end to all language wars and the great unity API to come!
by rantingrick July 3, 2011

July 3, 2011

On Jul 2, 6:38 pm, Chris Angelico <ros...(a)gmail.com> wrote: [...] > It takes work to suit your API to a different language. Let's take GNU > Aspell as an example; [...] Should the Aspell team offer bindings for every > known language? In your post, you recommend supporting a minimum of > three. Which three? Why? No. Aspell should offer bindings for THE "Unity API" and the respective "abstraction communities" are then responsible for maintaining a plugin for their "abstraction" into THE Unity API. > I'm a great fan of an obscure language named Pike. Do I expect Aspell > to be available for Pike? You should expect this. However if it is not available you cannot blame Aspell for that! No, you MUST blame the pike community. But first we have to blame EVERYONE because the unity API does not exist... not yet! Or at least the mindset for it does not exists. > No, and I wouldn't even if your > three-language rule were followed. My rule is for "unlimited unity" not "limited numbers". > So how can I implement a > spellchecker in my code? By writing glue. I'll write a module that > exposes the C++ API to Pike. (This is actually a real example. I ended > up writing my aspell hook to run as a separate process for isolation's > sake, but it comes to the same thing.) Yeah and they have a name for that... "reinventing the wheel". An end user should NEVER EVER have to write glue code so their "abstraction of choice" can be used to to script an API. That's like expecting automobile drivers to build a car from a hunk of iron ore every time! No, we have car manufactures who specialize in building cars. However the respective programming language communities are all oblivious to the greater picture. An iteration is an iteration whether you use the "for x in iterable: x.blah()" or the "iterable.each{|x| x.blah}" or WHATEVER syntax you choose to use. It all boils down to the same 1's and 0's. Can't you see how our own sense of selfish pride is defeating productivity and discovery? Can't you see? It's fine to speak French, or Japanese, or English if you want. But eventually we will need a unifying natural language and likewise a unifying programming language. [Note to community] Actually from now on i want everyone to stop using the words programming and language together. Instead of "X programming language" i want to you say "X abstraction layer". Python programming language --> Python abstraction layer. Ruby programming language --> Ruby abstraction layer. X programming language --> X abstraction layer. You see, we constantly refer to languages as tools, and this mindset is lunacy! All languages compile to 1's and 0's. Languages are not TOOLS they are all ABSTRACTIONS of a single virtual tool AND THAT TOOL IS SOFTWARE!). So stop brainwashing yourselves and others with these foolish descriptors! Begin to focus your mind on unity and standardization. Then and only then can we combine our singular minds into the hive mind.

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Re: The end to all language wars and the great unity API to come!
by rantingrick July 3, 2011

July 3, 2011

On Jul 2, 6:38 pm, Chris Angelico <ros...(a)gmail.com> wrote: [... snip expositions...] > C or C++ bindings will cover most languages. > > Chris Angelico This is pretty much the entire argument, everything else is exposition.

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How does CO_FUTURE_DIVISION compiler flag get propagated?
by Terry July 3, 2011

July 3, 2011

I've built a Python app for the iPhone, http://www.sabonrai.com/PythonMath/. Like embedding Python in another app, it uses PyRun_SimpleString() to execute commands entered by the user. For evaluating expressions, it uses PyEval_EvalCode() with the dictionary from the __main__ module. Future division ("from __future__ import division") works within scripts executed by import or execfile(). However, it does not work when entered interactively in the interpreter like this: >>> from __future__ import division >>> a=2/3 You get classic (integer) division, but if you enter it as follows, you get future (float) division. >>> from __future__ import division;a=2/3 It appears that the CO_FUTURE_DIVISION compiler flag is not being retained in the interpreter so that later commands get compiled without that flag. I found a hint in http://groups.google.com/group/comp.lang.python/browse_thread/thread/13a90a…, but I don't see that PyRun_SimpleStringFlags returns the flags it uses. I guess I could watch for the user to enter the import command but that's really brittle. Thanks.

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Re: poll of filesystem
by Tim Roberts July 2, 2011

July 2, 2011

Belisko Marek <marek.belisko(a)gmail.com> wrote: > >just want to use poll method to get data from /proc file system. Use >simple code for it. Problem is it seems poll return POLLIN flag but >when I try to read data it's always empty. Could be a problem changes >are so fast that print can't print it? Poll doesn't make sense here. The data in /proc/loadavg data is not text data that gets updated periodically. There is no file on disk somewhere called /proc/loadavg. Instead, reading /proc/loadavg causes a call into a kernel driver, and reads data directly from variables stored in the kernel. The data is ALWAYS available. If you want the data once a second, just do it the easy way: import time while True: print open('/proc/loadavg').read() time.sleep(1) -- Tim Roberts, timr(a)probo.com Providenza & Boekelheide, Inc.

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poll of filesystem
by Belisko Marek July 2, 2011

July 2, 2011

Hi, just want to use poll method to get data from /proc file system. Use simple code for it. Problem is it seems poll return POLLIN flag but when I try to read data it's always empty. Could be a problem changes are so fast that print can't print it? Code: #!/usr/bin/python import select from select import POLLIN, POLLERR p = select.poll() fd = open("/proc/loadavg", "r") p.register(fd.fileno(), POLLIN) while True: events = p.poll(1000) if (events == -1): print "timeout" fd0, event = events[0] if (event == POLLIN): print fd.read() Thanks, marek -- as simple and primitive as possible ------------------------------------------------- Marek Belisko - OPEN-NANDRA Freelance Developer Ruska Nova Ves 219 | Presov, 08005 Slovak Republic Tel: +421 915 052 184 skype: marekwhite icq: 290551086 web: http://open-nandra.com

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need to extend this C code so that it initiates this python script (python C api)
by aregee July 2, 2011

July 2, 2011

hi i need help with extending this http://paste.pound-python.org/show/8918/ c code so that it can initiate this python script http://paste.pound-python.org/show/8917/ and export file path here.. btw I tried to run following python code : #include <python2.3/Python.h> //changed this to python2.7/Python.h didn't work the I changed it to Python.h // Error msg : fatal error: Python.h : no file or directory compilation terminated //python-dev and python2.7-dev is already installed. void process_expression(char* filename, int num, char** exp) { FILE* exp_file; // Initialize a global variable for // display of expression results PyRun_SimpleString("x = 0"); // Open and execute the file of // functions to be made available // to user expressions exp_file = fopen(filename, "r"); PyRun_SimpleFile(exp_file, exp); // Iterate through the expressions // and execute them while(num--) { PyRun_SimpleString(*exp++); PyRun_SimpleString("print x"); } } int main(int argc, char** argv) { Py_Initialize(); if(argc != 3) { printf("Usage: %s FILENAME EXPRESSION+\n"); return 1; } process_expression(argv[1], argc - 1, argv + 2); return 0; } thanks aregee Ar

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Re: Does anyone know of a python tapi module
by Alister Ware July 2, 2011

July 2, 2011

On Fri, 01 Jul 2011 14:28:13 -1000, Werner Thie wrote: > On 7/1/11 11:15 AM, Alister Ware wrote: >> The subject probably say is all but to elaborate. >> >> I am looking for a way to communicate with a tapi driver for a PBX so I >> can experiment with creating some CTI (Computer Telephony Integration) >> software. >> >> > I used TAPI since its inception for quite a few projects, but am not > aware of anything pythonic. Attempting to cough up an interface layer I > would resort to using Chris Sells tfx wrapper fro TAPI, which helps a > lot keeping things in check and becoming overly complex. > > HTH, Werner > > http://books.google.com/books?id=3M_mIvtdGqUC&pg=PA82&lpg=PA82&dq=chris +sell+tfx&source=bl&ots=5UhAxbFTym&sig=7hRn0oUbyZsm_yyDvASKD- AT1jo&hl=en&ei=w2UOTsPlBJOisAP57JyrDg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBkQ6AEwAA thanks for taking the time to look Unfortunately I only have a nodding acquaintance with C & don't want togo down that route. looks like I will have to see if I can work something out using the ctypes module --

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Re: poll of filesystem
by Nobody July 2, 2011

July 2, 2011

On Sat, 02 Jul 2011 11:40:46 +0200, Belisko Marek wrote: > just want to use poll method to get data from /proc file system. Use > simple code for it. Problem is it seems poll return POLLIN flag but > when I try to read data it's always empty. Could be a problem changes > are so fast that print can't print it? poll() doesn't work for files; they are always readable. It's meant for pipes, sockets and character devices (ttys, etc). If you're looking for a way to find out when a file has changed, there isn't one (Linux has inotify, but that isn't portable and it doesn't work with /proc). The reason why fd.read() doesn't return any data after the first call is that you're already at EOF; you need to reset the file position with fd.seek(0) to read more data (however: for /proc, I would recommend closing the file and reopening it).

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