🌐 Mailman 3 July 2003 - Python-list - python.org

Undeliverable: Re: Application
by System Administrator July 1, 2003

July 1, 2003

Your message To: bhyde(a)gensym.com Subject: Re: Application Sent: Tue, 1 Jul 2003 20:38:31 -0400 did not reach the following recipient(s): bhyde(a)gensym.com on Tue, 1 Jul 2003 18:39:06 -0400 The recipient name is not recognized The MTS-ID of the original message is: c=US;a= ;p=Gensym;l=HQMAIL0307012238N4PJN1NK MSEXCH:IMS:Gensym:HQSITE:HQMAIL 0 (000C05A6) Unknown Recipient

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Re: Newbie: Tkinter and macPython
by gtewalt＠earthlink.net July 1, 2003

July 1, 2003

"Russell E. Owen" <no(a)spam.invalid> wrote in message news:<bdq5nv$2bdo$1(a)nntp6.u.washington.edu>... > In article <f9b7c11d.0306281825.5cf24367(a)posting.google.com>, > gtewalt(a)earthlink.net (gt) wrote: > > >I'm waffling between Ruby, and Python as a programming > >language. > >I borrowed a friends book on Ruby, and have played with > >it a bit. > >I went by the library to check out 'Learning Python' > >but i was too late, the library had closed already... > > > >Anyway, to the point. > >I downloaded macPython for OSX, and was trying to get > >a simpe Tkinter example to work form Lundh's tutorial, > >I think it was. > >Bu I get an error... > > > ># File: hello1.py > > You have hit MacPython at a slightly awkward time. MacPython (through > version 2.2.x) runs as a carbon application on MacOS X and the Tk > interface was never "carbonized" (I think because the underlying Tk was > never carbonized, but whatever the reason, the fact is it will not > work). (MacPython can also be configured as a classic app, simply by > double clicking the suitable application in the installation, in which > case Tkinter runs just fine at least if you boot into MacOS 9, I'm not > sure if it runs in Classic emulation mode.) > > If you want to run Python 2.2.x/Tkinter on MacOS X you can do it as > follows: > > Download and install aqua tcl/tk. Version 8.4.1 is the latest that will > work with Python 2.2.x. A binary distribution is available from > <http://www.maths.mq.edu.au/~steffen/tcltk/TclTkAqua/>; there are three > flavors available; I recommend TclTkAqua (having "wish" around is nice. > I'm not sure the full "BI" version adds anything you'll find useful. > > Download and install Python. For Python 2.2.x I suggest using Bob > Ippolito's binary installer <http://redivi.com/~bob/>, since it includes > Tkinter and some other useful stuff already built. Note that it also > includes wxPython, an alternate GUI that you may wish to look at. > > If you prefer to install thiss stuff from source, my home page > <http://www.astro.washington.edu/owen/> has a suitable link. Installing > from source is not for the faint of heart (though it'll be easier for > Python 2.3). > > Warning: unix Python 2.2.2 requires \n line endings for files, which is > not the Mac norm. Any decent text editor (e.g. BBEdit or Pepper) *can* > save files with \n, but you have to configure it to do it. This problem > will go away with Python 2.3. > > > Python 2.3 will be the first version that unifies "MacPython" and unix > Python (thanks to hard work by Jack Jansen and others). Python 2.3b1 is > available now from Jack's MacPython site > <http://homepages.cwi.nl/~jack/macpython.html>. Install aqua Tk/tcl as > above, then install the 2.3b1 binary installer. You have to do a bit > more work to get Tkinter installed -- I think MacPython 2.3b1 comes with > a package manager that will do the job, but I've not yet tried it. > > I personally use both 2.3b1 and have had no problems with it. (I > actually have a dual installation; 2.3b1 with aqua Tk and 2.2.2 with > unix style x-windowing Tk; both work well.) > > In conclusion, life will be grand when Python 2.3 is released. Meanwhile > it's a bit of work, but not too bad. > > > I hope this helps. > > -- Russell Wow. I never expected anything this thourough for a response. Thanks Russell. I have actually installed MacPython 2.3b1. I tried the package manager, but at the time it wouldnt connect to the 'database' (if I remember correctly) At any rate, it looks like I need aqua Tk. It would seem that I should un-install 2.3b1, install aqua Tk, then reinstall 2.3b1 and implement the package manager. Thanks again. -- Greg

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exchange.HrFindExchangeGlobalAddressList
by c42 July 1, 2003

July 1, 2003

Can anyone explain how to use exchange.HrFindExchangeGlobalAddressList, perhaps give an example? Thanks! c42

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RE: Identity inconsistency and unification of types and classes
by Michael Chermside July 1, 2003

July 1, 2003

Rim writes: > With the great unification of types and classes, what will happen to the > following identity inconsistency? > > >>> class myint(int): pass > ... > >>> a=int(1); b=int(1) > >>> a is b > 1 > >>> a=myint(1); b=myint(1) > >>> a is b > 0 In all likelihood it will remain as it is. The current behavior is NOT what you think it is. For instance: ActivePython 2.2.1 Build 222 (ActiveState Corp.) based on Python 2.2.1 (#34, Apr 15 2002, 09:51:39) [MSC 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> a = int(32000) >>> b = int(32000) >>> a is b 0 The *actual* rule is this: if two objects x and y are not immutable, then "x is y" will be false. Normally, you would want to use "x == y" instead, to see if two objects were equal, but if what you REALLY want to know is whether they will CONTINUE to be equal if one gets changed, then that's what "is" is used for. (Plus occasionally for performance reasons, and in the idiom "x is None", which isn't really any different from "x == None" except if you redefine None, which you shouldn't do.) For IMMUTABLE objects, there's no reason to EVER need "x is y"... since you can't change either one, "x == y" will tell you whatever you need to know. Thus Python is allowed to have "x is y" return either true OR false, as an optimization. Programmers shouldn't rely on the result (except, as always, if you really know what you're doing). Right now, Python allows "is" to return true between strings that are very short and strings that appear in the source code, but sometimes not between strings that are constructed at runtime. For integers, "is" will return true between numbers in the range [-1..99], and may return false for numbers outside that range. Both of these rules are specific optimizations and may change without warning. What you CAN assume is that if you create a mutable subclass of int (why would you do such a thing?), that "is" will return false on different instances. If your subclass is immutable, you can't assume anything. -- Michael Chermside

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RE: Suggesting for overloading the assign operator
by sismex01＠hebmex.com July 1, 2003

July 1, 2003

> From: rimbalaya(a)yahoo.com [mailto:rimbalaya@yahoo.com] > Sent: Martes, 01 de Julio de 2003 12:07 p.m. > > Well, what about the idea of providing another statement, the one I > proposed in the original post? > > '=' statement assigns type and value > ':=' statement assigns value only > > Rim > Probably the reason most prople on this list don't quite like these threads is that there's no *need* for this "value-assignment" operation. For one, how would you implement it for immutable data types? This ":=" statement you're talking about already exists for lists, you can do something like: A[:] = some_other_list Why? Because you're assigning to a slice of A (which happens to be the whole list) the contents of the second list. But, what about strings, for example? Or ints? Or longs, floats, complexes? These data types are not mutable, an int object like, for example, 123, cannot change it's value to some other value, like 124. It's created with that value and lives like that until destroyed, or the end of the program. Same goes for all those other immutable types mentioned above. Why would you need such an operation? Is there some unsurmountable programming problem that cannot be solved except by such a vile hack as an overloadable assignment operator? The existance of huge software projects already done in python (such as Zone, Yahoo, and others) tells me that the language really doesn't need it. Another question would be, why not tell us what you're trying to do (which most probably looks like a C++ algorith or something like that) and how can we help you turn it into a Python algorithm? Programming C++ in Python is difficult. -gustavo Advertencia:La informacion contenida en este mensaje es confidencial y restringida, por lo tanto esta destinada unicamente para el uso de la persona arriba indicada, se le notifica que esta prohibida la difusion de este mensaje. Si ha recibido este mensaje por error, o si hay problemas en la transmision, favor de comunicarse con el remitente. Gracias.

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placing text at point on console
by bart July 1, 2003

July 1, 2003

I'm trying to place text at a certain point on the console. But I can't figure out any way to do this. For instance place a '@' at point 6,8. Any hints? (I'm trying to display a 'map'. Think nethack) Thanks, Bart

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Why does it work ?
by Michel Combe July 1, 2003

July 1, 2003

I'm trying to send a mail with an attached file. I use the following code and *it works* but I don't understand why and I hate that. for filename in os.listdir(dir): path = os.path.join(dir, filename) if not os.path.isfile(path): continue ctype, encoding = mimetypes.guess_type(path) if ctype is None or encoding is not None: ctype = 'application/octet-stream' maintype, subtype = ctype.split('/', 1) if maintype == 'text': fp = open(path) msg = MIMEText(fp.read(), _subtype=subtype) fp.close() msg.add_header('Content-Disposition', 'attachment', filename=filename) outer.attach(msg) In the "dir" directory, I have 2 text files : - "texte.txt" which is the text I want inside the body of the message and - "fichier.txt" which is the file I want attached. Why is "texte.txt" the only file that I find in the body of the message. Both files are text, so the MIMEText instruction shoud be executed for both files, No ? Also add_header should be executed for both files resulting in 2 attached files ? Which instruction says what is included in the body and what is attached to the mail ? I must say I'm not sure of what MIMEText and add_header exactly do. I read the doc but it was not too clear for me. Thanks for your help Michel Combe

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Haskell distutils-type system
by Isaac Jones July 1, 2003

July 1, 2003

Hello Python Community. I bring greetings from the Haskell community (http://www.haskell.org) ;) There has been a lot of discussion of late about creating a grand-unified build & distribution system for "3rd party" Haskell libraries (those not distributed with the compilers). Python's Distutils has come up a few times. The Haskell Library Infrastructure Project's web page is just a wiki page which can be found here: http://www.haskell.org/hawiki/LibraryInfrastructure. I'm running this project. I also wear another hat in that I'm interested in maintaining Debian packages related to Haskell, so I want to make my job easier by 1) writing software support, and 2) making it easy for other people to maintain Debian packages so I don't have to :) I've read much of the documentation at http://www.python.org/sigs/distutils-sig/doc/. I've also made a toy Python program that uses distutils. It occurs to me that the issues that were facing the Python community are strikingly similar to those facing the Haskell community now, except perhaps for the fact that there are at least 3 very strong Haskell "compilers" that we want to support. One idea for this distribution system, which we're calling the Library Infrastructure Project, is to create a nice gmake-based build system, document it, and leave it at that. Another idea is to use a Haskell-based Distutils type system. Now I think that the Haskell-based system should work out-of-the-box for pure-haskell modules (no extensions), and maybe wrap a more complex make-based system where necessary (as when interfacing with C or using preprocessors). I definitely want to optimize for the common case of joe-haskell-programmer wanting a nice way to distribute modules to his friends, but of course I also want to allow Haskell developers to do more complex things. The main issues facing us are: 1) there are a variety of Haskell "compiler" implementations, one of which is an interpreter :) 2) not all Haskell implementations are available on all architectures (ghc for instance) 3) just about every Haskell "compiler" and release is binary-incompatible, (except maybe for nhc98). That is, if we were going to distribute binary libraries, we'd need different binaries for ghc4, ghc5, and ghc6. Also we'd need different binaries for profiling versions of the libraries, etc. For instance, if I were to create a binary package HUnit, which is a simple case since its pure Haskell code, I would need: hunit-{hugs,nhc98} hunit-ghc{4,5,6} hunit-ghc{4,5,6}-prof And whenever a new version of GHC6 is released (for instance), all of the packages like hunit-ghc6 would need to be updated at the same time. That doesn't even get into the issues of the wide variety of preprocessors that are common in this rapidly advancing language[1]. So all of this suggests to me that we want to keep a global list of installed libraries and recompile them whenever a new Haskell "compiler" gets installed. This is why I want an abstraction layer above make. So I want to ask you if you can think of any obvious things we should watch out for if we try to do something similar to what Python is doing. Also, there was some mention (in the related "summary of the Developer's Day session") of Python's distutils creating a Makefile and wrapping calls to make, is this what you're doing? Do you / did you find yourself duplicating a lot of what make already does, ie dependencies, etc, or do you utilize make? What about configuration, do you typically interface with autoconf somehow, or does distutils have its own way to figure out configuration details? Is a typical distutils setup.py program pretty much like what we see in the example documentation? The developer provides some meta-data and gets a distribution tool? Is there any support for more complex stuff like interfacing with external systems? Does distutils handle dependencies? I've hacked together something that creates a source tarball and a basic Debian package from a Haskell version of the distutils-type metadata. I can make that available in a few days if anyone is interested. peace, isaac [1] Haskell is designed to have a "stable" version, Haskell98, and the compilers come with a variety of extensions so that it is very useful as a research language as well.

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how to register private python codecs?
by garabik-news-2002-02＠kassiopeia.juls.savba.sk July 1, 2003

July 1, 2003

I am developing and application that makesheavy use of (my own) codecs not distributed with python (i.e. unicode(text, 'kamenicky')) I put the codec into file kamenicky.py, placed the file into /usr/lib/python/encodings, but now I want to distribute my application, and I assume that users won't always have the possibility of copying files into /usr/lib/python/encodings. Is there a (simple) way how to register this encoding so that the file "kamenicky.py" can be in (let's say) current directory? TIA -- ----------------------------------------------------------- | Radovan Garabík http://melkor.dnp.fmph.uniba.sk/~garabik/ | | __..--^^^--..__ garabik @ kassiopeia.juls.savba.sk | ----------------------------------------------------------- Antivirus alert: file .signature infected by signature virus. Hi! I'm a signature virus! Copy me into your signature file to help me spread!

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RE: Suggesting for overloading the assign operator
by Michael Chermside July 1, 2003

July 1, 2003

Rim writes: > I have been thinking about how to overload the assign operation '='. [...] > the > second assignment below ereases all Currency knowledge from variable > 'c', when the user only wanted to update the value of c, not its type: > > c=Currency(5) > c=7 > > I fully understand the workaround of doing c=Curreny(7) instead, but > users don't want to be bothered with that. I think you have a fundamental misunderstanding of how assignment works in Python. In some languages (C for example) variables are things that have a TYPE and a VALUE. You typically set the TYPE by declaring the variable and typically can't change it. You typically set the VALUE by assignment. In at least one case (C++ is the only example I know of) you can override the meaning of assignment to variables of a certain type. In Python, variables do NOT have a type and a value. Instead, variables have a single value, which is always some object. Objects have a type (and sometimes a class also... I'm not going to worry about this difference). But there's little connection between variables and types. When we assign (actually, a better term is "rebind") a variable it can be assigned to any object. >>> x = "a string" >>> x = 5 >>> x = Currency(7) I'm confident that what you want to achieve can be accomplished in Python, you just have to adjust your mindset. In Python it's useful to think of things in terms of namespaces. (See last line of "http://www.awaretek.com/zen.html".) Namespaces are just dictionaries -- and they're used throughout Python. When you write >>> x = "abc" you are simply performing __setitem__("x", "abc") on a namespace called the "module globals". If you want, you can get ahold of this dictionary via the function globals(), and you can see that manipulating it is just the same as using "=". >>> x = 'a string' >>> theGlobals = globals() >>> print theGlobals {'__builtins__': <module '__builtin__' (built-in), '__name__': '__main__', 'theGlobals': {...}, '__doc__': None, 'x': 'a stri ng'} >>> theGlobals["y"] = 7 >>> print y 7 Function definition is just another operation on this namespace... writing "def func(x): return x + 1" is (almost) the same as "globals()["x"] = lambda x: x + 1". When you use local variables within a function, you are manipulating another namespace, (for performance purposes it's not actually implemented as a dictionary, but it acts as if it were... just call locals() to see it as a dict). So when you say that you want your users to be able to do this: >>> x = Currency(5) >>> x = 7 and then have x be a Currency object, what you're *really* saying is that you want to take over control of the namespace that your users are working in so that they can't store just anything in it, but are forced to store only Currency objects. Or perhaps you mean for them to be able to store only Currency objects for any key which was previously used for a Currency object. Or maybe you mean that if they try storing a NUMBER in a slot which was previously used to store a Currency object that a new Currency object should be stored instead. Actually, I'm not quite certain what your requirements are, but it's pretty clear to me that what you want is a special namespace with custom behavior. Well, Python provides special namespaces with customizable behavior. They're called classes. Classes are just another namespace ("one honking great idea")... well, technically TWO namespaces: one for the class itself and one for the individual object. Normally, saying "myObject.x = 7" performs another dictionary assignment (this dictionary is accessible as "myobject.__dict__"), but you can use the special functions __getattr__, __setattr__, __delattr_, and perhaps __getattribute__ to customize its behavior. So I'm guessing that you can accomplish your objective by getting your users to store their values as fields in an object and providing customized behavior on that object. I was going to suggest that you create a custom dict type (here's one that just prints stuff out when modified... you could use any logic you wanted): >>> class NoisyDict(dict): ... def __setitem__(self, key, value): ... print 'setting %s to %r' % (key, value) ... dict.__setitem__(self, key, value) ... and that you then use it in an exec statement, like this: >>> exec "x = 7\nprint x" in NoisyDict() 7 Unfortunately, it didn't work (that printed "7", but didn't print "setting x to 7"), so you may need a slightly better guru than me to get this working. Or if you can better describe your PARTICULAR problem, I may be able to figure out how to approach it. But I'm almost certain that there's a much easier way than changing how Python does assignments. -- Michael Chermside

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