Re: Calling private base methods
> The fact that I had > to resort to this trick is a big indication of course that genuinely > private members (as opposed to a 'keep off' naming convention) are a bad > idea in general. The fact that you had to resort to this trick is a big indication that the library you were using is bad designed; it has nothing to do with private members being a bad idea. You were using a library which interface was in-complete (provided that you "genuinely" really needed to access the private member to do what you wanted to do). Private members is a great thing. They are the foundations of encapsulation and object oriented design. The fact that Python allows you to access "private" methods because the only "restriction" is the name mangling does not mean you should access them and use them directly. I don't see the way private members are handled in Python a strenght or a weakness of the language as compared to other languages. However, I do see libraries that do not provide all the needed interface methods as poor designed, or programmers that try to work around the public interface of a class when it is not needed as poor programmers. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling private base methods
> > C++'s and Java's approaches are vitiated by an unspoken assumption that > the library's designer is some kind of demigod, while the writer of code > that uses the library is presumably still struggling with the challenge > of opposable thumbs. That might be your point of view. To me, the library designer is the one that has done the homework and should know better how to simplify things for others not a God. No one uses a high level library if implementing the low-level your self is easier. Libraries provide functionality that allow the application programmer to concentrate in what he is being paid for, making the application. An application programmer will have to define what the correct interface for the application is (for example, what UI to provide). There will be users that will say, I wish this application had a way of doing this, but unless they were technically savy and wanted to spend the necessary time to understand how the application works, they would not write the feature themselves; they will request that feature to the programmer. > In real life, the skills of the two people in > question are likely to be much closer, and since designing libraries for > use in all kinds of applications is a really hard task, it's likelier > than the library designer will make an error in designing his or her > library, rather than the application programmer in using that library. Those are called defects or "bugs". When I find a bug in a library or an application, I submit a bug report. I might have to work around it for a little bit, but I don't just work around it and call it goods. Library designers are normal programmers that work under a set of requirements like any other programmer (application programmers included), but when I find a bug in an application, I report it and try to work around it until it gets fixed; I don't hack the application or re-write my own just because a found a bug. > > Purely-advisory encapsulation approaches, like Python's, even the odds. > Actually, I'd argue that even double-leading-underscores are overkill > more often than not (and single-leading-underscores the compromise that > is generally prefereable). You see it as an intelligence challenge, where I see it as making things easier for everybody. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: What makes an iterator an iterator?
> > class Parrot(object): > def __iter__(self): > return self > def __init__(self): Typo right here > self.next = self._next() write: self.next = self._next no parenthesis. > def _next(self): > for word in "Norwegian Blue's have beautiful plumage!".split(): > yield word > See previous explanation. thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: What makes an iterator an iterator?
Sorry, my previous post was incomplete. I didn't realized that you implemented _next() as a generator funcition. Besides changing __init__() from self.next = self._next() to self.next = self._next you need to implement __iter__() as: return self.next() > class Parrot(object): > def __iter__(self): > return self > def __init__(self): > self.next = self._next() > def _next(self): > for word in "Norwegian Blue's have beautiful plumage!".split(): > yield word > -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling private base methods
> After all, that's what duck-typing is about. There is no official > interface declaration, just an implicit protocol. And "private" methods > or members are part of that protocol as well. I don't think so. Duck-typing is about implementing the expected public interface, and has nothing to do with accessing private members of a class, nor overriding those members. - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling private base methods
> You appear to have led a very sheltered life if the only libraries you ever > use are ones where you can always get a change to the library api in a > timely manner. > The thing here is that we are not talking about my life. I may not have expressed my self correctly, but you are not understanding the point I am trying to make. You can say that you don't like C++ or Java because they put too much restriction when members are declared private. That you prefer Python's approach because in a time of need it will make your life easier. All that is fine with me. It is just a matter of taste. But the truth is that C++ and Java made a decision to do that for a reason, and the times when you have to work around those language features come once in a blue moon; they are the exception, not the rule, and you don't implement features in a language, or for that matter in an application, to simplify the exceptions; you try to implement the most common scenarios. Which features you add to your programs? The features your customers' ask for because they need them and they use them all the time or the ones that you like to implement even if they are not ever used? Thanks, - Isaac -- http://mail.python.org/mailman/listinfo/python-list
Re: My Python annoyances
> Hmm, on my PyCon mug there are words "Python: so easy...even your BOSS > can use it!" Oh man! I would've killed for a mug like that a year ago. I was working for this guy, who had the entire build process automated in .BAT scripts. We spent more time fixing the build process than devoloping our product. Anyway, I started to move the entire thing to Python. Using a real programming language, allows creating a more robust process. It also allows separating data and code, which comes very handy when the data changes to not have to touch the code. So a year ago, I moved to another department. I would not get into the details of why, but I am just going to say that I'm much happier now. One day, I walking down the hall, and I see a book in my old boss' desk: "Learning Perl." I thought to my self, "You gotta be kiddin". So I saw him in the coffee area, and I asked him about it. His answer was, "Yeah, I'm re-writing the build scripts in Perl because you are the only one that knew Python, and we need to maintain them." Well, there is no-one in that team that knows Perl either, and if they haven't been able to learn Python in the couple of years I tried to push it, I really doubt they are going to learn Perl. Or maybe, the problem was that I was trying to push Python, so they are doing this just to prove me wrong. Like I said, I'm much happier now, and so much glad to be out of that team. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to find the present working directory using python.
> how to find out the present working directory using python. > Try this: import os os.getcwd() It returns the current working directory. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Experiences with Py2Exe
Hi, I am looking for feedback from people that has used or still uses Py2Exe. I love to program in python, and I would like to use it to write support tools for our development team, but I cannot require everyone to install python in their machines, so I was thinking that Py2Exe would help on that. The support tools I write are mostly command line driven (no GUI), but in the future, I would like to write some expert applications that will contain GUI. I was thinking on using wxPython for the GUI, so I was wondering how well behaves Py2Exe with the wxPython module. Other modules I use besides the standard modules are CTypes and the Perforce python module p4.py. I try not to use any of the win32 stuff, but I can see how I will have to for some utilitites, so if anyone has experience with the win32 modules and Py2Exe, any feedback will be highly appreciated. Thanks, Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: Experiences with Py2Exe
> > I did a project with wxPython and py2exe. Just great :-) I also used > Inno Setup (http://www.jrsoftware.org/isinfo.php) to create an > installer. You should be able to learn/use both in one day. > Do you have a specific reason for using Inno Setup and not a Windows Installer based setup? Will Inno Setup play especially well with py3exe or was it just the learning curve of using a Windows Installer setup? I am asking this because I have a lot of experience using the Windows Installer service, and I also have all the productivity tools available to create an installer for my tools if I needed to, but now I am curious about this Inno Setup. Thanks, Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: One module per class, bad idea?
> Yes, it would be a bad idea. =) Saying it is a bad idea and not explaining why will not help anyone. I would like you to elaborate on why it is a bad idea to have one file per class. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Re: One module per class, bad idea?
> make the import statements look good. You can still make your import statements look good and have one class per file, that's one of the __init__.py wonderful features. Also, C++ support stand alone functions and the rule is to organize classes and their interface (functions that operate in objects of the class are considered part of the interface) in their own module. I will like to understand why this will not be a good idea for python, other than to make beautiful import statements that is. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
Are all classes new-style classes in 2.4+?
Hi, This is probably a very basic question, but I've been playing with new style classes, and I cannot see any difference in behavior when a declare a class as: class NewStyleClass(object): or class NewStyleClass: I declare property members in both and it seems to work the exact same way. I am using Python 2.4, and I was wondering if by default, all classes are assumed to be derived from "object". If not, can someone point me to some place where I can learn more about new-style classes and their advantages? All the documentation I've found is very vague. Thanks, - Isaac. -- http://mail.python.org/mailman/listinfo/python-list
CAB files manipulation API (again).
Hi, I am sorry to post this question again, but when I did it the other day, my news reader got stucked downloading new messages, and it has been that way for a few days. It still gets stucked if I try to download old messages. Anyway, does anyone know of a Python module, API, etc. that allows to manipulate CAB files? Thanks, -- Isaac Rodriguez SWE Autodesk. There are 10 types of people. Those who undertand binary, and those who don't -- http://mail.python.org/mailman/listinfo/python-list
Coding Standards (and Best Practices)
Hi, I am fairily new to Python, but I am really liking what I am seeing. My team is going to re-design some automation projects, and we were going to use Python as our programming language. One of the things we would like to do, since we are all new to the language, is to define a set of guidelines and best practices as our coding standards. Does anyone know where I can get some information about what the community is doing? Are there any well defined guidelines established? Thanks, -- Isaac Rodriguez SWE Autodesk. There are 10 types of people. Those who undertand binary, and those who don't -- http://mail.python.org/mailman/listinfo/python-list
Documenting Python code.
Hi, Are there any standarized ways of documenting Python code? When I check the __doc__ attribute of the standard modules, the results are kind of plain. Is everyone using this style? Since Python is a very powerful language parsing strings, replacing expressions, and processing XML, I was wondering if people documents the code using constructs similar to JavaDoc and then use some functions to display the documentation with a little bit more of structure. Python is a dynamically typed language, which makes me think of the importance of documenting not only the purpose of a particular function or class method, but also what requirements should be met by the objects passed as parameters, what will the function return, and what type of erros can happen. I don't see any of this information in the __doc__ attributes, so I was wondering if people is using some other way to document their code. If there is no standard way to do this inside the Python community, does anyone feels there is a need for standarizing it? Thanks, -- Isaac Rodriguez SWE Autodesk. There are 10 types of people. Those who undertand binary, and those who don't -- http://mail.python.org/mailman/listinfo/python-list
Python API to manipulate CAB files.
Does anyone know of a Python API to manipulate CAB files? Thanks, -- Isaac Rodriguez SWE Autodesk. There are 10 types of people. Those who undertand binary, and those who don't -- http://mail.python.org/mailman/listinfo/python-list
