[Zope3-dev] PyCon DC 2003: Call For Papers

[Shane Hathaway]

Stephan Richter wrote:
> On Thursday 05 December 2002 08:41, Guido van Rossum wrote:
> 
>>- Module and package names should be short and lowercase.  Motivation:
>>  you'll never again confuse a class with its module.
> 
> 
> I like that.
> 
> 
>>- Modules should contain more than one class (a rule designed to be
>>  broken :-).  Motivation: this way the presentation order of classes
>>  (whether top-down or bottom-up) can help the reader to understand
>>  what's important; and it clarifies what classes (or functions) are
>>  related.  Compare to trying to find where to start in a directory
>>  full of classes, listed alphabetically.
> 
> 
> That has another advantage: You do not have to write the name twice in the 
> import. Right now we often have: from package.ClassName import ClassName

I've been trying out a complementary convention in AdaptableStorage: all 
public classes are available through a special module called "public". 
For example, if I made a class JobBoard and put it in jobboard.py, 
located in the package "jobboard", I'd put a public.py next to it that 
includes the line "from jobboard import JobBoard".  Other packages would 
use this class with the statement "from jobboard.public import 
JobBoard".  There are many advantages:

- The public.py module becomes the documentation for use of the package 
by other packages.

- The class name does not get repeated when other packages use the class.

- You can convert any package to this convention just by adding a 
"public" module.  It conflicts with no other conventions (unless 
"public" ever becomes a Python keyword ;-) )

- It's a lot like Java imports, but without the warts.  Hence I think it 
is likely to help those coming from Java, as I did.  In Java you would say:

import jobboard.JobBoard;

In Python you would say:

from jobboard.public import JobBoard

... which are essentially equivalent and easy to translate.  But what if 
you want to import a lot of classes from another Package?  Java:

import jobboard.JobBoard;
import jobboard.HTMLJobBoardRenderer;
import jobboard.XMLRPCJobBoardRenderer;

In Python you can shorten this to:

from jobboard.public import JobBoard, HTMLJobBoardRenderer,\
     XMLRPCJobBoardRenderer

- As just illustrated, you can more easily import multiple classes from 
a package.  You don't need multiple "import jobboard.xxx" statements.

- Other packages can still choose to ignore the convention and get the 
classes directly.

Shane