Thoughts about Python

Paul Prescod paul at prescod.net
Wed Feb 25 03:33:04 CET 2004


Greg Ewing (using news.cis.dfn.de) wrote:

>....
> You're right that naming conventions (or lack thereof) in Python
> leave something to be desired, but we're stuck with many of them
> for historical reasons. 

Not really. If "open" can be renamed "file" it could also have been 
renamed File. To be honest I think that the real problem is that Guido 
is allergic to caps. I don't know how None snuck in. ;)

> Your suggested convention (classes start with uppercase, functions
> with lowercase) has its uses, and I tend to follow it in most of
> the code that I write, but it has its drawbacks as well. A
> counterargument often put forward is that users of a class usually
> don't care whether something is really a class or whether it's
> a factory function, and often you would like to be free to change
> the implementation from one to the other without affecting client
> code. With a naming convention that distinguishes classes from
> functions, you can't do that.

Changing from a function to a class is _always_ easy.

def open(filename, flags):
	return File(filename, flags)

The trickier issue is having the class itself export the interface the 
client code is used to.

Changing from a class to a function is never really very safe:

class myobject(File):
	...

if isinstance(myobject, File):
	....

How can you change File to be just a function safely? But anyhow, why 
would you want to?

  Paul Prescod






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