Design Pattern and Python: Any book recommendation? Your view?

[Roy Smith]

In article 
<6097694.446.1320366784098.JavaMail.geo-discussion-forums at prap37>,
 Anthony Kong <anthony.hw.kong at gmail.com> wrote:

> Sorry to resurrect this topic. By google search the last discussion was in 
> 2003.

What?  We're bring it up again, SO SOON!?


> I would like to find out what is the current prevailing view or consensus (if 
> any) on the use of Design Pattern in python?
> [...]
> I myself pretty much subscribe to the view that the nature of python language 
> actually do away much of the need of the use of DP

To a certain extent, I agree.  I don't have a huge amount of experience 
in Design Patterns, but have read (years ago) the obligatory Gang Of 
Four book.  My impression was that much of that book was about how to 
build sane data structures to do useful things given the uber-bondage 
constraints of the C++ and Java typing systems.

For example, let's look at Singleton.  It's a useful pattern.  Here's 
how I would implement Singleton in Python (hand-waving a bit about the 
syntax details):

class Printer:
   thePrinter = None

   @staticmethod
   def get():
      if Printer.thePrinter is None:
         Printer.thePrinter = Printer()
      return thePrinter

   def print(self):
      "print some stuff"
      whatever


That seems to cover everything Singleton needs to do.  In your 
application code, you do:

myPrinter = Printer.get()
myPrinter.print(....)

and you can sleep easy knowing you've got the same Printer instance 
every time.  The GoF version for C++ is filled with minutia about 
private constructors and assignment operators.  All that stuff is 
important to get right in C++, but it has nothing to do with Singleton, 
per se.  It's just all the gunk you have to worry about to correctly 
implement Singleton in C++.