[Python-ideas] Simple class initialization

[Ethan Furman]

dag.odenhall at gmail.com wrote:
> On 16 April 2011 13:50, Adam Matan <adam at matan.name> wrote:
>> 0. Abstract
>> ===========
>> A class initialization often begins with a long list of explicit variable
>> declaration statements at the __init__() method. This repetitively copies
>> arguments into local data attributes.
>> This article suggests some semi-automatic techniques to shorten and clarify
>> this code section. Comments and responses are highly appreciated.

[snippers]

> class Process:
> 
>     # Defaults and documentation as class attributes
>     pid = None
> 
>     def __init__(self, **kwargs):
>         for k, v in kwargs.iteritems():
>             setattr(self, k, v)

I like the initialiser function myself:

8<-------------------------------------------------------------
def acquire(obj, kwargs):
     Missing = object()
     for kw, val in kwargs.items():
         name = '_'+kw
         attr = getattr(obj, name, Missing)
         if attr is Missing:
             name = kw
             attr = getattr(obj, name, Missing)
         if attr is not Missing:
             setattr(obj, name, val)

class Process:
     pid = None
     ppid = None
     cmd = None
     reachable = None
     user = None
     _fd = None
     def __init__(self, pid, ppid, cmd, fd, reachable, user):
         acquire(self, locals())
         print(self.pid)
         print(self.ppid)
         print(self.cmd)
         print(self.reachable)
         print(self.user)
         print(self._fd)

if __name__ == '__main__':
     p = Process(9, 101, 'cd /', 0, 'yes', 'root')
8<-------------------------------------------------------------

Don't think it needs to be in the stdlib, though.

~Ethan~