[Python-ideas] parameter omit

[Aaron Brady]

> -----Original Message-----
> From: python-ideas-bounces at python.org [mailto:python-ideas-
> bounces at python.org] On Behalf Of Aaron Brady
> Sent: Friday, May 11, 2007 12:23 AM
> 
> > -----Original Message-----
> > From: Steven Bethard [mailto:steven.bethard at gmail.com]
> > Sent: Friday, May 11, 2007 12:13 AM
> >
> > On 5/10/07, Aaron Brady <castironpi at comcast.net> wrote:
> > [snip]
> > > The new way:
> > >
> > > my_b, my_c= paramdefault, paramdefault
> > > [code to assign my_b and my_c]
> > > foo(a, my_b, my_c)
> >
> > As another poster mentioned, the normal way to write this is::
> >
> >     kwargs = {}
> >     if use_default_b:
> >         kwargs['b'] = my_b
> >     if use_default_c:
> >         kwargs['c'] = my_c
> >     foo(a, **kwargs)
> >
> > It is so extremely uncommon to need to do such a thing that I'm firmly
> > against adding any additional syntax. Syntax should only be introduced
> > for common things that many people need.
> >
> > STeVe

Steve,

Take a shot at this one.

class WebRetrieveElement:
	def netretrieveOld( self ):
		if hasattr( self,'hook' ) and self.filename:
			urlretrieve( self.url, self.filename, self.hook )
		elif hashook:
			urlretrieve( self.url, reporthook= self.hook )
		else:
			urlretrieve( self.url, self.filename )

	def netretrieveNew( self ):
		filename= self.filename or ParamDefault
		hook= hasattr( self,'hook' ) and self.hook or ParamDefault
		urlretrieve( self.url, filename, hook )

What is the default parameter for the function?  Problem is, the docs don't
say what it is.  Does it pick its own filename to use for empty inputs?