Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #17876

Re: Early and late binding [was Re: what does 'a=b=c=[]' do]

Show key headers only | View raw

On 12/24/2011 07:25 PM, Steven D'Aprano wrote:
>> I'd use a function attribute.
>>
>> def func(x, y=None):
>>    if y is None:
>>      y = func.default_y
>>    ...
>> func.default_y = []
>>
>> That's awkward only if you believe function attributes are awkward.
>
> I do. All you've done is move the default from *before* the function is
> defined to *after* the function is defined, instead of keeping it in the
> function definition. It's still separate, and if the function is renamed
> your code stops working. In other words, it violates encapsulation of the
> function.

Although we can solve that (default being after the function is defined) 
using a simple decorator:

def funcargs(**args):
     def __decorate_with_args(func):
         for k,v in args.items():
             setattr(func, k, v)
         return func
     return __decorate_with_args

Usage:

@funcargs(foo=4)
def bar(baz):
     return baz + bar.foo

et voila, we had just reinvented early binding default argument, with a 
much uglier syntax.

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

what does 'a=b=c=[]' do Eric <einazaki668@yahoo.com> - 2011-12-21 14:25 -0800
  Re: what does 'a=b=c=[]' do Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2011-12-21 18:20 -0500
    Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-21 23:48 +0000
      Re: what does 'a=b=c=[]' do Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-24 19:41 +0100
        Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-25 13:16 +0000
    Re: what does 'a=b=c=[]' do Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-24 19:45 +0100
  Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-21 23:44 +0000
    Re: what does 'a=b=c=[]' do Eric <einazaki668@yahoo.com> - 2011-12-22 20:27 -0800
  Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-21 16:50 -0800
    Re: what does 'a=b=c=[]' do Rolf Camps <rolf@roce.be> - 2011-12-22 09:51 +0100
      Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-22 18:10 -0800
        Re: what does 'a=b=c=[]' do Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-22 19:59 -0700
          Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-22 19:40 -0800
            Re: what does 'a=b=c=[]' do Chris Angelico <rosuav@gmail.com> - 2011-12-23 15:25 +1100
            Re: what does 'a=b=c=[]' do Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-22 22:22 -0700
              Re: what does 'a=b=c=[]' do alex23 <wuwei23@gmail.com> - 2011-12-22 22:00 -0800
        Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 00:38 -0800
          Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 09:39 +0000
            Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 02:22 -0800
              Re: what does 'a=b=c=[]' do Robert Kern <robert.kern@gmail.com> - 2011-12-23 13:10 +0000
                Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 05:23 -0800
                Re: what does 'a=b=c=[]' do Robert Kern <robert.kern@gmail.com> - 2011-12-23 13:53 +0000
                Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 06:57 -0800
                Re: what does 'a=b=c=[]' do Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 15:33 +0000
                Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 07:59 -0800
          Re: what does 'a=b=c=[]' do Ethan Furman <ethan@stoneleaf.us> - 2011-12-23 00:49 -0800
          Re: what does 'a=b=c=[]' do Chris Angelico <rosuav@gmail.com> - 2011-12-23 20:59 +1100
            Re: what does 'a=b=c=[]' do rusi <rustompmody@gmail.com> - 2011-12-23 02:31 -0800
              Timeout when calling COM objects on Windows Wong Wah Meng-R32813 <r32813@freescale.com> - 2011-12-23 11:20 +0000
              Re: what does 'a=b=c=[]' do Michael Torrie <torriem@gmail.com> - 2011-12-23 10:23 -0700
            Re: what does 'a=b=c=[]' do Neil Cerutti <neilc@norwich.edu> - 2011-12-23 13:10 +0000
              Re: what does 'a=b=c=[]' do Neil Cerutti <neilc@norwich.edu> - 2011-12-23 13:13 +0000
                Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 15:49 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Chris Angelico <rosuav@gmail.com> - 2011-12-24 02:55 +1100
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-23 22:32 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Chris Angelico <rosuav@gmail.com> - 2011-12-24 09:50 +1100
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-24 08:11 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Roy Smith <roy@panix.com> - 2011-12-23 11:15 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 05:43 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Mel Wilson <mwilson@the-wire.com> - 2011-12-23 11:27 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 05:52 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Neil Cerutti <neilc@norwich.edu> - 2011-12-23 17:03 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-24 08:25 +0000
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 06:08 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Devin Jeanpierre <jeanpierreda@gmail.com> - 2011-12-24 18:25 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] alex23 <wuwei23@gmail.com> - 2011-12-24 16:10 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Devin Jeanpierre <jeanpierreda@gmail.com> - 2011-12-24 19:32 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] rusi <rustompmody@gmail.com> - 2011-12-24 19:22 -0800
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Lie Ryan <lie.1296@gmail.com> - 2011-12-25 15:12 +1100
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Devin Jeanpierre <jeanpierreda@gmail.com> - 2011-12-23 19:24 -0500
                Re: Early and late binding [was Re: what does 'a=b=c=[]' do] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-24 08:26 +0000
        Re: what does 'a=b=c=[]' do Ethan Furman <ethan@stoneleaf.us> - 2011-12-23 00:38 -0800
    Re: what does 'a=b=c=[]' do Ethan Furman <ethan@stoneleaf.us> - 2011-12-22 05:20 -0800
    Re: what does 'a=b=c=[]' do Eric <einazaki668@yahoo.com> - 2011-12-22 19:46 -0800
  Re: what does 'a=b=c=[]' do Lie Ryan <lie.1296@gmail.com> - 2011-12-24 21:30 +1100
  Re: what does 'a=b=c=[]' do Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-24 19:49 +0100

csiph-web