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Groups > comp.lang.python > #90285

Re: functions, optional parameters

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On 05/09/2015 11:33 PM, Chris Angelico wrote:
> On Sun, May 10, 2015 at 12:45 PM, Steven D'Aprano
> <steve+comp.lang.python@pearwood.info> wrote:
>> This is the point where some people try to suggest some sort of complicated,
>> fragile, DWIM heuristic where the compiler tries to guess whether the user
>> actually wants the default to use early or late binding, based on what the
>> expression looks like. "0 is an immutable int, use early binding; [] is a
>> mutable list, use late binding." sort of thing. Such a thing might work
>> well for the obvious cases, but it would be a bugger to debug and
>> work-around for the non-obvious cases when it guesses wrong -- and it will.
>
> What you could have is "late-binding semantics, optional early binding
> as an optimization but only in cases where the result is
> indistinguishable". That would allow common cases (int/bool/str/None
> literals) to be optimized, since there's absolutely no way for them to
> evaluate differently.
>

Except for literals, True, False and None, I can't see any way to 
optimize such a thing.  Just because the name on the right side 
references an immutable object at compile time, it doesn't follow that 
it'll still be the same object later.

Unless late binding means something very different than I understood.

-- 
DaveA

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functions, optional parameters Michael Welle <mwe012008@gmx.net> - 2015-05-08 13:59 +0200
  Re: functions, optional parameters Rustom Mody <rustompmody@gmail.com> - 2015-05-08 05:09 -0700
    Re: functions, optional parameters Michael Welle <mwe012008@gmx.net> - 2015-05-08 14:36 +0200
  Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-08 22:39 +1000
    Re: functions, optional parameters Michael Welle <mwe012008@gmx.net> - 2015-05-08 14:57 +0200
  Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-09 01:24 +1000
    Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-09 02:02 +1000
      Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-09 03:36 +1000
        Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-09 03:49 +1000
          Re: functions, optional parameters Mel Wilson <mwilson@the-wire.com> - 2015-05-08 18:49 +0000
          Re: functions, optional parameters Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-05-09 13:41 +1200
            Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-09 12:05 +1000
              Re: functions, optional parameters Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-05-09 19:27 +1200
          Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-09 12:52 +1000
    Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-09 03:26 +1000
    Re: functions, optional parameters Michael Welle <mwe012008@gmx.net> - 2015-05-08 17:50 +0200
      Re: functions, optional parameters Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-09 10:57 -0600
      Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-10 13:33 +1000
        Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-10 15:20 +1000
          Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-10 18:59 +1000
      Re: functions, optional parameters Rustom Mody <rustompmody@gmail.com> - 2015-05-09 20:35 -0700
        Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-10 15:25 +1000
      Re: functions, optional parameters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-10 12:45 +1000
        Re: functions, optional parameters Dave Angel <davea@davea.name> - 2015-05-10 07:25 -0400
        Re: functions, optional parameters Chris Angelico <rosuav@gmail.com> - 2015-05-11 00:39 +1000
        Re: functions, optional parameters Michael Welle <mwe012008@gmx.net> - 2015-05-11 07:58 +0200
    Re: functions, optional parameters Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-08 09:48 -0600

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