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RE: Newbie: static typing?

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Rui Maciel wrote:
> Chris Angelico wrote:
> 
> > On Tue, Aug 6, 2013 at 10:01 AM, Rui Maciel <rui.maciel@gmail.com> wrote:
> >> It would be nice if some functions threw an error if they were passed a
> >> type
> >> they don't support or weren't designed to handle.  That would avoid
> >> having to deal with some bugs which otherwise would never happen.
> >>
> >> To avoid this sort of error, I've been testing arguments passed to some
> >> functions based on their type, and raising TypeError when necessariy, but
> >> surely there must be a better, more pythonic way to handle this issue.
> >
> > def add_three_values(x,y,z):
> >     return x+y+z
> >
> > Do you want to test these values for compatibility? Remember, you
> > could take a mixture of types, as most of the numeric types can safely
> > be added. You can also add strings, or lists, but you can't mix them.
> > And look! It already raises TypeError if it's given something
> > unsuitable:
> 
> If the type problems aren't caught right away when the invalid types are
> passed to a function then the problem may only manifest itself in some far
> away point in the code, making this bug needlessly harder to spot and fix,
> and making the whole ordeal needlessly too time consuming.
> 
> 
> Rui Maciel

This can be true, but in personal experience does not happen 
often. I will say that dynamic typing ends up usually
being more future proof as I can later create a similar object
(but not in the same inheritance hierarchy) that will work
with older functions because the functions don't look for
certain types but rather just rely on duck typing.

I find this especially useful when testing or mocking. I can
create a test object and attach methods/attributes to the
test object to duck type as I desire to test the my desired code. 

I think the following reads are very interesting
for people new to Python from other languages (not just Java).
http://dirtsimple.org/2004/12/python-is-not-java.html
(and the flip side) http://dirtsimple.org/2004/12/java-is-not-python-either.html


~Ramit



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Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-05 21:46 +0100
  Re: Newbie: static typing? Gary Herron <gary.herron@islandtraining.com> - 2013-08-05 14:07 -0700
    Re: Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-06 10:05 +0100
      Re: Newbie: static typing? Steven D'Aprano <steve@pearwood.info> - 2013-08-06 09:26 +0000
      Re: Newbie: static typing? Joshua Landau <joshua@landau.ws> - 2013-08-06 10:29 +0100
        Re: Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-06 11:12 +0100
          Re: Newbie: static typing? Burak Arslan <burak.arslan@arskom.com.tr> - 2013-08-06 16:27 +0300
          Re: Newbie: static typing? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-08-06 15:57 +0200
          Re: Newbie: static typing? Chris Angelico <rosuav@gmail.com> - 2013-08-06 15:06 +0100
          Re: Newbie: static typing? "Eric S. Johansson" <esj@harvee.org> - 2013-08-06 09:58 -0400
          Re: Newbie: static typing? Chris Angelico <rosuav@gmail.com> - 2013-08-06 15:38 +0100
      Easier to Ask Forgiveness than Permission (was: Newbie: static typing?) Ben Finney <ben+python@benfinney.id.au> - 2013-08-07 08:23 +1000
  Re: Newbie: static typing? Ian Kelly <ian.g.kelly@gmail.com> - 2013-08-05 17:38 -0600
  Re: Newbie: static typing? Ben Finney <ben+python@benfinney.id.au> - 2013-08-06 10:35 +1000
    Re: Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-06 10:01 +0100
      Re: Newbie: static typing? Joshua Landau <joshua@landau.ws> - 2013-08-06 10:19 +0100
        Re: Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-06 11:07 +0100
          Re: Newbie: static typing? Rotwang <sg552@hotmail.co.uk> - 2013-08-06 15:25 +0100
          Re: Newbie: static typing? Ben Finney <ben+python@benfinney.id.au> - 2013-08-07 08:34 +1000
      Re: Newbie: static typing? Chris Angelico <rosuav@gmail.com> - 2013-08-06 10:29 +0100
        Re: Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-06 11:28 +0100
          Re: Newbie: static typing? Chris Angelico <rosuav@gmail.com> - 2013-08-06 11:50 +0100
          Re: Newbie: static typing? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-08-06 18:54 -0400
          Re: Newbie: static typing? Terry Reedy <tjreedy@udel.edu> - 2013-08-06 19:02 -0400
          Re: Newbie: static typing? Chris Angelico <rosuav@gmail.com> - 2013-08-07 01:16 +0100
          RE: Newbie: static typing? "Prasad, Ramit" <ramit.prasad@jpmorgan.com.dmarc.invalid> - 2013-08-08 16:46 +0000
  Re: Newbie: static typing? Steven D'Aprano <steve@pearwood.info> - 2013-08-06 05:21 +0000
    Re: Newbie: static typing? Rui Maciel <rui.maciel@gmail.com> - 2013-08-06 10:04 +0100
  Re: Newbie: static typing? Grant Edwards <invalid@invalid.invalid> - 2013-08-06 15:05 +0000

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