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Re: Bools and explicitness [was Re: PyWart: The problem with "print"]

Newsgroups comp.lang.python
Date 2013-06-06 11:08 -0700
References (8 earlier) <mailman.2747.1370451556.3114.python-list@python.org> <96cd7a31-40ce-4e51-9489-446b7f002a0e@googlegroups.com> <51afec46$0$29966$c3e8da3$5496439d@news.astraweb.com> <mailman.2783.1370485793.3114.python-list@python.org> <51b0565d$0$11118$c3e8da3@news.astraweb.com>
Message-ID <94f20dce-3d2a-4817-9ca9-22ce5823809d@googlegroups.com> (permalink)
Subject Re: Bools and explicitness [was Re: PyWart: The problem with "print"]
From "Russ P." <Russ.Paielli@gmail.com>

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On Thursday, June 6, 2013 2:29:02 AM UTC-7, Steven D'Aprano wrote:
> On Thu, 06 Jun 2013 12:29:44 +1000, Chris Angelico wrote:
> 
> 
> 
> > On Thu, Jun 6, 2013 at 11:56 AM, Steven D'Aprano
> 
> > <steve+comp.lang.python@pearwood.info> wrote:
> 
> >> On Wed, 05 Jun 2013 14:59:31 -0700, Russ P. wrote:
> 
> >>> As for Python, my experience with it is that, as your application
> 
> >>> grows, you start getting confused about what the argument types are or
> 
> >>> are supposed to be.
> 
> >>
> 
> >> Whereas people never get confused about the arguments in static typed
> 
> >> languages?
> 
> >>
> 
> >> The only difference is whether the compiler tells you that you've
> 
> >> passed the wrong type, or your unit test tells you that you've passed
> 
> >> the wrong type. What, you don't have unit tests? Then how do you know
> 
> >> that the code does the right thing when passed data of the right type?
> 
> >> Adding an extra couple of unit tests is not that big a burden.
> 
> > 
> 
> > The valid type(s) for an argument can be divided into two categories:
> 
> > Those the compiler can check for, and those the compiler can't check
> 
> > for. Some languages have more in the first category than others, but
> 
> > what compiler can prove that a string is an
> 
> > HTML-special-characters-escaped string? In a very few languages, the
> 
> > compiler can insist that an integer be between 7 and 30, but there'll
> 
> > always be some things you can't demonstrate with a function signature.
> 
> > 
> 
> > That said, though, I do like being able to make at least *some*
> 
> > declaration there. It helps catch certain types of error.
> 
> 
> 
> *shrug*
> 
> 
> 
> I don't terribly miss type declarations. Function argument declarations 
> 
> are a bit simpler in Pascal, compared to Python:
> 
> 
> 
> 
> 
> Function Add(A, B : Integer) : Integer; 
> 
> Begin
> 
>  Add := A + B;
> 
> End;
> 
> 
> 
> 
> 
> versus
> 
> 
> 
> 
> 
> def add(a, b):
> 
>     if not (isinstance(a, int) and isinstance(b, int)):
> 
>         raise TypeError
> 
>     return a + b
> 

Scala also has isInstanceOf[Type] which allows you to do this sort of thing, but of course it would be considered terrible style in Scala.

> 
> 
> 
> but not that much simpler. And while Python can trivially support 
> 
> multiple types, Pascal cannot. (Some other static typed languages may.)
> 
> 
> 
> Whatever benefit there is in declaring the type of a function is lost due 
> 
> to the inability to duck-type or program to an interface. There's no type 
> 
> that says "any object with a 'next' method", for example. And having to 
> 
> declare local variables is a PITA with little benefit.
> 
> 
> 
> Give me a language with type inference, and a nice, easy way to keep duck-
> 
> typing, and I'll reconsider. But until then, I don't believe the benefit 
> 
> of static types comes even close to paying for the extra effort.


Scala has type inference. For example, you can write

val x = 1

and the compiler figures out that x is an integer. Scala also has something called structural typing, which I think is more or less equivalent to "duck typing," although I don't think it is used very often.

Are you ready to try Scala yet? 8-)

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Thread

PyWart: The problem with "print" Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-02 10:04 -0700
  Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-03 03:20 +1000
    Re: PyWart: The problem with "print" Dan Sommers <dan@tombstonezero.net> - 2013-06-02 17:49 +0000
      Re: PyWart: The problem with "print" Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-02 11:18 -0700
        Re: PyWart: The problem with "print" Ned Batchelder <ned@nedbatchelder.com> - 2013-06-02 16:45 -0400
        Re: PyWart: The problem with "print" Michael Torrie <torriem@gmail.com> - 2013-06-02 23:49 -0600
        Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-03 17:17 +1000
          Re: PyWart: The problem with "print" Alister <alister.ware@ntlworld.com> - 2013-06-03 08:01 +0000
    Re: PyWart: The problem with "print" Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-02 11:09 -0700
      Re: PyWart: The problem with "print" Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-02 19:03 +0000
      Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-03 06:21 +1000
      Re: PyWart: The problem with "print" jmfauth <wxjmfauth@gmail.com> - 2013-06-04 05:23 -0700
        Re: PyWart: The problem with "print" rusi <rustompmody@gmail.com> - 2013-06-04 06:29 -0700
          Re: PyWart: The problem with "print" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-04 14:35 +0100
        Re: PyWart: The problem with "print" Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-05 05:03 +0000
  Re: PyWart: The problem with "print" Andrew Berg <robotsondrugs@gmail.com> - 2013-06-02 12:30 -0500
  Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-03 03:34 +1000
  Re: PyWart: The problem with "print" Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-02 18:58 +0000
    Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-03 06:28 +1000
    Re: PyWart: The problem with "print" Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-03 18:37 -0700
      Re: PyWart: The problem with "print" Vito De Tullio <vito.detullio@gmail.com> - 2013-06-04 05:16 +0200
        Re: PyWart: The problem with "print" Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-03 20:53 -0700
        Re: PyWart: The problem with "print" Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-04 04:30 +0000
      Bools and explicitness [was Re: PyWart: The problem with "print"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-04 05:39 +0000
        Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-04 08:44 -0700
          Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-05 02:00 +1000
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-04 09:19 -0700
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-05 02:27 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-05 05:28 +0000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] alex23 <wuwei23@gmail.com> - 2013-06-04 22:31 -0700
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Ned Batchelder <ned@nedbatchelder.com> - 2013-06-04 13:25 -0400
          Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-04 09:09 -0700
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] alex23 <wuwei23@gmail.com> - 2013-06-04 18:31 -0700
          Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Fábio Santos <fabiosantosart@gmail.com> - 2013-06-04 17:10 +0100
          Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Jason Swails <jason.swails@gmail.com> - 2013-06-04 13:32 -0400
          Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-04 11:42 -0600
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-04 16:21 -0700
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-05 00:37 +0100
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Michael Torrie <torriem@gmail.com> - 2013-06-04 23:28 -0600
          Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-04 23:11 -0700
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-05 17:15 +1000
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-05 00:47 -0700
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-06 09:49 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-07 02:59 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Dan Stromberg <drsalists@gmail.com> - 2013-06-06 18:26 -0700
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-05 09:59 +0100
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-05 09:15 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-06 02:59 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-05 14:59 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-06 01:56 +0000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-06 12:29 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-05 21:25 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-06 00:06 -0600
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-06 09:29 +0000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-06 19:45 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Serhiy Storchaka <storchaka@gmail.com> - 2013-06-06 14:12 +0300
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Robert Kern <robert.kern@gmail.com> - 2013-06-06 16:35 +0100
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-07 01:41 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Robert Kern <robert.kern@gmail.com> - 2013-06-06 17:08 +0100
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] rusi <rustompmody@gmail.com> - 2013-06-06 10:27 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Devin Jeanpierre <jeanpierreda@gmail.com> - 2013-06-06 14:44 -0400
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Janssen <dreamingforward@gmail.com> - 2013-06-06 10:59 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] alex23 <wuwei23@gmail.com> - 2013-06-06 17:53 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Janssen <dreamingforward@gmail.com> - 2013-06-06 18:44 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] alex23 <wuwei23@gmail.com> - 2013-06-06 19:03 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Janssen <dreamingforward@gmail.com> - 2013-06-06 22:01 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-07 02:29 +0000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Janssen <dreamingforward@gmail.com> - 2013-06-06 20:14 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] rusi <rustompmody@gmail.com> - 2013-06-06 20:24 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Mark Janssen <dreamingforward@gmail.com> - 2013-06-06 20:30 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] rusi <rustompmody@gmail.com> - 2013-06-06 20:43 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-06 11:08 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-06 08:49 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-07 02:00 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Grant Edwards <invalid@invalid.invalid> - 2013-06-06 17:32 +0000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-06 01:37 +0000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-06 11:45 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] rusi <rustompmody@gmail.com> - 2013-06-06 07:09 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-07 01:26 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] rusi <rustompmody@gmail.com> - 2013-06-06 08:36 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Chris Angelico <rosuav@gmail.com> - 2013-06-07 01:46 +1000
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-06 11:03 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-06 11:11 -0700
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Terry Jan Reedy <tjreedy@udel.edu> - 2013-06-05 12:10 -0400
            Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Michael Torrie <torriem@gmail.com> - 2013-06-05 17:18 -0600
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] "Russ P." <Russ.Paielli@gmail.com> - 2013-06-05 16:52 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Michael Torrie <torriem@gmail.com> - 2013-06-05 19:20 -0600
              Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-06 09:24 -0700
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] Devin Jeanpierre <jeanpierreda@gmail.com> - 2013-06-06 12:39 -0400
                Re: Bools and explicitness [was Re: PyWart: The problem with "print"] alex23 <wuwei23@gmail.com> - 2013-06-06 17:55 -0700
      Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-04 17:30 +1000
  Re: PyWart: The problem with "print" Jason Swails <jason.swails@gmail.com> - 2013-06-02 20:16 -0400
    Re: PyWart: The problem with "print" Dan Sommers <dan@tombstonezero.net> - 2013-06-03 03:10 +0000
      Re: PyWart: The problem with "print" Jason Swails <jason.swails@gmail.com> - 2013-06-02 23:23 -0400
        Re: PyWart: The problem with "print" Dan Sommers <dan@tombstonezero.net> - 2013-06-03 04:20 +0000
          Re: PyWart: The problem with "print" Robert Kern <robert.kern@gmail.com> - 2013-06-03 11:52 +0100
      Re: PyWart: The problem with "print" Tim Delaney <timothy.c.delaney@gmail.com> - 2013-06-03 13:37 +1000
        Python Heisenbugs?  (was: Re: PyWart: The problem with "print") Dan Sommers <dan@tombstonezero.net> - 2013-06-03 04:34 +0000
          Re: Python Heisenbugs? (was: Re: PyWart: The problem with "print") Chris Angelico <rosuav@gmail.com> - 2013-06-03 15:05 +1000
          Re: Python Heisenbugs? (was: Re: PyWart: The problem with "print") Devin Jeanpierre <jeanpierreda@gmail.com> - 2013-06-03 03:06 -0400
      Re: PyWart: The problem with "print" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-03 09:49 +0100
      Re: PyWart: The problem with "print" Dave Angel <davea@davea.name> - 2013-06-03 08:56 -0400
  Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-03 12:02 +1000
  Re: PyWart: The problem with "print" Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-03 11:12 -0600
  Re: PyWart: The problem with "print" Jason Swails <jason.swails@gmail.com> - 2013-06-03 15:09 -0400
    Re: PyWart: The problem with "print" Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-03 20:31 +0000
      Re: PyWart: The problem with "print" Chris Angelico <rosuav@gmail.com> - 2013-06-04 06:44 +1000
  Re: PyWart: The problem with "print" Jason Swails <jason.swails@gmail.com> - 2013-06-03 15:10 -0400
  Re: PyWart: The problem with "print" Jason Swails <jason.swails@gmail.com> - 2013-06-03 15:11 -0400

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