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Re: python 3.3 repr

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Subject Re: python 3.3 repr
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Date Fri, 15 Nov 2013 09:25:48 -0500
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In article <b6db8982-feac-4036-8ec4-2dc720d41a4b@googlegroups.com>,
Ned Batchelder <ned@nedbatchelder.com> wrote:

> In Python3, repr() will return a Unicode string, and will preserve existing 
> Unicode characters in its arguments.  This has been controversial.  To get 
> the Python 2 behavior of a pure-ascii representation, there is the new 
> builtin ascii(), and a corresponding %a format string.

I'm still stuck on Python 2, and while I can understand the controversy ("It breaks my Python 2 code!"), this seems like the right thing to have done.  In Python 2, unicode is an add-on.  One of the big design drivers in Python 3 was to make unicode the standard.

The idea behind repr() is to provide a "just plain text" representation of an object.  In P2, "just plain text" means ascii, so escaping non-ascii characters makes sense.  In P3, "just plain text" means unicode, so escaping non-ascii characters no longer makes sense.

Some of us have been doing this long enough to remember when "just plain text" meant only a single case of the alphabet (and a subset of ascii punctuation).  On an ASR-33, your C program would print like:

MAIN() \(
	PRINTF("HELLO, ASCII WORLD");
\)

because ASR-33's didn't have curly braces (or lower case).

Having P3's repr() escape non-ascii characters today makes about as much sense as expecting P2's repr() to escape curly braces (and vertical bars, and a few others) because not every terminal can print those.

--
Roy Smith
roy@panix.com

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python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 11:28 +0000
  Re: python 3.3 repr Ned Batchelder <ned@nedbatchelder.com> - 2013-11-15 03:38 -0800
    Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 12:16 +0000
      Re: python 3.3 repr Ned Batchelder <ned@nedbatchelder.com> - 2013-11-15 05:54 -0800
        Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 14:29 +0000
        Re: python 3.3 repr Serhiy Storchaka <storchaka@gmail.com> - 2013-11-15 16:40 +0200
        Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 14:52 +0000
    Re: python 3.3 repr Roy Smith <roy@panix.com> - 2013-11-15 09:25 -0500
    Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 14:43 +0000
      Re: python 3.3 repr Ned Batchelder <ned@nedbatchelder.com> - 2013-11-15 07:08 -0800
        Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 15:39 +0000
        Re: python 3.3 repr Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-11-15 16:49 +0100
        Re: python 3.3 repr Chris Angelico <rosuav@gmail.com> - 2013-11-16 03:01 +1100
          Re: python 3.3 repr Neil Cerutti <neilc@norwich.edu> - 2013-11-15 17:47 +0000
            Re: python 3.3 repr Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-16 01:09 +0000
      Re: python 3.3 repr Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-15 17:10 +0000
        Re: python 3.3 repr Chris Angelico <rosuav@gmail.com> - 2013-11-16 04:29 +1100
        Re: python 3.3 repr Cousin Stanley <cousinstanley@gmail.com> - 2013-11-15 10:45 -0700
    Re: python 3.3 repr Joel Goldstick <joel.goldstick@gmail.com> - 2013-11-15 09:50 -0500
    Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 15:03 +0000
    Re: python 3.3 repr Joel Goldstick <joel.goldstick@gmail.com> - 2013-11-15 10:07 -0500
    Re: python 3.3 repr Chris Angelico <rosuav@gmail.com> - 2013-11-16 02:08 +1100
    Re: python 3.3 repr Robin Becker <robin@reportlab.com> - 2013-11-15 15:18 +0000
    Re: python 3.3 repr Roy Smith <roy@panix.com> - 2013-11-15 10:32 -0500
    Re: python 3.3 repr William Ray Wing <wrw@mac.com> - 2013-11-15 11:30 -0500
    Re: python 3.3 repr Zero Piraeus <z@etiol.net> - 2013-11-15 14:06 -0300
    Re: python 3.3 repr Chris Angelico <rosuav@gmail.com> - 2013-11-16 04:11 +1100
    Re: python 3.3 repr Serhiy Storchaka <storchaka@gmail.com> - 2013-11-15 19:37 +0200
  Re: python 3.3 repr Gene Heskett <gheskett@wdtv.com> - 2013-11-15 11:36 -0500
  Re: python 3.3 repr Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-11-15 17:58 +0000
  Re: python 3.3 repr Gene Heskett <gheskett@wdtv.com> - 2013-11-15 14:23 -0500

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