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Re: a little parsing challenge ☺

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Ian Kelly wrote:

> Billy Mays wrote:
>> I gave it a shot.  It doesn't do any of the Unicode delims, because let's
>> face it, Unicode is for goobers.
> 
> Uh, okay...
> 
> Your script also misses the requirement of outputting the index or row
> and column of the first mismatched bracket.

Thanks to Python's expressiveness, this can be easily remedied (see below).  

I also do not follow Billy's comment about Unicode.  Unicode and the fact 
that Python supports it *natively* cannot be appreciated enough in a 
globalized world.

However, I have learned a lot about being pythonic from his posting (take 
those generator expressions, for example!), and the idea of looking at the 
top of a stack for reference is a really good one.  Thank you, Billy!

Here is my improvement of his code, which should fill the mentioned gaps.
I have also reversed the order in the report line as I think it is more 
natural this way.  I have tested the code superficially with a directory 
containing a single text file.  Watch for word-wrap:

# encoding: utf-8
'''
Created on 2011-07-18

@author: Thomas 'PointedEars' Lahn <PointedEars@web.de>, based on an idea of
Billy Mays <81282ed9a88799d21e77957df2d84bd6514d9af6@myhashismyemail.com>
in <news:j01ph6$knt$1@speranza.aioe.org> 
'''
import sys, os

pairs = {u'}': u'{', u')': u'(', u']': u'[',
         u'”': u'“', u'›': u'‹', u'»': u'«',
         u'】': u'【', u'〉': u'〈', u'》': u'《',
         u'」': u'「', u'』': u'『'}
valid = set(v for pair in pairs.items() for v in pair)

if __name__ == '__main__':
    for dirpath, dirnames, filenames in os.walk(sys.argv[1]):
        for name in filenames:
            stack = [' ']

            # you can use chardet etc. instead 
            encoding = 'utf-8'

            with open(os.path.join(dirpath, name), 'r') as f:
                reported = False
                chars = ((c, line_no, col) for line_no, line in enumerate(f) 
for col, c in enumerate(line.decode(encoding)) if c in valid)
                for c, line_no, col in chars:
                    if c in pairs:
                        if stack[-1] == pairs[c]:
                            stack.pop()
                        else:
                            if not reported:
                                first_bad = (c, line_no + 1, col + 1)
                                reported = True
                    else:
                        stack.append(c)

            print '%s: %s' % (name, ("good" if len(stack) == 1 else "bad 
'%s' at %s:%s" % first_bad))

-- 
PointedEars

Bitte keine Kopien per E-Mail. / Please do not Cc: me.

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Thread

a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-17 00:47 -0700
  Re: a little parsing challenge ☺ Raymond Hettinger <python@rcn.com> - 2011-07-17 02:48 -0700
    Re: a little parsing challenge ☺ Robert Klemme <shortcutter@googlemail.com> - 2011-07-17 15:20 +0200
      Re: a little parsing challenge ☺ mhenn <michihenn@hotmail.com> - 2011-07-17 15:55 +0200
        Re: a little parsing challenge ☺ Robert Klemme <shortcutter@googlemail.com> - 2011-07-17 18:01 +0200
          Re: a little parsing challenge ☺ Robert Klemme <shortcutter@googlemail.com> - 2011-07-17 18:54 +0200
    Re: a little parsing challenge ☺ Thomas Boell <tboell@domain.invalid> - 2011-07-17 17:49 +0200
      Re: a little parsing challenge ☺ Raymond Hettinger <python@rcn.com> - 2011-07-17 12:16 -0700
    Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-18 07:39 -0700
      Re: a little parsing challenge ☺ Robert Klemme <shortcutter@googlemail.com> - 2011-07-20 08:23 +0200
      Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-20 03:31 -0700
        Re: a little parsing challenge ☺ "Uri Guttman" <uri@StemSystems.com> - 2011-07-20 12:31 -0400
          Re: a little parsing challenge ☺ rusi <rustompmody@gmail.com> - 2011-07-20 10:30 -0700
          Re: a little parsing challenge ☺ merlyn@stonehenge.com (Randal L. Schwartz) - 2011-07-20 12:06 -0700
            Re: a little parsing challenge ☺ Jason Earl <jearl@notengoamigos.org> - 2011-07-20 14:57 -0600
    Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-19 09:54 -0700
      Re: a little parsing challenge ☺ Thomas Jollans <t@jollybox.de> - 2011-07-19 20:07 +0200
        Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-21 05:58 -0700
          Re: a little parsing challenge ☺ Ian Kelly <ian.g.kelly@gmail.com> - 2011-07-21 08:26 -0600
            Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-21 08:36 -0700
              Re: a little parsing challenge ☺ python@bdurham.com - 2011-07-21 12:43 -0400
                Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-21 11:53 -0700
                Re: a little parsing challenge ☺ Terry Reedy <tjreedy@udel.edu> - 2011-07-21 18:37 -0400
          Re: a little parsing challenge ☺ John O'Hagan <research@johnohagan.com> - 2011-07-25 15:57 +1000
      Re: a little parsing challenge ☺ Ian Kelly <ian.g.kelly@gmail.com> - 2011-07-19 12:08 -0600
  Re: a little parsing challenge ☺ Chris Angelico <rosuav@gmail.com> - 2011-07-17 21:34 +1000
    Re: a little parsing challenge ☺ rusi <rustompmody@gmail.com> - 2011-07-17 04:52 -0700
    Re: a little parsing challenge ☺ Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-07-17 16:15 +0200
      Re: a little parsing challenge ☺ Raymond Hettinger <python@rcn.com> - 2011-07-17 12:18 -0700
        Re: a little parsing challenge ☺ Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-07-17 22:16 +0200
          Re: a little parsing challenge ☺ Thomas Jollans <t@jollybox.de> - 2011-07-17 22:57 +0200
      Re: a little parsing challenge ☺ Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-07-17 23:43 +0200
      Re: a little parsing challenge ☺ Rouslan Korneychuk <rouslank@msn.com> - 2011-07-18 03:09 -0400
        Re: a little parsing challenge ☺ Stefan Behnel <stefan_ml@behnel.de> - 2011-07-18 09:24 +0200
          Re: a little parsing challenge ☺ Rouslan Korneychuk <rouslank@msn.com> - 2011-07-18 04:04 -0400
        Re: a little parsing challenge ☺ Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-07-18 18:46 +0200
          Re: a little parsing challenge ☺ Rouslan Korneychuk <rouslank@msn.com> - 2011-07-18 14:14 -0400
        Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-21 06:23 -0700
          Re: a little parsing challenge ☺ Rouslan Korneychuk <rouslank@msn.com> - 2011-07-21 17:54 -0400
  Re: a little parsing challenge ☺ gene heskett <gheskett@wdtv.com> - 2011-07-17 10:26 -0400
  Re: a little parsing challenge ☺ Thomas Jollans <t@jollybox.de> - 2011-07-17 08:31 -0700
    Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-19 10:49 -0700
      Re: a little parsing challenge ☺ Thomas Jollans <t@jollybox.de> - 2011-07-19 20:14 +0200
        Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-21 05:29 -0700
          Re: a little parsing challenge ☺ Thomas Jollans <t@jollybox.de> - 2011-07-21 15:21 +0200
      Re: a little parsing challenge ☺ Thomas Jollans <t@jollybox.de> - 2011-07-19 20:17 +0200
  Re: a little parsing challenge ☺ rantingrick <rantingrick@gmail.com> - 2011-07-17 18:52 -0700
  Re: a little parsing challenge ☺ Billy Mays <81282ed9a88799d21e77957df2d84bd6514d9af6@myhashismyemail.com> - 2011-07-18 13:12 -0400
    Re: a little parsing challenge ☺ Ian Kelly <ian.g.kelly@gmail.com> - 2011-07-18 12:10 -0600
      Re: a little parsing challenge ☺ Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-07-18 23:59 +0200
        Re: a little parsing challenge ☺ Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-07-19 08:09 +0200
        Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-19 10:32 -0700
    Re: a little parsing challenge ☺ Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-19 09:56 +1000
      Re: a little parsing challenge ☺ Billy Mays <noway@nohow.com> - 2011-07-18 22:07 -0400
        Re: a little parsing challenge ☺ rusi <rustompmody@gmail.com> - 2011-07-18 19:50 -0700
          Re: a little parsing challenge ☺ Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-19 13:11 +1000
            Re: a little parsing challenge ☺ rusi <rustompmody@gmail.com> - 2011-07-18 21:59 -0700
              Re: a little parsing challenge ☺ Chris Angelico <rosuav@gmail.com> - 2011-07-19 15:36 +1000
        Re: a little parsing challenge ☺ MRAB <python@mrabarnett.plus.com> - 2011-07-19 04:08 +0100
        Re: a little parsing challenge ☺ Benjamin Kaplan <benjamin.kaplan@case.edu> - 2011-07-18 20:54 -0700
        Re: a little parsing challenge ☺ Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-19 14:30 +1000
        Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-19 01:58 -0700
    Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-19 10:14 -0700
      Re: a little parsing challenge ☺ Billy Mays <81282ed9a88799d21e77957df2d84bd6514d9af6@myhashismyemail.com> - 2011-07-19 13:33 -0400
        Re: a little parsing challenge ☺ Xah Lee <xahlee@gmail.com> - 2011-07-19 11:12 -0700
          Re: a little parsing challenge ☺ Terry Reedy <tjreedy@udel.edu> - 2011-07-19 15:09 -0400
            Re: a little parsing challenge ☺ jmfauth <wxjmfauth@gmail.com> - 2011-07-19 23:29 -0700
              Re: a little parsing challenge ☺ Ian Kelly <ian.g.kelly@gmail.com> - 2011-07-20 01:29 -0600
                Re: a little parsing challenge ☺ jmfauth <wxjmfauth@gmail.com> - 2011-07-20 00:54 -0700
                Re: a little parsing challenge ☺ Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-20 18:18 +1000
  Re: a little parsing challenge ? sln@netherlands.com - 2011-07-18 12:34 -0700
  Re: a little parsing challenge ☺ Mark Tarver <dr.mtarver@gmail.com> - 2011-07-19 22:43 -0700

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