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Groups > comp.lang.python > #61006

Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers?

Date 2013-12-04 11:29 +0100
From Antoon Pardon <antoon.pardon@rece.vub.ac.be>
Subject Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers?
References (2 earlier) <eb15e1a8-49b1-4d55-a864-141efc65394e@googlegroups.com> <17gt99hg615jfm7bdid26185884d2pfdkf@4ax.com> <080d6a56-588b-425f-8968-8f77bc330427@googlegroups.com> <mailman.3546.1386147492.18130.python-list@python.org> <549180f1-fb98-4b59-b92f-5beceb1a6fb5@googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.3552.1386152954.18130.python-list@python.org> (permalink)

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Op 04-12-13 11:09, rusi schreef:
> On Wednesday, December 4, 2013 2:27:28 PM UTC+5:30, Ian wrote:
>> On Tue, Dec 3, 2013 at 11:31 PM, rusi  wrote:
>>> Its a more fundamental problem than that:
>>> It emerges from the OP's second post) that he wants '-' in the attributes.
>>> Is that all?
>>>
>>> Where does this syntax-enlargement stop? Spaces? Newlines?
>>
>> At non-strings.
>>
>>>>> setattr(foo, 21+21, 42)
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in <module>
>> TypeError: attribute name must be string, not 'int'
> 
> Not sure what's your point. 
> 
> OP wants attribute identifiers like outer_fieldset-inner_fieldset-third_field.
> Say I have a python expression: 
> obj.outer_fieldset-inner_fieldset-third_field
> 
> It can (in the proposed extension) be parsed as above, or as:
> obj.outer_fieldset - inner_fieldset-third_field
> the first hyphen being minus and the second being part of the identifier.
> 
> How do we decide which '-' are valid identifier components -- hyphens
> and which minus-signs?
> 
> So to state my point differently:
> The grammar of python is well-defined
> It has a 'sub-grammar' of strings that is completely* free-for-all ie just
> about anything can be put into a string literal.
> The border between the orderly and the wild world are the quote-marks.
> Remove that border and you get complete grammatical chaos.
> [Maybe I should have qualified my reference to 'spaces'.
> Algol-68 allowed spaces in identifiers (for readability!!)
> The result was chaos]
> 
> I used the spaces case to indicate the limit of chaos. Other characters (that
> already have uses) are just as problematic.

I don't agree with the latter. As it is now python can make the
distinction between

from A import B    and     fromAimportB.

I see no a priori reason why this should be limited to letters. A
language designer might choose to allow a bigger set of characters
in identifiers like '-', '+' and others. In that case a-b would be
an identifier and a - b would be the operation. Just as in python
fromAimportB is an identifier and from A import B is an import
statement.

-- 
Antoon Pardon

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Thread

Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-03 09:14 -0800
  Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ned Batchelder <ned@nedbatchelder.com> - 2013-12-03 12:38 -0500
  Re: Why is there no natural syntax for accessing attributes with names
 not being valid identifiers? Dave Angel <davea@davea.name> - 2013-12-03 12:48 -0500
    Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 14:05 -0800
      Re: Why is there no natural syntax for accessing attributes with
 names not being valid identifiers? Dave Angel <davea@davea.name> - 2013-12-04 17:28 -0500
  Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-03 09:31 -0800
    Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-03 15:49 -0800
  Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? random832@fastmail.us - 2013-12-03 13:03 -0500
    Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-03 15:47 -0800
      Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Tim Chase <python.list@tim.thechases.com> - 2013-12-03 19:06 -0600
        Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 12:35 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-04 20:46 +0000
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Jerry Hill <malaclypse2@gmail.com> - 2013-12-04 15:58 -0500
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 13:02 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Neil Cerutti <neilc@norwich.edu> - 2013-12-04 21:41 +0000
            Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 13:54 -0800
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Neil Cerutti <neilc@norwich.edu> - 2013-12-06 14:07 +0000
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-06 08:51 -0800
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Rotwang <sg552@hotmail.co.uk> - 2013-12-07 00:47 +0000
            Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 14:13 -0800
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 15:09 -0800
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 15:57 -0800
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 16:26 -0800
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ned Batchelder <ned@nedbatchelder.com> - 2013-12-04 20:17 -0500
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Terry Reedy <tjreedy@udel.edu> - 2013-12-04 21:58 -0500
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 19:05 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Steven D'Aprano <steve@pearwood.info> - 2013-12-05 07:56 +0000
      Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Tim Roberts <timr@probo.com> - 2013-12-03 21:45 -0800
        Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? rusi <rustompmody@gmail.com> - 2013-12-03 22:31 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ian Kelly <ian.g.kelly@gmail.com> - 2013-12-04 01:57 -0700
            Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? rusi <rustompmody@gmail.com> - 2013-12-04 02:09 -0800
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-12-04 11:29 +0100
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? rusi <rustompmody@gmail.com> - 2013-12-04 04:01 -0800
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-12-04 13:32 +0100
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? rusi <rustompmody@gmail.com> - 2013-12-04 05:02 -0800
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-12-04 20:57 +0100
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Chris Angelico <rosuav@gmail.com> - 2013-12-04 21:33 +1100
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? rusi <rustompmody@gmail.com> - 2013-12-04 03:27 -0800
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Tim Chase <python.list@tim.thechases.com> - 2013-12-04 05:25 -0600
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-12-04 13:30 +0200
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Chris Angelico <rosuav@gmail.com> - 2013-12-04 22:40 +1100
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 07:56 -0800
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ian Kelly <ian.g.kelly@gmail.com> - 2013-12-04 19:43 -0700
                Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? rusi <rustompmody@gmail.com> - 2013-12-04 20:48 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-04 19:27 -0500
            Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Roy Smith <roy@panix.com> - 2013-12-04 20:03 -0500
        Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 01:12 -0800
        Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Roy Smith <roy@panix.com> - 2013-12-04 08:23 -0500
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 13:00 -0800
        Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 12:07 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 12:22 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-12-04 20:55 +0000
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Ethan Furman <ethan@stoneleaf.us> - 2013-12-04 13:00 -0800
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Terry Reedy <tjreedy@udel.edu> - 2013-12-04 17:11 -0500
            Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Piotr Dobrogost <p@google-groups-2013.dobrogost.net> - 2013-12-04 15:42 -0800
              Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Terry Reedy <tjreedy@udel.edu> - 2013-12-04 22:21 -0500
          Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers? Rotwang <sg552@hotmail.co.uk> - 2013-12-05 01:50 +0000

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