[Python-Dev] str.format implementation

Eric V. Smith eric at trueblade.com
Tue Dec 13 17:31:41 CET 2011


On 12/12/2011 10:56 PM, Ben Wolfson wrote:
> Hi,
> 
> I'm hoping to get some kind of consensus about the divergences between
> the implementation and documentation of str.format
> (http://mail.python.org/pipermail/python-dev/2011-June/111860.html and
> the linked bug report contain examples of the divergences). These
> pertain to the arg_name, attribute_name, and element_index fields of
> the grammar in the docs:
> 
>     replacement_field ::=  "{" [field_name] ["!" conversion] [":"
> format_spec] "}"
>     field_name        ::=  arg_name ("." attribute_name | "["
> element_index "]")*
>     arg_name          ::=  [identifier | integer]
>     attribute_name    ::=  identifier
>     element_index     ::=  integer | index_string
>     index_string      ::=  <any source character except "]"> +
> 
> Nothing definitive emerged from the last round of discussion, and as
> far as I can recall there are now three proposals for what kind of
> changes might be worth making:
> 
>  (1) the implementation should conform to the docs;*
>  (2) like (1) with the change that element_index should be changed to
> "integer | identifier" (rendering index_string otiose);

I've now learned what "otiose" means. Thanks!

>  (3) like (1) with the change that index_string should be changed to
> '<any source character except "]", "}", or "{">'.

This is still on my plate. I just haven't had a lot of Python time
recently. But I do plan to address this.

Eric.



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