Guido van Rossum wrote:
> On Jan 25, 2008 10:01 AM, Leif Walsh <[EMAIL PROTECTED]> wrote:
>> On Jan 25, 2008 12:37 PM, Christian Heimes <[EMAIL PROTECTED]> wrote:
>>> The pipe char is ambiguous because is no direction. It was suggested and
>>> rejected last year.
>> Out of almost-pure devil's advocacy, has <> been considered? My first
>> instinct is that it would be ambiguous with less-than/greater-than,
>> but if someone can convince me otherwise, might it work? After all,
>> it's the only other balanced pair of punctuation I see on my keyboard.
>
> No, there are too many syntactic situations where this would make the
> grammar ambiguous or tortuous. We don't want to move beyond LL(1).
> (Apart from parsing indentation and nested parentheses, of course --
> which actually reminds me or another issue with using <> as brackets:
> the lexer can't know whether a particular < or > is used as a bracket
> or not, so it can't keep track of nesting like it does for (), [] and
> {}. So <> would always remain a second-class citizen.)
>
Hmm, I guess both of those objections apply to using | as the delimiter
as well. Ah well.
If anyone has a bit of free time to play with, it will probably be worth
creating a retrospective PEP for the set literal syntax to capture the
rationale for the various design decisions like:
- why not || or <> as the delimeters?
- why {} continues as the empty dict
- why {1, 2, 3} is immutable, while {1:2} is not
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://www.boredomandlaziness.org
_______________________________________________
Python-3000 mailing list
Python-3000@python.org
http://mail.python.org/mailman/listinfo/python-3000
Unsubscribe:
http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
