[Python-3000] Support for PEP 3131

["Martin v. Löwis"]

> You've got this backwards, and I suspect that's part of the root of
> the disagreement.  It's not that "when humans enter the loop they
> cause problems."  The purpose of the language is to *serve humans*.
> Without humans, we would just use machine code instead of Python.
> If it doesn't work for humans, it's not because the humans are broken,
> the language is broken.
> 
> The grammar has to be something a human can understand.

Indeed, it is easy for a human to still understand the Py3k grammar.
An identifier starts with a letter, followed by letters and digits.
It's really the same rule that was in use all the time.

It's not easy for a single human to memorize the entire *language*,
and never was. The language is not just about the syntax: it's
also about the library. While there are many details of the library
that you can memorize, I bet nobody could enumerate all classes,
functions, methods, symbolic constants etc in the entire library;
this causes no concern for people.

> If we are going to allow Unicode identifiers at all, then I would
> recommend only allowing identifiers that are already normalized
> (in NFC).

In what way would that be an improvement compared to what the PEP
already says?

>     2.  "python" allows only ASCII identifiers.  "python -U" allows
>         Unicode identifiers that are in NFC and use a conservative,
>         *fixed* subset of the available characters.  Support for
>         "-U" is a compile-time option, preferably not compiled into
>         official binary releases of Python.
> 
>     3.  "python" and "python -U" are as above.  "python -UU" allows
>         all Unicode identifier characters (which may grow over time
>         as the Unicode standard changes).  Support for "-UU" is a
>         compile-time option, never on in official binary releases of
>         Python, and discouraged with "here be dragons" warnings, etc.

This would cripple the feature, so I'm -1.

Regards,
Martin