[Python-Dev] Support of UTF-16 and UTF-32 source encodings

[Stephen J. Turnbull]

Steve Dower writes:

 > Saying [UTF-16] is rarely used is rather exposing your own
 > unawareness though - it could arguably be the most commonly used
 > encoding (depending on how you define "used").

Because we're discussing the storage of .py files, the relevant
definition is the one used by the Unicode Standard, of course: a
text/plain stream intended to be manipulated by any conformant Unicode
processor that claims to handle text/plain.  File formats with in-band
formatting codes and allowing embedded non-text content like Word, or
operating system or stdlib APIs, don't count.  Nor have I seen UTF-16
used in email or HTML since the unregretted days of Win2k betas[1]
(but I don't frequent Windows- or Java-oriented sites, so I have to
admit my experience is limited in a possibly relevant way).

In Japan my impression is that modern versions of Windows have
Memopad[sic] configured to emit UTF-8-with-signature by default for
new files, and if not, the abomination known as Shift JIS (I'm not
sure if that is a user or OEM option, though).  Never a widechar
encoding (after all, the whole point of Shift JIS was to use an 8-bit
encoding for the katakana syllabary to save space or bandwidth).

I think if anyone wants to use UTF-16 or UTF-32 for exchange of Python
programs, they probably already know how to convert them to UTF-8.  As
somebody already suggested, this can be delegated to the py.exe
launcher, if necessary, AFAICS.

I don't see any good reason for allowing non-ASCII-compatible
encodings in the reference CPython interpreter.

However, having mentioned Windows and Java, I have to wonder about
IronPython and Jython, respectively.  Having never lived in either of
those environments, I don't know what text encoding their users might
prefer (or even occasionally encounter) in Python program source.

Steve

Footnotes: 
[1]  The version of Outlook Express shipped with them would emit
"HTML" mail with ASCII tags and UTF-8-encoded text (even if it was
encodable in pure ASCII).  No, it wasn't spam, either, so it probably
really was Outlook Express as it claimed to be in one of the headers.