Author ezio.melotti
Recipients ezio.melotti, giampaolo.rodola, loewis, vstinner
Date 2009-01-31.03:35:34
SpamBayes Score 5.60663e-15
Marked as misclassified No
Message-id <1233372939.78.0.388755298097.issue5110@psf.upfronthosting.co.za>
In-reply-to
Content
This seems to fix the problem:
------------------------------
import sys
import builtins

def hook(message):
    if message is None:
        return
    builtins._ = message
    try:
        print(repr(message))
    except UnicodeEncodeError:
        print(ascii(message))

sys.displayhook = hook
------------------------------
Just to clarify:
* The current Py3 behavior works fine in UTF8 terminals
* It doesn't work on non-UTF8 terminals if they can't encode the chars
(they raise an error)
* It only affects the interactive interpreter
* This new patch escapes the chars instead of raise an error only on
non-UTF8 terminal and only when printed as ">>> foo" (without print())
and leaves the other behaviors unchanged
* This is related to Py3 only

Apparently the patch provided by Victor always escapes the non-ascii
chars. This new hook function prints the Unicode chars if possible and
escapes them if not. On a UTF8 terminal the behavior is unchanged, on a
non-UTF8 terminal all the chars that can not be encoded will now be escaped.

This only changes the behavior of ">>> foo", so it can not lead to
confusion ("It works in the interpreter but not in the script"). In a
script one can't write "foo" alone but "print(foo)" and the behavior of
"print(foo)" is the same in both the interpreter and the scripts (with
the patch applied):

>>> ['\u2620']
['\u2620']
>>> print(['\u2620'])
UnicodeEncodeError: 'charmap' codec can't encode character '\u2620' in
position 2: character maps to <undefined>

I think that the PEP3138 didn't consider this issue. Its purpose is to
have a better output (Unicode chars instead of escaped chars), but it
only works with UTF8 terminals, on non-UTF8 terminals the output is
worse (UnicodeEncodeError instead of escaped chars).

This is an improvement and I can't see any negative side-effect.

Attached there's a txt with more example, on Py2 and Py3, on
Windows(non-UTF8 terminal) and Linux (UTF8 terminal), with and without
my patch.
History
Date User Action Args
2009-01-31 03:35:40ezio.melottisetrecipients: + ezio.melotti, loewis, vstinner, giampaolo.rodola
2009-01-31 03:35:39ezio.melottisetmessageid: <1233372939.78.0.388755298097.issue5110@psf.upfronthosting.co.za>
2009-01-31 03:35:36ezio.melottilinkissue5110 messages
2009-01-31 03:35:36ezio.melotticreate