| msg55314 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) *  |
Date: 2007-08-26 22:04 |
| io.StrinIO.getvalue() correctly decodes bytes from the underlying buffer, but does not translate \r\n to \n. Python 3.0x (py3k, Aug 26 2007, 14:39:16) [MSC v.1400 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import io >>> a = io.StringIO() >>> a.write('\n') 2 >>> a.getvalue() '\r\n' The attached patch corrects this and adds a test. |
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| msg55323 - (view) |
Author: Alexandre Vassalotti (alexandre.vassalotti) * |
Date: 2007-08-26 23:26 |
| As far as I know, StringIO should not do any string transformations. From PEP-3116 "New I/O", last paragraph of the section "Text I/O": > Another implementation, StringIO, creates a file-like TextIO > implementation without an underlying Buffered I/O object. [...] It > does not support encodings or newline translations; you always read > back exactly the characters you wrote. |
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| msg55324 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2007-08-26 23:35 |
| > As far as I know, StringIO should not do any string transformations. (Not sure if you agree with the patch or not) That's why the current behaviour is not correct: When I write('\n'), getvalue() currently returns '\r\n'. |
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| msg55341 - (view) |
Author: Alexandre Vassalotti (alexandre.vassalotti) * |
Date: 2007-08-27 22:38 |
| > That's why the current behaviour is not correct: When I write('\n'), > getvalue() currently returns '\r\n'. Oh, I missed your example in your initial message. So yes, I agree that StringIO shouldn't translate newlines like that. I attached a patch that should fix the bug. However, I would favor removing the "newline" keyword argument, instead. |
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| msg55359 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2007-08-28 09:00 |
| Here is a new version of the class, which removes the 'newline' argument from the constructor. I also removed the 'encoding' argument, since this is really an implementation detail of the underlying buffer. Index: Lib/io.py =================================================================== --- Lib/io.py (revision 57564) +++ Lib/io.py (working copy) @@ -1390,10 +1390,10 @@ # XXX This is really slow, but fully functional - def __init__(self, initial_value="", encoding="utf-8", newline=None): + def __init__(self, initial_value=""): super(StringIO, self).__init__(BytesIO(), - encoding=encoding, - newline=newline) + encoding="utf-8", + newline='\n') if initial_value: if not isinstance(initial_value, basestring): initial_value = str(initial_value) |
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| msg55428 - (view) |
Author: Guido van Rossum (gvanrossum) * |
Date: 2007-08-29 18:32 |
| I'ev fixed this slightly differently, by simply changing the *default* of the newline argument to StringIO to be "\n". This is a good default; but I see no reason to prevent users from messing with it if they have a need. |
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