En Sun, 22 Mar 2009 21:03:38 -0300, Scott David Daniels
<scott.dani...@acm.org> escribió:
Gabriel Genellina wrote:
En Sun, 22 Mar 2009 19:12:13 -0300, Benjamin Peterson
<benja...@python.org> escribió:
Gabriel Genellina <gagsl-py2 <at> yahoo.com.ar> writes:
The undocumented behavior is relying on the open() builtin to return a
BufferedReader for a binary file.
I don't see the problem. open() will return some BufferedIOBase
implmentor, and
that's all that TextIOWrapper needs.
How do you know? AFAIK, the return value of open() is completely
undocumented:
http://docs.python.org/3.0/library/functions.html#open
And if you open the file in text mode, the return value isn't a
BufferedIOBase.
OK, it is documented, but not so clearly. I went first to the io
module, rather than the open function documentation, and looked at
what io.TextIOWrapper should get ast its first arg:
[...]
The type of file object returned by the open() function depends on
the mode. When open() is used to open a file in a text mode ('w',
'r', 'wt', 'rt', etc.), it returns a TextIOWrapper. When used to
open a file in a binary mode, the returned class varies: in read
binary mode, it returns a BufferedReader; in write binary and append
binary modes, it returns a BufferedWriter, and in read/write mode,
it returns a BufferedRandom.
Aha! it is documented. If you have some good ideas on how to make
this more obvious, I'm sure we'd be happy to "fix" the documentation.
Ah, yes. Hmm, so the same description appears in three places: the open()
docstring, the docs for the builtin functions, and the docs for the io
module. And all three are different :(
Perhaps open.__doc__ == documentation for io.open, and documentation for
builtin.open should just tell the basic things and refer to io.open for
details...
--
Gabriel Genellina
--
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