[issue3359] add 'rbU' mode to open()

[Skip Montanaro]

Skip Montanaro <skip at pobox.com> added the comment:

anatoly> If you open file with 'r' - all line endings will be mapped
    anatoly> precisely to '\n' anyways, so it has nothing to do with 'U'
    anatoly> mode.

Before 3.0 at least, if you copy a text file from, say, Windows to Mac, and
open it with 'r', you get lines which end in '\r\n'.  Here's a simple
example:

    >>> open("dos.txt", "rb").read()
    'a single line\r\nanother line\r\n'
    >>> f = open("dos.txt")
    >>> f.next()
    'a single line\r\n'
    >>> f = open("dos.txt", "r")
    >>> f.next()
    'a single line\r\n'
    >>> f.next()
    'another line\r\n'

If, on the other hand, you open it with 'rU', the '\r\n' literal line ending
is converted, even though CRLF is not the canonical Mac line ending:

    >>> f = open("dos.txt", "rU")
    >>> f.next()
    'a single line\n'
    >>> f.next()
    'another line\n'

Skip

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue3359>
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