[issue31193] re.IGNORECASE strips combining character from lower case of LATIN CAPITAL LETTER I WITH DOT ABOVE

[Matthew Barnett]

Matthew Barnett added the comment:

The re module works with codepoints, it doesn't understand canonical equivalence.

For example, it doesn't recognise that "\N{LATIN CAPITAL LETTER E}\N{COMBINING ACUTE ACCENT}" is equivalent to "\N{LATIN CAPITAL LETTER E WITH ACUTE}".

This is true for Python in general, except for identifiers, which are normalised:

>>> "\N{LATIN CAPITAL LETTER E}\N{COMBINING ACUTE ACCENT}"
'É'
>>> É = 0
>>> "\N{LATIN CAPITAL LETTER E WITH ACUTE}"
'É'
>>> É
0

This also means that, say '.' will match only 1 _codepoint_.

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nosy: +mrabarnett

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue31193>
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