[ruby-dev:49663] [Ruby trunk Bug#11859][Rejected] Regexp matching with \p{Upper} and \p{Lower} for EUC-JP doesn’t work.

Issue #11859 has been updated by Yui NARUSE.

Status changed from Open to Rejected

Ruby doesn't have case tables for non Unicode encodings.

And EUC-JP is legacy encoding, I don't think such encoding should be extended.

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Bug #11859: Regexp matching with \p{Upper} and \p{Lower} for EUC-JP doesn’t work.
https://bugs.ruby-lang.org/issues/11859#change-59185

* Author: Kimihito Matsui
* Status: Rejected
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-darwin14]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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U+FF21 (Ａ, FULLWIDTH LATIN CAPITAL LETTER A) and U+00c0 (À, LATIN CAPITAL LETTER A WITH GRAVE) is `Uppercase_Letter` so it should match and return 0 in following case but this returns 1.

~~~
ruby -e 'puts "\uFF21A".encode("EUC-JP") =~ Regexp.compile("\\\p{Upper}".encode("EUC-JP”))' # => 1
ruby -e 'puts "\u00C0A".encode("EUC-JP") =~ Regexp.compile("\\\p{Upper}".encode("EUC-JP"))’ # => 1
~~~
This also happens in lower case matching.

~~~
ruby -e 'puts "\uFF41a".encode("EUC-JP") =~ Regexp.compile("\\\p{Lower}".encode("EUC-JP"))’ ＃=> 1
~~~

In Unicode encoding it works as follows.

~~~
ruby -e 'puts "\uFF21A" =~ Regexp.compile("\\\p{Upper}")'  # => 0
~~~
Looks like EUC-JP `\p{Upper}` and `\p{Lower}` regex is limited to ASCII characters.



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