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| author | Yitzchak Scott-Thoennes <sthoenna@efn.org> | 2000-11-10 01:47:15 -0800 |
|---|---|---|
| committer | Jarkko Hietaniemi <jhi@iki.fi> | 2000-11-13 04:05:07 +0000 |
| commit | a1ca4561f20dbf547f57d39a690790cbe33210da (patch) | |
| tree | 83f9af82cb7a2699ca5ca248e9907ac52b3924a8 /pod/perlunicode.pod | |
| parent | d26ab924bbea5dd5379307deb59c11af3692350b (diff) | |
| download | perl-a1ca4561f20dbf547f57d39a690790cbe33210da.tar.gz | |
Tweak the definition of the bit complement on UTF-8 data:
if none of the characters in the string are > 0xff,
the result is a complemented byte string, not a (UTF-8)
char string. Based on the summary in
Subject: Re: [ID 20000918.005] ~ on wide chars
Message-ID: <jSDD6gzkgi/T092yn@efn.org>
This should give us the maximum backward (pre-char string)
compatibility and utf8 compatibility. The other alternative
would be to limit the bit complement to be always byte only,
taking the least significant byte of the chars.
p4raw-id: //depot/perl@7665
Diffstat (limited to 'pod/perlunicode.pod')
| -rw-r--r-- | pod/perlunicode.pod | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/pod/perlunicode.pod b/pod/perlunicode.pod index e567e183e1..30a4482260 100644 --- a/pod/perlunicode.pod +++ b/pod/perlunicode.pod @@ -198,6 +198,18 @@ byte-oriented C<chr()> and C<ord()> under utf8. =item * +The bit string operators C<& | ^ ~> can operate on character data. +However, for backward compatibility reasons (bit string operations +when the characters all are less than 256 in ordinal value) one cannot +mix C<~> (the bit complement) and characters both less than 256 and +equal or greater than 256. Most importantly, the DeMorgan's laws +(C<~($x|$y) eq ~$x&~$y>, C<~($x&$y) eq ~$x|~$y>) won't hold. +Another way to look at this is that the complement cannot return +B<both> the 8-bit (byte) wide bit complement, and the full character +wide bit complement. + +=item * + And finally, C<scalar reverse()> reverses by character rather than by byte. =back |