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author | Karl Williamson <khw@khw-desktop.(none)> | 2010-04-24 11:03:48 -0600 |
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committer | Ricardo Signes <rjbs@cpan.org> | 2011-01-03 18:22:01 -0500 |
commit | 3ee86dd03f03c059828cf92e99ba0ea051639bf6 (patch) | |
tree | 61dacfe7588a05a66f178490a938c94d138711c4 | |
parent | 82b9aff1a79d033b4b652e6b36131a40d460fe12 (diff) | |
download | perl-3ee86dd03f03c059828cf92e99ba0ea051639bf6.tar.gz |
Nits in perluniintro.pod
Make accurate the advice about eighth-bit set characters, and a few
editing improvements.
-rw-r--r-- | pod/perluniintro.pod | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/pod/perluniintro.pod b/pod/perluniintro.pod index 6c82efde15..bee286f5ea 100644 --- a/pod/perluniintro.pod +++ b/pod/perluniintro.pod @@ -553,19 +553,19 @@ L<http://www.unicode.org/unicode/reports/tr10/> Character Ranges and Classes -Character ranges in regular expression character classes (C</[a-z]/>) -and in the C<tr///> (also known as C<y///>) operator are not magically -Unicode-aware. What this means is that C<[A-Za-z]> will not magically start -to mean "all alphabetic letters"; not that it does mean that even for -8-bit characters, you should be using C</[[:alpha:]]/> in that case. - -For specifying character classes like that in regular expressions, -you can use the various Unicode properties--C<\pL>, or perhaps -C<\p{Alphabetic}>, in this particular case. You can use Unicode -code points as the end points of character ranges, but there is no -magic associated with specifying a certain range. For further -information--there are dozens of Unicode character classes--see -L<perlunicode>. +Character ranges in regular expression bracketed character classes ( e.g., +C</[a-z]/>) and in the C<tr///> (also known as C<y///>) operator are not +magically Unicode-aware. What this means is that C<[A-Za-z]> will not +magically start to mean "all alphabetic letters" (not that it does mean that +even for 8-bit characters; for those, if you are using locales (L<perllocale>), +use C</[[:alpha:]]/>; and if not, use the 8-bit-aware property C<\p{alpha}>). + +All the properties that begin with C<\p> (and its inverse C<\P>) are actually +character classes that are Unicode-aware. There are dozens of them, see +L<perluniprops>. + +You can use Unicode code points as the end points of character ranges, and the +range will include all Unicode code points that lie between those end points. =item * @@ -607,7 +607,7 @@ Unicode; for that, see the earlier I/O discussion. How Do I Know Whether My String Is In Unicode? You shouldn't have to care. But you may, because currently the semantics of the -characters whose ordinals are in the range 128 to 255 is different depending on +characters whose ordinals are in the range 128 to 255 are different depending on whether the string they are contained within is in Unicode or not. (See L<perlunicode/When Unicode Does Not Happen>.) @@ -622,8 +622,8 @@ string has any characters at all. All the C<is_utf8()> does is to return the value of the internal "utf8ness" flag attached to the C<$string>. If the flag is off, the bytes in the scalar are interpreted as a single byte encoding. If the flag is on, the bytes in the scalar -are interpreted as the (multi-byte, variable-length) UTF-8 encoded code -points of the characters. Bytes added to a UTF-8 encoded string are +are interpreted as the (variable-length, potentially multi-byte) UTF-8 encoded +code points of the characters. Bytes added to a UTF-8 encoded string are automatically upgraded to UTF-8. If mixed non-UTF-8 and UTF-8 scalars are merged (double-quoted interpolation, explicit concatenation, and printf/sprintf parameter substitution), the result will be UTF-8 encoded @@ -648,6 +648,7 @@ the C<length()> function: use bytes; print length($unicode), "\n"; # will also print 2 # (the 0xC4 0x80 of the UTF-8) + no bytes; =item * |