diff options
Diffstat (limited to 'upstream/mageia-cauldron/man3pm/utf8.3pm')
| -rw-r--r-- | upstream/mageia-cauldron/man3pm/utf8.3pm | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/upstream/mageia-cauldron/man3pm/utf8.3pm b/upstream/mageia-cauldron/man3pm/utf8.3pm new file mode 100644 index 00000000..2a399707 --- /dev/null +++ b/upstream/mageia-cauldron/man3pm/utf8.3pm @@ -0,0 +1,328 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'br\} +.\" +.\" Escape single quotes in literal strings from groff's Unicode transform. +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" +.\" If the F register is >0, we'll generate index entries on stderr for +.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index +.\" entries marked with X<> in POD. Of course, you'll have to process the +.\" output yourself in some meaningful fashion. +.\" +.\" Avoid warning from groff about undefined register 'F'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" ======================================================================== +.\" +.IX Title "utf8 3pm" +.TH utf8 3pm 2023-11-28 "perl v5.38.2" "Perl Programmers Reference Guide" +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH NAME +utf8 \- Perl pragma to enable/disable UTF\-8 (or UTF\-EBCDIC) in source code +.SH SYNOPSIS +.IX Header "SYNOPSIS" +.Vb 2 +\& use utf8; +\& no utf8; +\& +\& # Convert the internal representation of a Perl scalar to/from UTF\-8. +\& +\& $num_octets = utf8::upgrade($string); +\& $success = utf8::downgrade($string[, $fail_ok]); +\& +\& # Change each character of a Perl scalar to/from a series of +\& # characters that represent the UTF\-8 bytes of each original character. +\& +\& utf8::encode($string); # "\ex{100}" becomes "\exc4\ex80" +\& utf8::decode($string); # "\exc4\ex80" becomes "\ex{100}" +\& +\& # Convert a code point from the platform native character set to +\& # Unicode, and vice\-versa. +\& $unicode = utf8::native_to_unicode(ord(\*(AqA\*(Aq)); # returns 65 on both +\& # ASCII and EBCDIC +\& # platforms +\& $native = utf8::unicode_to_native(65); # returns 65 on ASCII +\& # platforms; 193 on +\& # EBCDIC +\& +\& $flag = utf8::is_utf8($string); # since Perl 5.8.1 +\& $flag = utf8::valid($string); +.Ve +.SH DESCRIPTION +.IX Header "DESCRIPTION" +The \f(CW\*(C`use utf8\*(C'\fR pragma tells the Perl parser to allow UTF\-8 in the +program text in the current lexical scope. The \f(CW\*(C`no utf8\*(C'\fR pragma tells Perl +to switch back to treating the source text as literal bytes in the current +lexical scope. (On EBCDIC platforms, technically it is allowing UTF-EBCDIC, +and not UTF\-8, but this distinction is academic, so in this document the term +UTF\-8 is used to mean both). +.PP +\&\fBDo not use this pragma for anything else than telling Perl that your +script is written in UTF\-8.\fR The utility functions described below are +directly usable without \f(CW\*(C`use utf8;\*(C'\fR. +.PP +Because it is not possible to reliably tell UTF\-8 from native 8 bit +encodings, you need either a Byte Order Mark at the beginning of your +source code, or \f(CW\*(C`use utf8;\*(C'\fR, to instruct perl. +.PP +When UTF\-8 becomes the standard source format, this pragma will +effectively become a no-op. +.PP +See also the effects of the \f(CW\*(C`\-C\*(C'\fR switch and its cousin, the +\&\f(CW\*(C`PERL_UNICODE\*(C'\fR environment variable, in perlrun. +.PP +Enabling the \f(CW\*(C`utf8\*(C'\fR pragma has the following effect: +.IP \(bu 4 +Bytes in the source text that are not in the ASCII character set will be +treated as being part of a literal UTF\-8 sequence. This includes most +literals such as identifier names, string constants, and constant +regular expression patterns. +.PP +Note that if you have non-ASCII, non\-UTF\-8 bytes in your script (for example +embedded Latin\-1 in your string literals), \f(CW\*(C`use utf8\*(C'\fR will be unhappy. If +you want to have such bytes under \f(CW\*(C`use utf8\*(C'\fR, you can disable this pragma +until the end the block (or file, if at top level) by \f(CW\*(C`no utf8;\*(C'\fR. +.SS "Utility functions" +.IX Subsection "Utility functions" +The following functions are defined in the \f(CW\*(C`utf8::\*(C'\fR package by the +Perl core. You do not need to say \f(CW\*(C`use utf8\*(C'\fR to use these and in fact +you should not say that unless you really want to have UTF\-8 source code. +.IP \(bu 4 +\&\f(CW\*(C`$num_octets = utf8::upgrade($string)\*(C'\fR +.Sp +(Since Perl v5.8.0) +Converts in-place the internal representation of the string from an octet +sequence in the native encoding (Latin\-1 or EBCDIC) to UTF\-8. The +logical character sequence itself is unchanged. If \fR\f(CI$string\fR\fI\fR is already +upgraded, then this is a no-op. Returns the +number of octets necessary to represent the string as UTF\-8. +Since Perl v5.38, if \f(CW$string\fR is \f(CW\*(C`undef\*(C'\fR no action is taken; prior to that, +it would be converted to be defined and zero-length. +.Sp +If your code needs to be compatible with versions of perl without +\&\f(CW\*(C`use feature \*(Aqunicode_strings\*(Aq;\*(C'\fR, you can force Unicode semantics on +a given string: +.Sp +.Vb 3 +\& # force unicode semantics for $string without the +\& # "unicode_strings" feature +\& utf8::upgrade($string); +.Ve +.Sp +For example: +.Sp +.Vb 7 +\& # without explicit or implicit use feature \*(Aqunicode_strings\*(Aq +\& my $x = "\exDF"; # LATIN SMALL LETTER SHARP S +\& $x =~ /ss/i; # won\*(Aqt match +\& my $y = uc($x); # won\*(Aqt convert +\& utf8::upgrade($x); +\& $x =~ /ss/i; # matches +\& my $z = uc($x); # converts to "SS" +.Ve +.Sp +\&\fBNote that this function does not handle arbitrary encodings\fR; +use Encode instead. +.IP \(bu 4 +\&\f(CW\*(C`$success = utf8::downgrade($string[, $fail_ok])\*(C'\fR +.Sp +(Since Perl v5.8.0) +Converts in-place the internal representation of the string from UTF\-8 to the +equivalent octet sequence in the native encoding (Latin\-1 or EBCDIC). The +logical character sequence itself is unchanged. If \fR\f(CI$string\fR\fI\fR is already +stored as native 8 bit, then this is a no-op. Can be used to make sure that +the UTF\-8 flag is off, e.g. when you want to make sure that the \fBsubstr()\fR or +\&\fBlength()\fR function works with the usually faster byte algorithm. +.Sp +Fails if the original UTF\-8 sequence cannot be represented in the +native 8 bit encoding. On failure dies or, if the value of \fR\f(CI$fail_ok\fR\fI\fR is +true, returns false. +.Sp +Returns true on success. +.Sp +If your code expects an octet sequence this can be used to validate +that you've received one: +.Sp +.Vb 2 +\& # throw an exception if not representable as octets +\& utf8::downgrade($string) +\& +\& # or do your own error handling +\& utf8::downgrade($string, 1) or die "string must be octets"; +.Ve +.Sp +\&\fBNote that this function does not handle arbitrary encodings\fR; +use Encode instead. +.IP \(bu 4 +\&\f(CWutf8::encode($string)\fR +.Sp +(Since Perl v5.8.0) +Converts in-place the character sequence to the corresponding octet +sequence in Perl's extended UTF\-8. That is, every (possibly wide) character +gets replaced with a sequence of one or more characters that represent the +individual UTF\-8 bytes of the character. The UTF8 flag is turned off. +Returns nothing. +.Sp +.Vb 4 +\& my $x = "\ex{100}"; # $x contains one character, with ord 0x100 +\& utf8::encode($x); # $x contains two characters, with ords (on +\& # ASCII platforms) 0xc4 and 0x80. On EBCDIC +\& # 1047, this would instead be 0x8C and 0x41. +.Ve +.Sp +Similar to: +.Sp +.Vb 2 +\& use Encode; +\& $x = Encode::encode("utf8", $x); +.Ve +.Sp +\&\fBNote that this function does not handle arbitrary encodings\fR; +use Encode instead. +.IP \(bu 4 +\&\f(CW\*(C`$success = utf8::decode($string)\*(C'\fR +.Sp +(Since Perl v5.8.0) +Attempts to convert in-place the octet sequence encoded in Perl's extended +UTF\-8 to the corresponding character sequence. That is, it replaces each +sequence of characters in the string whose ords represent a valid (extended) +UTF\-8 byte sequence, with the corresponding single character. The UTF\-8 flag +is turned on only if the source string contains multiple-byte UTF\-8 +characters. If \fR\f(CI$string\fR\fI\fR is invalid as extended UTF\-8, returns false; +otherwise returns true. +.Sp +.Vb 11 +\& my $x = "\exc4\ex80"; # $x contains two characters, with ords +\& # 0xc4 and 0x80 +\& utf8::decode($x); # On ASCII platforms, $x contains one char, +\& # with ord 0x100. Since these bytes aren\*(Aqt +\& # legal UTF\-EBCDIC, on EBCDIC platforms, $x is +\& # unchanged and the function returns FALSE. +\& my $y = "\exc3\ex83\exc2\exab"; This has been encoded twice; this +\& # example is only for ASCII platforms +\& utf8::decode($y); # Converts $y to \exc3\exab, returns TRUE; +\& utf8::decode($y); # Further converts to \exeb, returns TRUE; +\& utf8::decode($y); # Returns FALSE, leaves $y unchanged +.Ve +.Sp +\&\fBNote that this function does not handle arbitrary encodings\fR; +use Encode instead. +.IP \(bu 4 +\&\f(CW\*(C`$unicode = utf8::native_to_unicode($code_point)\*(C'\fR +.Sp +(Since Perl v5.8.0) +This takes an unsigned integer (which represents the ordinal number of a +character (or a code point) on the platform the program is being run on) and +returns its Unicode equivalent value. Since ASCII platforms natively use the +Unicode code points, this function returns its input on them. On EBCDIC +platforms it converts from EBCDIC to Unicode. +.Sp +A meaningless value will currently be returned if the input is not an unsigned +integer. +.Sp +Since Perl v5.22.0, calls to this function are optimized out on ASCII +platforms, so there is no performance hit in using it there. +.IP \(bu 4 +\&\f(CW\*(C`$native = utf8::unicode_to_native($code_point)\*(C'\fR +.Sp +(Since Perl v5.8.0) +This is the inverse of \f(CWutf8::native_to_unicode()\fR, converting the other +direction. Again, on ASCII platforms, this returns its input, but on EBCDIC +platforms it will find the native platform code point, given any Unicode one. +.Sp +A meaningless value will currently be returned if the input is not an unsigned +integer. +.Sp +Since Perl v5.22.0, calls to this function are optimized out on ASCII +platforms, so there is no performance hit in using it there. +.IP \(bu 4 +\&\f(CW\*(C`$flag = utf8::is_utf8($string)\*(C'\fR +.Sp +(Since Perl 5.8.1) Test whether \fR\f(CI$string\fR\fI\fR is marked internally as encoded in +UTF\-8. Functionally the same as \f(CWEncode::is_utf8($string)\fR. +.Sp +Typically only necessary for debugging and testing, if you need to +dump the internals of an SV, Devel::Peek's \fBDump()\fR +provides more detail in a compact form. +.Sp +If you still think you need this outside of debugging, testing or +dealing with filenames, you should probably read perlunitut and +"What is "the UTF8 flag"?" in perlunifaq. +.Sp +Don't use this flag as a marker to distinguish character and binary +data: that should be decided for each variable when you write your +code. +.Sp +To force unicode semantics in code portable to perl 5.8 and 5.10, call +\&\f(CWutf8::upgrade($string)\fR unconditionally. +.IP \(bu 4 +\&\f(CW\*(C`$flag = utf8::valid($string)\*(C'\fR +.Sp +[INTERNAL] Test whether \fR\f(CI$string\fR\fI\fR is in a consistent state regarding +UTF\-8. Will return true if it is well-formed Perl extended UTF\-8 and has the +UTF\-8 flag +on \fBor\fR if \fI\fR\f(CI$string\fR\fI\fR is held as bytes (both these states are 'consistent'). +The main reason for this routine is to allow Perl's test suite to check +that operations have left strings in a consistent state. +.PP +\&\f(CW\*(C`utf8::encode\*(C'\fR is like \f(CW\*(C`utf8::upgrade\*(C'\fR, but the UTF8 flag is +cleared. See perlunicode, and the C API +functions \f(CW\*(C`sv_utf8_upgrade\*(C'\fR, +\&\f(CW\*(C`"sv_utf8_downgrade" in perlapi\*(C'\fR, \f(CW\*(C`"sv_utf8_encode" in perlapi\*(C'\fR, +and \f(CW\*(C`"sv_utf8_decode" in perlapi\*(C'\fR, which are wrapped by the Perl functions +\&\f(CW\*(C`utf8::upgrade\*(C'\fR, \f(CW\*(C`utf8::downgrade\*(C'\fR, \f(CW\*(C`utf8::encode\*(C'\fR and +\&\f(CW\*(C`utf8::decode\*(C'\fR. Also, the functions \f(CW\*(C`utf8::is_utf8\*(C'\fR, \f(CW\*(C`utf8::valid\*(C'\fR, +\&\f(CW\*(C`utf8::encode\*(C'\fR, \f(CW\*(C`utf8::decode\*(C'\fR, \f(CW\*(C`utf8::upgrade\*(C'\fR, and \f(CW\*(C`utf8::downgrade\*(C'\fR are +actually internal, and thus always available, without a \f(CW\*(C`require utf8\*(C'\fR +statement. +.SH BUGS +.IX Header "BUGS" +Some filesystems may not support UTF\-8 file names, or they may be supported +incompatibly with Perl. Therefore UTF\-8 names that are visible to the +filesystem, such as module names may not work. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +perlunitut, perluniintro, perlrun, bytes, perlunicode |