Unicode::Collate(3pm) Perl Programmers Reference Guide Unicode::Collate(3pm)
NAME
Unicode::Collate - Unicode Collation Algorithm
SYNOPSIS
use Unicode::Collate;
#construct
$Collator = Unicode::Collate->new(%tailoring);
#sort
@sorted = $Collator->sort(@not_sorted);
#compare
$result = $Collator->cmp($a, $b); # returns 1, 0, or -1.
Note: Strings in @not_sorted, $a and $b are interpreted according to
Perl's Unicode support. See perlunicode, perluniintro, perlunitut,
perlunifaq, utf8. Otherwise you can use "preprocess" or should decode
them before.
DESCRIPTION
This module is an implementation of Unicode Technical Standard #10
(a.k.a. UTS #10) - Unicode Collation Algorithm (a.k.a. UCA).
Constructor and Tailoring
The "new" method returns a collator object. If new() is called with no
parameters, the collator should do the default collation.
$Collator = Unicode::Collate->new(
UCA_Version => $UCA_Version,
alternate => $alternate, # alias for 'variable'
backwards => $levelNumber, # or \@levelNumbers
entry => $element,
hangul_terminator => $term_primary_weight,
ignoreName => qr/$ignoreName/,
ignoreChar => qr/$ignoreChar/,
ignore_level2 => $bool,
katakana_before_hiragana => $bool,
level => $collationLevel,
normalization => $normalization_form,
overrideCJK => \&overrideCJK,
overrideHangul => \&overrideHangul,
preprocess => \&preprocess,
rearrange => \@charList,
rewrite => \&rewrite,
suppress => \@charList,
table => $filename,
undefName => qr/$undefName/,
undefChar => qr/$undefChar/,
upper_before_lower => $bool,
variable => $variable,
);
UCA_Version
If the revision (previously "tracking version") number of UCA is
given, behavior of that revision is emulated on collating. If
omitted, the return value of "UCA_Version()" is used.
The following revisions are supported. The default is 24.
UCA Unicode Standard DUCET (@version)
-------------------------------------------------------
8 3.1 3.0.1 (3.0.1d9)
9 3.1 with Corrigendum 3 3.1.1 (3.1.1)
11 4.0 4.0.0 (4.0.0)
14 4.1.0 4.1.0 (4.1.0)
16 5.0 5.0.0 (5.0.0)
18 5.1.0 5.1.0 (5.1.0)
20 5.2.0 5.2.0 (5.2.0)
22 6.0.0 6.0.0 (6.0.0)
24 6.1.0 6.1.0 (6.1.0)
* Noncharacters (e.g. U+FFFF) are not ignored, and can be
overridden since "UCA_Version" 22.
* Fully ignorable characters were ignored, and would not interrupt
contractions with "UCA_Version" 9 and 11.
* Treatment of ignorables after variables and some behaviors were
changed at "UCA_Version" 9.
* Characters regarded as CJK unified ideographs (cf. "overrideCJK")
depend on "UCA_Version".
* Many hangul jamo are assigned at "UCA_Version" 20, that will
affect "hangul_terminator".
alternate
-- see 3.2.2 Alternate Weighting, version 8 of UTS #10
For backward compatibility, "alternate" (old name) can be used as
an alias for "variable".
backwards
-- see 3.1.2 French Accents, UTS #10.
backwards => $levelNumber or \@levelNumbers
Weights in reverse order; ex. level 2 (diacritic ordering) in
French. If omitted (or $levelNumber is "undef" or "\@levelNumbers"
is "[]"), forwards at all the levels.
entry
-- see 3.1 Linguistic Features; 3.2.1 File Format, UTS #10.
If the same character (or a sequence of characters) exists in the
collation element table through "table", mapping to collation
elements is overridden. If it does not exist, the mapping is
defined additionally.
entry => <<'ENTRY', # for DUCET v4.0.0 (allkeys-4.0.0.txt)
0063 0068 ; [.0E6A.0020.0002.0063] # ch
0043 0068 ; [.0E6A.0020.0007.0043] # Ch
0043 0048 ; [.0E6A.0020.0008.0043] # CH
006C 006C ; [.0F4C.0020.0002.006C] # ll
004C 006C ; [.0F4C.0020.0007.004C] # Ll
004C 004C ; [.0F4C.0020.0008.004C] # LL
00F1 ; [.0F7B.0020.0002.00F1] # n-tilde
006E 0303 ; [.0F7B.0020.0002.00F1] # n-tilde
00D1 ; [.0F7B.0020.0008.00D1] # N-tilde
004E 0303 ; [.0F7B.0020.0008.00D1] # N-tilde
ENTRY
entry => <<'ENTRY', # for DUCET v4.0.0 (allkeys-4.0.0.txt)
00E6 ; [.0E33.0020.0002.00E6][.0E8B.0020.0002.00E6] # ae ligature as <a><e>
00C6 ; [.0E33.0020.0008.00C6][.0E8B.0020.0008.00C6] # AE ligature as <A><E>
ENTRY
NOTE: The code point in the UCA file format (before ';') must be a
Unicode code point (defined as hexadecimal), but not a native code
point. So 0063 must always denote "U+0063", but not a character of
"\x63".
Weighting may vary depending on collation element table. So ensure
the weights defined in "entry" will be consistent with those in the
collation element table loaded via "table".
In DUCET v4.0.0, primary weight of "C" is 0E60 and that of "D" is
"0E6D". So setting primary weight of "CH" to "0E6A" (as a value
between 0E60 and "0E6D") makes ordering as "C < CH < D". Exactly
speaking DUCET already has some characters between "C" and "D":
"small capital C" ("U+1D04") with primary weight 0E64,
"c-hook/C-hook" ("U+0188/U+0187") with 0E65, and "c-curl"
("U+0255") with 0E69. Then primary weight "0E6A" for "CH" makes
"CH" ordered between "c-curl" and "D".
hangul_terminator
-- see 7.1.4 Trailing Weights, UTS #10.
If a true value is given (non-zero but should be positive), it will
be added as a terminator primary weight to the end of every
standard Hangul syllable. Secondary and any higher weights for
terminator are set to zero. If the value is false or
"hangul_terminator" key does not exist, insertion of terminator
weights will not be performed.
Boundaries of Hangul syllables are determined according to
conjoining Jamo behavior in the Unicode Standard and
HangulSyllableType.txt.
Implementation Note: (1) For expansion mapping (Unicode character
mapped to a sequence of collation elements), a terminator will not
be added between collation elements, even if Hangul syllable
boundary exists there. Addition of terminator is restricted to the
next position to the last collation element.
(2) Non-conjoining Hangul letters (Compatibility Jamo, halfwidth
Jamo, and enclosed letters) are not automatically terminated with a
terminator primary weight. These characters may need terminator
included in a collation element table beforehand.
ignoreChar
ignoreName
-- see 3.2.2 Variable Weighting, UTS #10.
Makes the entry in the table completely ignorable; i.e. as if the
weights were zero at all level.
Through "ignoreChar", any character matching "qr/$ignoreChar/" will
be ignored. Through "ignoreName", any character whose name (given
in the "table" file as a comment) matches "qr/$ignoreName/" will be
ignored.
E.g. when 'a' and 'e' are ignorable, 'element' is equal to 'lament'
(or 'lmnt').
ignore_level2
-- see 5.1 Parametric Tailoring, UTS #10.
By default, case-sensitive comparison (that is level 3 difference)
won't ignore accents (that is level 2 difference).
If the parameter is made true, accents (and other primary ignorable
characters) are ignored, even though cases are taken into account.
NOTE: "level" should be 3 or greater.
katakana_before_hiragana
-- see 7.3.1 Tertiary Weight Table, UTS #10.
By default, hiragana is before katakana. If the parameter is made
true, this is reversed.
NOTE: This parameter simplemindedly assumes that any
hiragana/katakana distinctions must occur in level 3, and their
weights at level 3 must be same as those mentioned in 7.3.1, UTS
#10. If you define your collation elements which violate this
requirement, this parameter does not work validly.
level
-- see 4.3 Form Sort Key, UTS #10.
Set the maximum level. Any higher levels than the specified one
are ignored.
Level 1: alphabetic ordering
Level 2: diacritic ordering
Level 3: case ordering
Level 4: tie-breaking (e.g. in the case when variable is 'shifted')
ex.level => 2,
If omitted, the maximum is the 4th.
normalization
-- see 4.1 Normalize, UTS #10.
If specified, strings are normalized before preparation of sort
keys (the normalization is executed after preprocess).
A form name "Unicode::Normalize::normalize()" accepts will be
applied as $normalization_form. Acceptable names include 'NFD',
'NFC', 'NFKD', and 'NFKC'. See "Unicode::Normalize::normalize()"
for detail. If omitted, 'NFD' is used.
"normalization" is performed after "preprocess" (if defined).
Furthermore, special values, "undef" and "prenormalized", can be
used, though they are not concerned with
"Unicode::Normalize::normalize()".
If "undef" (not a string "undef") is passed explicitly as the value
for this key, any normalization is not carried out (this may make
tailoring easier if any normalization is not desired). Under
"(normalization => undef)", only contiguous contractions are
resolved; e.g. even if "A-ring" (and "A-ring-cedilla") is ordered
after "Z", "A-cedilla-ring" would be primary equal to "A". In this
point, "(normalization => undef, preprocess => sub { NFD(shift) })"
is not equivalent to "(normalization => 'NFD')".
In the case of "(normalization => "prenormalized")", any
normalization is not performed, but discontiguous contractions with
combining characters are performed. Therefore "(normalization =>
'prenormalized', preprocess => sub { NFD(shift) })" is equivalent
to "(normalization => 'NFD')". If source strings are finely
prenormalized, "(normalization => 'prenormalized')" may save time
for normalization.
Except "(normalization => undef)", Unicode::Normalize is required
(see also CAVEAT).
overrideCJK
-- see 7.1 Derived Collation Elements, UTS #10.
By default, CJK unified ideographs are ordered in Unicode codepoint
order, but those in the CJK Unified Ideographs block are lesser
than those in the CJK Unified Ideographs Extension A etc.
In the CJK Unified Ideographs block:
U+4E00..U+9FA5 if UCA_Version is 8, 9 or 11.
U+4E00..U+9FBB if UCA_Version is 14 or 16.
U+4E00..U+9FC3 if UCA_Version is 18.
U+4E00..U+9FCB if UCA_Version is 20 or 22.
U+4E00..U+9FCC if UCA_Version is 24.
In the CJK Unified Ideographs Extension blocks:
Ext.A (U+3400..U+4DB5) and Ext.B (U+20000..U+2A6D6) in any UCA_Version.
Ext.C (U+2A700..U+2B734) if UCA_Version is 20 or greater.
Ext.D (U+2B740..U+2B81D) if UCA_Version is 22 or greater.
Through "overrideCJK", ordering of CJK unified ideographs
(including extensions) can be overridden.
ex. CJK unified ideographs in the JIS code point order.
overrideCJK => sub {
my $u = shift; # get a Unicode codepoint
my $b = pack('n', $u); # to UTF-16BE
my $s = your_unicode_to_sjis_converter($b); # convert
my $n = unpack('n', $s); # convert sjis to short
[ $n, 0x20, 0x2, $u ]; # return the collation element
},
The return value may be an arrayref of 1st to 4th weights as shown
above. The return value may be an integer as the primary weight as
shown below. If "undef" is returned, the default derived collation
element will be used.
overrideCJK => sub {
my $u = shift; # get a Unicode codepoint
my $b = pack('n', $u); # to UTF-16BE
my $s = your_unicode_to_sjis_converter($b); # convert
my $n = unpack('n', $s); # convert sjis to short
return $n; # return the primary weight
},
The return value may be a list containing zero or more of an
arrayref, an integer, or "undef".
ex. ignores all CJK unified ideographs.
overrideCJK => sub {()}, # CODEREF returning empty list
# where ->eq("Pe\x{4E00}rl", "Perl") is true
# as U+4E00 is a CJK unified ideograph and to be ignorable.
If "undef" is passed explicitly as the value for this key, weights
for CJK unified ideographs are treated as undefined. But
assignment of weight for CJK unified ideographs in "table" or
"entry" is still valid.
Note: In addition to them, 12 CJK compatibility ideographs
("U+FA0E", "U+FA0F", "U+FA11", "U+FA13", "U+FA14", "U+FA1F",
"U+FA21", "U+FA23", "U+FA24", "U+FA27", "U+FA28", "U+FA29") are
also treated as CJK unified ideographs. But they can't be
overridden via "overrideCJK" when you use DUCET, as the table
includes weights for them. "table" or "entry" has priority over
"overrideCJK".
overrideHangul
-- see 7.1 Derived Collation Elements, UTS #10.
By default, Hangul syllables are decomposed into Hangul Jamo, even
if "(normalization => undef)". But the mapping of Hangul syllables
may be overridden.
This parameter works like "overrideCJK", so see there for examples.
If you want to override the mapping of Hangul syllables, NFD and
NFKD are not appropriate, since NFD and NFKD will decompose Hangul
syllables before overriding. FCD may decompose Hangul syllables as
the case may be.
If "undef" is passed explicitly as the value for this key, weight
for Hangul syllables is treated as undefined without decomposition
into Hangul Jamo. But definition of weight for Hangul syllables in
"table" or "entry" is still valid.
preprocess
-- see 5.1 Preprocessing, UTS #10.
If specified, the coderef is used to preprocess each string before
the formation of sort keys.
ex. dropping English articles, such as "a" or "the". Then, "the
pen" is before "a pencil".
preprocess => sub {
my $str = shift;
$str =~ s/\b(?:an?|the)\s+//gi;
return $str;
},
"preprocess" is performed before "normalization" (if defined).
ex. decoding strings in a legacy encoding such as shift-jis:
$sjis_collator = Unicode::Collate->new(
preprocess => \&your_shiftjis_to_unicode_decoder,
);
@result = $sjis_collator->sort(@shiftjis_strings);
Note: Strings returned from the coderef will be interpreted
according to Perl's Unicode support. See perlunicode, perluniintro,
perlunitut, perlunifaq, utf8.
rearrange
-- see 3.1.3 Rearrangement, UTS #10.
Characters that are not coded in logical order and to be
rearranged. If "UCA_Version" is equal to or lesser than 11,
default is:
rearrange => [ 0x0E40..0x0E44, 0x0EC0..0x0EC4 ],
If you want to disallow any rearrangement, pass "undef" or "[]" (a
reference to empty list) as the value for this key.
If "UCA_Version" is equal to or greater than 14, default is "[]"
(i.e. no rearrangement).
According to the version 9 of UCA, this parameter shall not be
used; but it is not warned at present.
rewrite
If specified, the coderef is used to rewrite lines in "table" or
"entry". The coderef will get each line, and then should return a
rewritten line according to the UCA file format. If the coderef
returns an empty line, the line will be skipped.
e.g. any primary ignorable characters into tertiary ignorable:
rewrite => sub {
my $line = shift;
$line =~ s/\[\.0000\..{4}\..{4}\./[.0000.0000.0000./g;
return $line;
},
This example shows rewriting weights. "rewrite" is allowed to
affect code points, weights, and the name.
NOTE: "table" is available to use another table file; preparing a
modified table once would be more efficient than rewriting lines on
reading an unmodified table every time.
suppress
-- see suppress contractions in 5.14.11 Special-Purpose Commands,
UTS #35 (LDML).
Contractions beginning with the specified characters are
suppressed, even if those contractions are defined in "table".
An example for Russian and some languages using the Cyrillic
script:
suppress => [0x0400..0x0417, 0x041A..0x0437, 0x043A..0x045F],
where 0x0400 stands for "U+0400", CYRILLIC CAPITAL LETTER IE WITH
GRAVE.
NOTE: Contractions via "entry" are not be suppressed.
table
-- see 3.2 Default Unicode Collation Element Table, UTS #10.
You can use another collation element table if desired.
The table file should locate in the Unicode/Collate directory on
@INC. Say, if the filename is Foo.txt, the table file is searched
as Unicode/Collate/Foo.txt in @INC.
By default, allkeys.txt (as the filename of DUCET) is used. If you
will prepare your own table file, any name other than allkeys.txt
may be better to avoid namespace conflict.
NOTE: When XSUB is used, the DUCET is compiled on building this
module, and it may save time at the run time. Explicit saying
"table => 'allkeys.txt'" (or using another table), or using
"ignoreChar", "ignoreName", "undefChar", "undefName" or "rewrite"
will prevent this module from using the compiled DUCET.
If "undef" is passed explicitly as the value for this key, no file
is read (but you can define collation elements via "entry").
A typical way to define a collation element table without any file
of table:
$onlyABC = Unicode::Collate->new(
table => undef,
entry => << 'ENTRIES',
0061 ; [.0101.0020.0002.0061] # LATIN SMALL LETTER A
0041 ; [.0101.0020.0008.0041] # LATIN CAPITAL LETTER A
0062 ; [.0102.0020.0002.0062] # LATIN SMALL LETTER B
0042 ; [.0102.0020.0008.0042] # LATIN CAPITAL LETTER B
0063 ; [.0103.0020.0002.0063] # LATIN SMALL LETTER C
0043 ; [.0103.0020.0008.0043] # LATIN CAPITAL LETTER C
ENTRIES
);
If "ignoreName" or "undefName" is used, character names should be
specified as a comment (following "#") on each line.
undefChar
undefName
-- see 6.3.4 Reducing the Repertoire, UTS #10.
Undefines the collation element as if it were unassigned in the
"table". This reduces the size of the table. If an unassigned
character appears in the string to be collated, the sort key is
made from its codepoint as a single-character collation element, as
it is greater than any other assigned collation elements (in the
codepoint order among the unassigned characters). But, it'd be
better to ignore characters unfamiliar to you and maybe never used.
Through "undefChar", any character matching "qr/$undefChar/" will
be undefined. Through "undefName", any character whose name (given
in the "table" file as a comment) matches "qr/$undefName/" will be
undefined.
ex. Collation weights for beyond-BMP characters are not stored in
object:
undefChar => qr/[^\0-\x{fffd}]/,
upper_before_lower
-- see 6.6 Case Comparisons, UTS #10.
By default, lowercase is before uppercase. If the parameter is
made true, this is reversed.
NOTE: This parameter simplemindedly assumes that any
lowercase/uppercase distinctions must occur in level 3, and their
weights at level 3 must be same as those mentioned in 7.3.1, UTS
#10. If you define your collation elements which differs from this
requirement, this parameter doesn't work validly.
variable
-- see 3.2.2 Variable Weighting, UTS #10.
This key allows for variable weighting of variable collation
elements, which are marked with an ASTERISK in the table (NOTE:
Many punctuation marks and symbols are variable in allkeys.txt).
variable => 'blanked', 'non-ignorable', 'shifted', or 'shift-trimmed'.
These names are case-insensitive. By default (if specification is
omitted), 'shifted' is adopted.
'Blanked' Variable elements are made ignorable at levels 1 through 3;
considered at the 4th level.
'Non-Ignorable' Variable elements are not reset to ignorable.
'Shifted' Variable elements are made ignorable at levels 1 through 3
their level 4 weight is replaced by the old level 1 weight.
Level 4 weight for Non-Variable elements is 0xFFFF.
'Shift-Trimmed' Same as 'shifted', but all FFFF's at the 4th level
are trimmed.
Methods for Collation
"@sorted = $Collator->sort(@not_sorted)"
Sorts a list of strings.
"$result = $Collator->cmp($a, $b)"
Returns 1 (when $a is greater than $b) or 0 (when $a is equal to
$b) or -1 (when $a is lesser than $b).
"$result = $Collator->eq($a, $b)"
"$result = $Collator->ne($a, $b)"
"$result = $Collator->lt($a, $b)"
"$result = $Collator->le($a, $b)"
"$result = $Collator->gt($a, $b)"
"$result = $Collator->ge($a, $b)"
They works like the same name operators as theirs.
eq : whether $a is equal to $b.
ne : whether $a is not equal to $b.
lt : whether $a is lesser than $b.
le : whether $a is lesser than $b or equal to $b.
gt : whether $a is greater than $b.
ge : whether $a is greater than $b or equal to $b.
"$sortKey = $Collator->getSortKey($string)"
-- see 4.3 Form Sort Key, UTS #10.
Returns a sort key.
You compare the sort keys using a binary comparison and get the
result of the comparison of the strings using UCA.
$Collator->getSortKey($a) cmp $Collator->getSortKey($b)
is equivalent to
$Collator->cmp($a, $b)
"$sortKeyForm = $Collator->viewSortKey($string)"
Converts a sorting key into its representation form. If
"UCA_Version" is 8, the output is slightly different.
use Unicode::Collate;
my $c = Unicode::Collate->new();
print $c->viewSortKey("Perl"),"\n";
# output:
# [0B67 0A65 0B7F 0B03 | 0020 0020 0020 0020 | 0008 0002 0002 0002 | FFFF FFFF FFFF FFFF]
# Level 1 Level 2 Level 3 Level 4
Methods for Searching
The "match", "gmatch", "subst", "gsubst" methods work like "m//",
"m//g", "s///", "s///g", respectively, but they are not aware of any
pattern, but only a literal substring.
DISCLAIMER: If "preprocess" or "normalization" parameter is true for
$Collator, calling these methods ("index", "match", "gmatch", "subst",
"gsubst") is croaked, as the position and the length might differ from
those on the specified string.
"rearrange" and "hangul_terminator" parameters are neglected.
"katakana_before_hiragana" and "upper_before_lower" don't affect
matching and searching, as it doesn't matter whether greater or lesser.
"$position = $Collator->index($string, $substring[, $position])"
"($position, $length) = $Collator->index($string, $substring[,
$position])"
If $substring matches a part of $string, returns the position of
the first occurrence of the matching part in scalar context; in
list context, returns a two-element list of the position and the
length of the matching part.
If $substring does not match any part of $string, returns "-1" in
scalar context and an empty list in list context.
e.g. you say
my $Collator = Unicode::Collate->new( normalization => undef, level => 1 );
# (normalization => undef) is REQUIRED.
my $str = "Ich muss studieren Perl.";
my $sub = "MUeSS";
my $match;
if (my($pos,$len) = $Collator->index($str, $sub)) {
$match = substr($str, $pos, $len);
}
and get "muss" in $match since "muss" is primary equal to "MUeSS".
"$match_ref = $Collator->match($string, $substring)"
"($match) = $Collator->match($string, $substring)"
If $substring matches a part of $string, in scalar context, returns
a reference to the first occurrence of the matching part
($match_ref is always true if matches, since every reference is
true); in list context, returns the first occurrence of the
matching part.
If $substring does not match any part of $string, returns "undef"
in scalar context and an empty list in list context.
e.g.
if ($match_ref = $Collator->match($str, $sub)) { # scalar context
print "matches [$$match_ref].\n";
} else {
print "doesn't match.\n";
}
or
if (($match) = $Collator->match($str, $sub)) { # list context
print "matches [$match].\n";
} else {
print "doesn't match.\n";
}
"@match = $Collator->gmatch($string, $substring)"
If $substring matches a part of $string, returns all the matching
parts (or matching count in scalar context).
If $substring does not match any part of $string, returns an empty
list.
"$count = $Collator->subst($string, $substring, $replacement)"
If $substring matches a part of $string, the first occurrence of
the matching part is replaced by $replacement ($string is modified)
and $count (always equals to 1) is returned.
$replacement can be a "CODEREF", taking the matching part as an
argument, and returning a string to replace the matching part (a
bit similar to "s/(..)/$coderef->($1)/e").
"$count = $Collator->gsubst($string, $substring, $replacement)"
If $substring matches a part of $string, all the occurrences of the
matching part are replaced by $replacement ($string is modified)
and $count is returned.
$replacement can be a "CODEREF", taking the matching part as an
argument, and returning a string to replace the matching part (a
bit similar to "s/(..)/$coderef->($1)/eg").
e.g.
my $Collator = Unicode::Collate->new( normalization => undef, level => 1 );
# (normalization => undef) is REQUIRED.
my $str = "Camel donkey zebra came\x{301}l CAMEL horse cam\0e\0l...";
$Collator->gsubst($str, "camel", sub { "<b>$_[0]</b>" });
# now $str is "<b>Camel</b> donkey zebra <b>came\x{301}l</b> <b>CAMEL</b> horse <b>cam\0e\0l</b>...";
# i.e., all the camels are made bold-faced.
Examples: levels and ignore_level2 - what does camel match?
---------------------------------------------------------------------------
level ignore_level2 | camel Camel came\x{301}l c-a-m-e-l cam\0e\0l
-----------------------|---------------------------------------------------
1 false | yes yes yes yes yes
2 false | yes yes no yes yes
3 false | yes no no yes yes
4 false | yes no no no yes
-----------------------|---------------------------------------------------
1 true | yes yes yes yes yes
2 true | yes yes yes yes yes
3 true | yes no yes yes yes
4 true | yes no yes no yes
---------------------------------------------------------------------------
note: if variable => non-ignorable, camel doesn't match c-a-m-e-l
at any level.
Other Methods
"%old_tailoring = $Collator->change(%new_tailoring)"
"$modified_collator = $Collator->change(%new_tailoring)"
Changes the value of specified keys and returns the changed part.
$Collator = Unicode::Collate->new(level => 4);
$Collator->eq("perl", "PERL"); # false
%old = $Collator->change(level => 2); # returns (level => 4).
$Collator->eq("perl", "PERL"); # true
$Collator->change(%old); # returns (level => 2).
$Collator->eq("perl", "PERL"); # false
Not all "(key,value)"s are allowed to be changed. See also
@Unicode::Collate::ChangeOK and @Unicode::Collate::ChangeNG.
In the scalar context, returns the modified collator (but it is not
a clone from the original).
$Collator->change(level => 2)->eq("perl", "PERL"); # true
$Collator->eq("perl", "PERL"); # true; now max level is 2nd.
$Collator->change(level => 4)->eq("perl", "PERL"); # false
"$version = $Collator->version()"
Returns the version number (a string) of the Unicode Standard which
the "table" file used by the collator object is based on. If the
table does not include a version line (starting with @version),
returns "unknown".
"UCA_Version()"
Returns the revision number of UTS #10 this module consults, that
should correspond with the DUCET incorporated.
"Base_Unicode_Version()"
Returns the version number of UTS #10 this module consults, that
should correspond with the DUCET incorporated.
EXPORT
No method will be exported.
INSTALL
Though this module can be used without any "table" file, to use this
module easily, it is recommended to install a table file in the UCA
format, by copying it under the directory <a place in
@INC>/Unicode/Collate.
The most preferable one is "The Default Unicode Collation Element
Table" (aka DUCET), available from the Unicode Consortium's website:
http://www.unicode.org/Public/UCA/
http://www.unicode.org/Public/UCA/latest/allkeys.txt (latest version)
If DUCET is not installed, it is recommended to copy the file from
http://www.unicode.org/Public/UCA/latest/allkeys.txt to <a place in
@INC>/Unicode/Collate/allkeys.txt manually.
CAVEATS
Normalization
Use of the "normalization" parameter requires the
Unicode::Normalize module (see Unicode::Normalize).
If you need not it (say, in the case when you need not handle any
combining characters), assign "normalization => undef" explicitly.
-- see 6.5 Avoiding Normalization, UTS #10.
Conformance Test
The Conformance Test for the UCA is available under
<http://www.unicode.org/Public/UCA/>;.
For CollationTest_SHIFTED.txt, a collator via
"Unicode::Collate->new( )" should be used; for
CollationTest_NON_IGNORABLE.txt, a collator via
"Unicode::Collate->new(variable => "non-ignorable", level => 3)".
Unicode::Normalize is required to try The Conformance Test.
AUTHOR, COPYRIGHT AND LICENSE
The Unicode::Collate module for perl was written by SADAHIRO Tomoyuki,
<SADAHIRO AT cpan.org>. This module is Copyright(C) 2001-2012, SADAHIRO
Tomoyuki. Japan. All rights reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
The file Unicode/Collate/allkeys.txt was copied verbatim from
<http://www.unicode.org/Public/UCA/6.1.0/allkeys.txt>;. For this file,
Copyright (c) 2001-2011 Unicode, Inc. Distributed under the Terms of
Use in <http://www.unicode.org/copyright.html>;.
SEE ALSO
Unicode Collation Algorithm - UTS #10
<http://www.unicode.org/reports/tr10/>;
The Default Unicode Collation Element Table (DUCET)
<http://www.unicode.org/Public/UCA/latest/allkeys.txt>;
The conformance test for the UCA
<http://www.unicode.org/Public/UCA/latest/CollationTest.html>;
<http://www.unicode.org/Public/UCA/latest/CollationTest.zip>;
Hangul Syllable Type
<http://www.unicode.org/Public/UNIDATA/HangulSyllableType.txt>;
Unicode Normalization Forms - UAX #15
<http://www.unicode.org/reports/tr15/>;
Unicode Locale Data Markup Language (LDML) - UTS #35
<http://www.unicode.org/reports/tr35/>;
perl v5.16.3 2013-03-04 Unicode::Collate(3pm)
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