| Unicode::Collate - Unicode Collation Algorithm |
Unicode::Collate - Unicode Collation Algorithm
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 the perlunicode manpage,
the perluniintro manpage, the perlunitut manpage, the perlunifaq manpage, the utf8 manpage.
Otherwise you can use preprocess or should decode them before.
This module is an implementation of Unicode Technical Standard #10 (a.k.a. UTS #10) - Unicode Collation Algorithm (a.k.a. UCA).
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,
highestFFFF => $bool,
identical => $bool,
ignoreName => qr/$ignoreName/,
ignoreChar => qr/$ignoreChar/,
ignore_level2 => $bool,
katakana_before_hiragana => $bool,
level => $collationLevel,
long_contraction => $bool,
minimalFFFE => $bool,
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() is used.
The following revisions are supported. The default is 36.
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)
26 6.2.0 6.2.0 (6.2.0)
28 6.3.0 6.3.0 (6.3.0)
30 7.0.0 7.0.0 (7.0.0)
32 8.0.0 8.0.0 (8.0.0)
34 9.0.0 9.0.0 (9.0.0)
36 10.0.0 10.0.0(10.0.0)
* See below for long_contraction with UCA_Version 22 and 24.
* Noncharacters (e.g. U+FFFF) are not ignored, and can be overridden
since UCA_Version 22.
* Out-of-range codepoints (greater than U+10FFFF) 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.
For backward compatibility, alternate (old name) can be used
as an alias for variable.
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.
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.
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.
If the parameter is made true, U+FFFF has a highest primary weight.
When a boolean of $coll->ge($str, "abc") and
$coll->le($str, "abc\x{FFFF}") is true, it is expected that $str
begins with "abc", or another primary equivalent.
$str may be "abcd", "abc012", but should not include U+FFFF
such as "abc\x{FFFF}xyz".
$coll->le($str, "abc\x{FFFF}") works like $coll->lt($str, "abd")
almost, but the latter has a problem that you should know which letter is
next to c. For a certain language where ch as the next letter,
"abch" is greater than "abc\x{FFFF}", but less than "abd".
Note:
This is equivalent to (entry => 'FFFF ; [.FFFE.0020.0005.FFFF]').
Any other character than U+FFFF can be tailored by entry.
By default, strings whose weights are equal should be equal, even though their code points are not equal. Completely ignorable characters are ignored.
If the parameter is made true, a final, tie-breaking level is used.
If no difference of weights is found after the comparison through
all the level specified by level, the comparison with code points
will be performed.
For the tie-breaking comparison, the sort key has code points
of the original string appended.
Completely ignorable characters are not ignored.
If preprocess and/or normalization is applied, the code points
of the string after them (in NFD by default) are used.
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').
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.
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.
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.
NOTE: The DUCET includes weights over 0xFFFF at the 4th level.
But this module only uses weights within 0xFFFF.
When variable is 'blanked' or 'non-ignorable' (other than 'shifted'
and 'shift-trimmed'), the level 4 may be unreliable.
See also identical.
If the parameter is made true, for a contraction with three or more characters (here nicknamed ``long contraction''), initial substrings will be handled. For example, a contraction ABC, where A is a starter, and B and C are non-starters (character with non-zero combining character class), will be detected even if there is not AB as a contraction.
Default: Usually false.
If UCA_Version is 22 or 24, and the value of long_contraction
is not specified in new(), a true value is set implicitly.
This is a workaround to pass Conformance Tests for Unicode 6.0.0 and 6.1.0.
change() handles long_contraction explicitly only.
If long_contraction is not specified in change(), even though
UCA_Version is changed, long_contraction will not be changed.
Limitation: Scanning non-starters is one-way (no back tracking). If AB is found but not ABC is not found, other long contraction where the first character is A and the second is not B may not be found.
Under (normalization => undef), detection step of discontiguous
contractions will be skipped.
Note: The following contractions in DUCET are not considered in steps S2.1.1 to S2.1.3, where they are discontiguous.
0FB2 0F71 0F80 (TIBETAN VOWEL SIGN VOCALIC RR)
0FB3 0F71 0F80 (TIBETAN VOWEL SIGN VOCALIC LL)
For example TIBETAN VOWEL SIGN VOCALIC RR with COMBINING TILDE OVERLAY
(U+0344) is 0FB2 0344 0F71 0F80 in NFD.
In this case 0FB2 0F80 (TIBETAN VOWEL SIGN VOCALIC R) is detected,
instead of 0FB2 0F71 0F80.
Inserted 0344 makes 0FB2 0F71 0F80 discontiguous and lack of
contraction 0FB2 0F71 prohibits 0FB2 0F71 0F80 from being detected.
If the parameter is made true, U+FFFE has a minimal primary weight.
The comparison between "$a1\x{FFFE}$a2" and "$b1\x{FFFE}$b2"
first compares $a1 and $b1 at level 1, and
then $a2 and $b2 at level 1, as followed.
"ab\x{FFFE}a"
"Ab\x{FFFE}a"
"ab\x{FFFE}c"
"Ab\x{FFFE}c"
"ab\x{FFFE}xyz"
"abc\x{FFFE}def"
"abc\x{FFFE}xYz"
"aBc\x{FFFE}xyz"
"abcX\x{FFFE}def"
"abcx\x{FFFE}xyz"
"b\x{FFFE}aaa"
"bbb\x{FFFE}a"
Note:
This is equivalent to (entry => 'FFFE ; [.0001.0020.0005.FFFE]').
Any other character than U+FFFE can be tailored by entry.
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).
By default, CJK unified ideographs are ordered in Unicode codepoint order, but those in the CJK Unified Ideographs block are less 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 to 30.
U+4E00..U+9FD5 if UCA_Version is 32 or 34.
U+4E00..U+9FEA if UCA_Version is 36.
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 later.
Ext.D (U+2B740..U+2B81D) if UCA_Version is 22 or later.
Ext.E (U+2B820..U+2CEA1) if UCA_Version is 32 or later.
Ext.F (U+2CEB0..U+2EBE0) if UCA_Version is 36.
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 a false value (including undef) is passed, overrideCJK
has no effect.
$Collator->change(overrideCJK => 0) resets the old one.
But assignment of weight for CJK unified ideographs
in table or entry is still valid.
If undef is passed explicitly as the value for this key,
weights for CJK unified ideographs are treated as undefined.
However when UCA_Version > 8, (overrideCJK => undef)
has no special meaning.
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.
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 a false value (but not undef) is passed, overrideHangul
has no effect.
$Collator->change(overrideHangul => 0) resets the old one.
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.
Perl seems to allow out-of-range values (greater than 0x10FFFF).
By default, out-of-range values are replaced with U+FFFD
(REPLACEMENT CHARACTER) when UCA_Version >= 22,
or ignored when UCA_Version <= 20.
When UCA_Version >= 22, the weights of out-of-range values
can be overridden. Though table or entry are available for them,
out-of-range values are too many.
overrideOut can perform it algorithmically.
This parameter works like overrideCJK, so see there for examples.
ex. ignores all out-of-range values.
overrideOut => sub {()}, # CODEREF returning empty list
If a false value (including undef) is passed, overrideOut
has no effect.
$Collator->change(overrideOut => 0) resets the old one.
NOTE ABOUT U+FFFD:
UCA recommends that out-of-range values should not be ignored for security
reasons. Say, "pe\x{110000}rl" should not be equal to "perl".
However, U+FFFD is wrongly mapped to a variable collation element
in DUCET for Unicode 6.0.0 to 6.2.0, that means out-of-range values will be
ignored when variable isn't Non-ignorable.
The mapping of U+FFFD is corrected in Unicode 6.3.0.
see http://www.unicode.org/reports/tr10/tr10-28.html#Trailing_Weights
(7.1.4 Trailing Weights). Such a correction is reproduced by this.
overrideOut => sub { 0xFFFD }, # CODEREF returning a very large integer
This workaround is unnecessary since Unicode 6.3.0.
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 the perlunicode manpage, the perluniintro manpage, the perlunitut manpage, the perlunifaq manpage, the utf8 manpage.
Characters that are not coded in logical order and to be rearranged.
If UCA_Version is equal to or less 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.
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.
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 will not be suppressed.
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:
$onlyABC = Unicode::Collate->new(
table => undef,
entry => << 'ENTRIES',
0061 ; [.0101.0020.0002.0061] # LATIN SMALL LETTER A
0041 ; [.0101.0020.0008.0041] # LATIN CAPITAL LETTER A
0062 ; [.0102.0020.0002.0062] # LATIN SMALL LETTER B
0042 ; [.0102.0020.0008.0042] # LATIN CAPITAL LETTER B
0063 ; [.0103.0020.0002.0063] # LATIN SMALL LETTER C
0043 ; [.0103.0020.0008.0043] # LATIN CAPITAL LETTER C
ENTRIES
);
If ignoreName or undefName is used, character names should be
specified as a comment (following #) on each line.
Undefines the collation element as if it were unassigned in the table.
This reduces the size of the table.
If an unassigned character appears in the string to be collated,
the sort key is made from its codepoint
as a single-character collation element,
as it is greater than any other assigned collation elements
(in the codepoint order among the unassigned characters).
But, it'd be better to ignore characters
unfamiliar to you and maybe never used.
Through undefChar, any character matching qr/$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}]/,
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.
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.
@sorted = $Collator->sort(@not_sorted)$result = $Collator->cmp($a, $b)$a is greater than $b)
or 0 (when $a is equal to $b)
or -1 (when $a is less 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)eq : whether $a is equal to $b. ne : whether $a is not equal to $b. lt : whether $a is less than $b. le : whether $a is less 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)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)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
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 less.
$position = $Collator->index($string, $substring[, $position])($position, $length) = $Collator->index($string, $substring[, $position])$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. when the content of $str is "Ich muß studieren Perl.",
you say the following where $sub is "MüSS",
my $Collator = Unicode::Collate->new( normalization => undef, level => 1 );
# (normalization => undef) is REQUIRED.
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 "MüSS".
$match_ref = $Collator->match($string, $substring)($match) = $Collator->match($string, $substring)$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, $substring)$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, $replacement)$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, $replacement)$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.
%old_tailoring = $Collator->change(%new_tailoring)$modified_collator = $Collator->change(%new_tailoring)
$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()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()Base_Unicode_Version()
No method will be exported.
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.
normalization parameter requires the Unicode::Normalize
module (see the Unicode::Normalize manpage).
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.
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).
If UCA_Version is 26 or later, the identical level is preferred;
Unicode::Collate->new(identical => 1) and
Unicode::Collate->new(identical => 1,
variable => "non-ignorable", level => 3) should be used.
Unicode::Normalize is required to try The Conformance Test.
The Unicode::Collate module for perl was written by SADAHIRO Tomoyuki,
<SADAHIRO@cpan.org>. This module is Copyright(C) 2001-2018,
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/9.0.0/allkeys.txt. For this file, Copyright (c) 2016 Unicode, Inc.; distributed under the Terms of Use in http://www.unicode.org/terms_of_use.html
| Unicode::Collate - Unicode Collation Algorithm |