source: vendor/perl/5.8.8/pod/perlunicode.pod@ 3609

=head1 NAME

perlunicode - Unicode support in Perl

=head1 DESCRIPTION

=head2 Important Caveats

Unicode support is an extensive requirement. While Perl does not
implement the Unicode standard or the accompanying technical reports
from cover to cover, Perl does support many Unicode features.

=over 4

=item Input and Output Layers

Perl knows when a filehandle uses Perl's internal Unicode encodings
(UTF-8, or UTF-EBCDIC if in EBCDIC) if the filehandle is opened with
the ":utf8" layer.  Other encodings can be converted to Perl's
encoding on input or from Perl's encoding on output by use of the
":encoding(...)"  layer.  See L<open>.

To indicate that Perl source itself is using a particular encoding,
see L<encoding>.

=item Regular Expressions

The regular expression compiler produces polymorphic opcodes.  That is,
the pattern adapts to the data and automatically switches to the Unicode
character scheme when presented with Unicode data--or instead uses
a traditional byte scheme when presented with byte data.

=item C<use utf8> still needed to enable UTF-8/UTF-EBCDIC in scripts

As a compatibility measure, the C<use utf8> pragma must be explicitly
included to enable recognition of UTF-8 in the Perl scripts themselves
(in string or regular expression literals, or in identifier names) on
ASCII-based machines or to recognize UTF-EBCDIC on EBCDIC-based
machines.  B<These are the only times when an explicit C<use utf8>
is needed.>  See L<utf8>.

You can also use the C<encoding> pragma to change the default encoding
of the data in your script; see L<encoding>.

=item BOM-marked scripts and UTF-16 scripts autodetected

If a Perl script begins marked with the Unicode BOM (UTF-16LE, UTF16-BE,
or UTF-8), or if the script looks like non-BOM-marked UTF-16 of either
endianness, Perl will correctly read in the script as Unicode.
(BOMless UTF-8 cannot be effectively recognized or differentiated from
ISO 8859-1 or other eight-bit encodings.)

=item C<use encoding> needed to upgrade non-Latin-1 byte strings

By default, there is a fundamental asymmetry in Perl's unicode model:
implicit upgrading from byte strings to Unicode strings assumes that
they were encoded in I<ISO 8859-1 (Latin-1)>, but Unicode strings are
downgraded with UTF-8 encoding.  This happens because the first 256
codepoints in Unicode happens to agree with Latin-1.  

If you wish to interpret byte strings as UTF-8 instead, use the
C<encoding> pragma:

    use encoding 'utf8';

See L</"Byte and Character Semantics"> for more details.

=back

=head2 Byte and Character Semantics

Beginning with version 5.6, Perl uses logically-wide characters to
represent strings internally.

In future, Perl-level operations will be expected to work with
characters rather than bytes.

However, as an interim compatibility measure, Perl aims to
provide a safe migration path from byte semantics to character
semantics for programs.  For operations where Perl can unambiguously
decide that the input data are characters, Perl switches to
character semantics.  For operations where this determination cannot
be made without additional information from the user, Perl decides in
favor of compatibility and chooses to use byte semantics.

This behavior preserves compatibility with earlier versions of Perl,
which allowed byte semantics in Perl operations only if
none of the program's inputs were marked as being as source of Unicode
character data.  Such data may come from filehandles, from calls to
external programs, from information provided by the system (such as %ENV),
or from literals and constants in the source text.

The C<bytes> pragma will always, regardless of platform, force byte
semantics in a particular lexical scope.  See L<bytes>.

The C<utf8> pragma is primarily a compatibility device that enables
recognition of UTF-(8|EBCDIC) in literals encountered by the parser.
Note that this pragma is only required while Perl defaults to byte
semantics; when character semantics become the default, this pragma
may become a no-op.  See L<utf8>.

Unless explicitly stated, Perl operators use character semantics
for Unicode data and byte semantics for non-Unicode data.
The decision to use character semantics is made transparently.  If
input data comes from a Unicode source--for example, if a character
encoding layer is added to a filehandle or a literal Unicode
string constant appears in a program--character semantics apply.
Otherwise, byte semantics are in effect.  The C<bytes> pragma should
be used to force byte semantics on Unicode data.

If strings operating under byte semantics and strings with Unicode
character data are concatenated, the new string will be created by
decoding the byte strings as I<ISO 8859-1 (Latin-1)>, even if the
old Unicode string used EBCDIC.  This translation is done without
regard to the system's native 8-bit encoding.  To change this for
systems with non-Latin-1 and non-EBCDIC native encodings, use the
C<encoding> pragma.  See L<encoding>.

Under character semantics, many operations that formerly operated on
bytes now operate on characters. A character in Perl is
logically just a number ranging from 0 to 2**31 or so. Larger
characters may encode into longer sequences of bytes internally, but
this internal detail is mostly hidden for Perl code.
See L<perluniintro> for more.

=head2 Effects of Character Semantics

Character semantics have the following effects:

=over 4

=item *

Strings--including hash keys--and regular expression patterns may
contain characters that have an ordinal value larger than 255.

If you use a Unicode editor to edit your program, Unicode characters
may occur directly within the literal strings in one of the various
Unicode encodings (UTF-8, UTF-EBCDIC, UCS-2, etc.), but will be recognized
as such and converted to Perl's internal representation only if the
appropriate L<encoding> is specified.

Unicode characters can also be added to a string by using the
C<\x{...}> notation.  The Unicode code for the desired character, in
hexadecimal, should be placed in the braces. For instance, a smiley
face is C<\x{263A}>.  This encoding scheme only works for characters
with a code of 0x100 or above.

Additionally, if you

   use charnames ':full';

you can use the C<\N{...}> notation and put the official Unicode
character name within the braces, such as C<\N{WHITE SMILING FACE}>.


=item *

If an appropriate L<encoding> is specified, identifiers within the
Perl script may contain Unicode alphanumeric characters, including
ideographs.  Perl does not currently attempt to canonicalize variable
names.

=item *

Regular expressions match characters instead of bytes.  "." matches
a character instead of a byte.  The C<\C> pattern is provided to force
a match a single byte--a C<char> in C, hence C<\C>.

=item *

Character classes in regular expressions match characters instead of
bytes and match against the character properties specified in the
Unicode properties database.  C<\w> can be used to match a Japanese
ideograph, for instance.

(However, and as a limitation of the current implementation, using
C<\w> or C<\W> I<inside> a C<[...]> character class will still match
with byte semantics.)

=item *

Named Unicode properties, scripts, and block ranges may be used like
character classes via the C<\p{}> "matches property" construct and
the  C<\P{}> negation, "doesn't match property".

For instance, C<\p{Lu}> matches any character with the Unicode "Lu"
(Letter, uppercase) property, while C<\p{M}> matches any character
with an "M" (mark--accents and such) property.  Brackets are not
required for single letter properties, so C<\p{M}> is equivalent to
C<\pM>. Many predefined properties are available, such as
C<\p{Mirrored}> and C<\p{Tibetan}>.

The official Unicode script and block names have spaces and dashes as
separators, but for convenience you can use dashes, spaces, or
underbars, and case is unimportant. It is recommended, however, that
for consistency you use the following naming: the official Unicode
script, property, or block name (see below for the additional rules
that apply to block names) with whitespace and dashes removed, and the
words "uppercase-first-lowercase-rest". C<Latin-1 Supplement> thus
becomes C<Latin1Supplement>.

You can also use negation in both C<\p{}> and C<\P{}> by introducing a caret
(^) between the first brace and the property name: C<\p{^Tamil}> is
equal to C<\P{Tamil}>.

B<NOTE: the properties, scripts, and blocks listed here are as of
Unicode 3.2.0, March 2002, or Perl 5.8.0, July 2002.  Unicode 4.0.0
came out in April 2003, and Perl 5.8.1 in September 2003.>

Here are the basic Unicode General Category properties, followed by their
long form.  You can use either; C<\p{Lu}> and C<\p{UppercaseLetter}>,
for instance, are identical.

    Short       Long

    L           Letter
    LC          CasedLetter
    Lu          UppercaseLetter
    Ll          LowercaseLetter
    Lt          TitlecaseLetter
    Lm          ModifierLetter
    Lo          OtherLetter

    M           Mark
    Mn          NonspacingMark
    Mc          SpacingMark
    Me          EnclosingMark

    N           Number
    Nd          DecimalNumber
    Nl          LetterNumber
    No          OtherNumber

    P           Punctuation
    Pc          ConnectorPunctuation
    Pd          DashPunctuation
    Ps          OpenPunctuation
    Pe          ClosePunctuation
    Pi          InitialPunctuation
                (may behave like Ps or Pe depending on usage)
    Pf          FinalPunctuation
                (may behave like Ps or Pe depending on usage)
    Po          OtherPunctuation

    S           Symbol
    Sm          MathSymbol
    Sc          CurrencySymbol
    Sk          ModifierSymbol
    So          OtherSymbol

    Z           Separator
    Zs          SpaceSeparator
    Zl          LineSeparator
    Zp          ParagraphSeparator

    C           Other
    Cc          Control
    Cf          Format
    Cs          Surrogate   (not usable)
    Co          PrivateUse
    Cn          Unassigned

Single-letter properties match all characters in any of the
two-letter sub-properties starting with the same letter.
C<LC> and C<L&> are special cases, which are aliases for the set of
C<Ll>, C<Lu>, and C<Lt>.

Because Perl hides the need for the user to understand the internal
representation of Unicode characters, there is no need to implement
the somewhat messy concept of surrogates. C<Cs> is therefore not
supported.

Because scripts differ in their directionality--Hebrew is
written right to left, for example--Unicode supplies these properties in
the BidiClass class:

    Property    Meaning

    L           Left-to-Right
    LRE         Left-to-Right Embedding
    LRO         Left-to-Right Override
    R           Right-to-Left
    AL          Right-to-Left Arabic
    RLE         Right-to-Left Embedding
    RLO         Right-to-Left Override
    PDF         Pop Directional Format
    EN          European Number
    ES          European Number Separator
    ET          European Number Terminator
    AN          Arabic Number
    CS          Common Number Separator
    NSM         Non-Spacing Mark
    BN          Boundary Neutral
    B           Paragraph Separator
    S           Segment Separator
    WS          Whitespace
    ON          Other Neutrals

For example, C<\p{BidiClass:R}> matches characters that are normally
written right to left.

=back

=head2 Scripts

The script names which can be used by C<\p{...}> and C<\P{...}>,
such as in C<\p{Latin}> or C<\p{Cyrillic}>, are as follows:

    Arabic
    Armenian
    Bengali
    Bopomofo
    Buhid
    CanadianAboriginal
    Cherokee
    Cyrillic
    Deseret
    Devanagari
    Ethiopic
    Georgian
    Gothic
    Greek
    Gujarati
    Gurmukhi
    Han
    Hangul
    Hanunoo
    Hebrew
    Hiragana
    Inherited
    Kannada
    Katakana
    Khmer
    Lao
    Latin
    Malayalam
    Mongolian
    Myanmar
    Ogham
    OldItalic
    Oriya
    Runic
    Sinhala
    Syriac
    Tagalog
    Tagbanwa
    Tamil
    Telugu
    Thaana
    Thai
    Tibetan
    Yi

Extended property classes can supplement the basic
properties, defined by the F<PropList> Unicode database:

    ASCIIHexDigit
    BidiControl
    Dash
    Deprecated
    Diacritic
    Extender
    GraphemeLink
    HexDigit
    Hyphen
    Ideographic
    IDSBinaryOperator
    IDSTrinaryOperator
    JoinControl
    LogicalOrderException
    NoncharacterCodePoint
    OtherAlphabetic
    OtherDefaultIgnorableCodePoint
    OtherGraphemeExtend
    OtherLowercase
    OtherMath
    OtherUppercase
    QuotationMark
    Radical
    SoftDotted
    TerminalPunctuation
    UnifiedIdeograph
    WhiteSpace

and there are further derived properties:

    Alphabetic      Lu + Ll + Lt + Lm + Lo + OtherAlphabetic
    Lowercase       Ll + OtherLowercase
    Uppercase       Lu + OtherUppercase
    Math            Sm + OtherMath

    ID_Start        Lu + Ll + Lt + Lm + Lo + Nl
    ID_Continue     ID_Start + Mn + Mc + Nd + Pc

    Any             Any character
    Assigned        Any non-Cn character (i.e. synonym for \P{Cn})
    Unassigned      Synonym for \p{Cn}
    Common          Any character (or unassigned code point)
                    not explicitly assigned to a script

For backward compatibility (with Perl 5.6), all properties mentioned
so far may have C<Is> prepended to their name, so C<\P{IsLu}>, for
example, is equal to C<\P{Lu}>.

=head2 Blocks

In addition to B<scripts>, Unicode also defines B<blocks> of
characters.  The difference between scripts and blocks is that the
concept of scripts is closer to natural languages, while the concept
of blocks is more of an artificial grouping based on groups of 256
Unicode characters. For example, the C<Latin> script contains letters
from many blocks but does not contain all the characters from those
blocks. It does not, for example, contain digits, because digits are
shared across many scripts. Digits and similar groups, like
punctuation, are in a category called C<Common>.

For more about scripts, see the UTR #24:

   http://www.unicode.org/unicode/reports/tr24/

For more about blocks, see:

   http://www.unicode.org/Public/UNIDATA/Blocks.txt

Block names are given with the C<In> prefix. For example, the
Katakana block is referenced via C<\p{InKatakana}>.  The C<In>
prefix may be omitted if there is no naming conflict with a script
or any other property, but it is recommended that C<In> always be used
for block tests to avoid confusion.

These block names are supported:

    InAlphabeticPresentationForms
    InArabic
    InArabicPresentationFormsA
    InArabicPresentationFormsB
    InArmenian
    InArrows
    InBasicLatin
    InBengali
    InBlockElements
    InBopomofo
    InBopomofoExtended
    InBoxDrawing
    InBraillePatterns
    InBuhid
    InByzantineMusicalSymbols
    InCJKCompatibility
    InCJKCompatibilityForms
    InCJKCompatibilityIdeographs
    InCJKCompatibilityIdeographsSupplement
    InCJKRadicalsSupplement
    InCJKSymbolsAndPunctuation
    InCJKUnifiedIdeographs
    InCJKUnifiedIdeographsExtensionA
    InCJKUnifiedIdeographsExtensionB
    InCherokee
    InCombiningDiacriticalMarks
    InCombiningDiacriticalMarksforSymbols
    InCombiningHalfMarks
    InControlPictures
    InCurrencySymbols
    InCyrillic
    InCyrillicSupplementary
    InDeseret
    InDevanagari
    InDingbats
    InEnclosedAlphanumerics
    InEnclosedCJKLettersAndMonths
    InEthiopic
    InGeneralPunctuation
    InGeometricShapes
    InGeorgian
    InGothic
    InGreekExtended
    InGreekAndCoptic
    InGujarati
    InGurmukhi
    InHalfwidthAndFullwidthForms
    InHangulCompatibilityJamo
    InHangulJamo
    InHangulSyllables
    InHanunoo
    InHebrew
    InHighPrivateUseSurrogates
    InHighSurrogates
    InHiragana
    InIPAExtensions
    InIdeographicDescriptionCharacters
    InKanbun
    InKangxiRadicals
    InKannada
    InKatakana
    InKatakanaPhoneticExtensions
    InKhmer
    InLao
    InLatin1Supplement
    InLatinExtendedA
    InLatinExtendedAdditional
    InLatinExtendedB
    InLetterlikeSymbols
    InLowSurrogates
    InMalayalam
    InMathematicalAlphanumericSymbols
    InMathematicalOperators
    InMiscellaneousMathematicalSymbolsA
    InMiscellaneousMathematicalSymbolsB
    InMiscellaneousSymbols
    InMiscellaneousTechnical
    InMongolian
    InMusicalSymbols
    InMyanmar
    InNumberForms
    InOgham
    InOldItalic
    InOpticalCharacterRecognition
    InOriya
    InPrivateUseArea
    InRunic
    InSinhala
    InSmallFormVariants
    InSpacingModifierLetters
    InSpecials
    InSuperscriptsAndSubscripts
    InSupplementalArrowsA
    InSupplementalArrowsB
    InSupplementalMathematicalOperators
    InSupplementaryPrivateUseAreaA
    InSupplementaryPrivateUseAreaB
    InSyriac
    InTagalog
    InTagbanwa
    InTags
    InTamil
    InTelugu
    InThaana
    InThai
    InTibetan
    InUnifiedCanadianAboriginalSyllabics
    InVariationSelectors
    InYiRadicals
    InYiSyllables

=over 4

=item *

The special pattern C<\X> matches any extended Unicode
sequence--"a combining character sequence" in Standardese--where the
first character is a base character and subsequent characters are mark
characters that apply to the base character.  C<\X> is equivalent to
C<(?:\PM\pM*)>.

=item *

The C<tr///> operator translates characters instead of bytes.  Note
that the C<tr///CU> functionality has been removed.  For similar
functionality see pack('U0', ...) and pack('C0', ...).

=item *

Case translation operators use the Unicode case translation tables
when character input is provided.  Note that C<uc()>, or C<\U> in
interpolated strings, translates to uppercase, while C<ucfirst>,
or C<\u> in interpolated strings, translates to titlecase in languages
that make the distinction.

=item *

Most operators that deal with positions or lengths in a string will
automatically switch to using character positions, including
C<chop()>, C<chomp()>, C<substr()>, C<pos()>, C<index()>, C<rindex()>,
C<sprintf()>, C<write()>, and C<length()>.  Operators that
specifically do not switch include C<vec()>, C<pack()>, and
C<unpack()>.  Operators that really don't care include
operators that treats strings as a bucket of bits such as C<sort()>,
and operators dealing with filenames.

=item *

The C<pack()>/C<unpack()> letters C<c> and C<C> do I<not> change,
since they are often used for byte-oriented formats.  Again, think
C<char> in the C language.

There is a new C<U> specifier that converts between Unicode characters
and code points.

=item *

The C<chr()> and C<ord()> functions work on characters, similar to
C<pack("U")> and C<unpack("U")>, I<not> C<pack("C")> and
C<unpack("C")>.  C<pack("C")> and C<unpack("C")> are methods for
emulating byte-oriented C<chr()> and C<ord()> on Unicode strings.
While these methods reveal the internal encoding of Unicode strings,
that is not something one normally needs to care about at all.

=item *

The bit string operators, C<& | ^ ~>, can operate on character data.
However, for backward compatibility, such as when using bit string
operations when characters are all less than 256 in ordinal value, one
should not use C<~> (the bit complement) with characters of both
values less than 256 and values greater than 256.  Most importantly,
DeMorgan's laws (C<~($x|$y) eq ~$x&~$y> and C<~($x&$y) eq ~$x|~$y>)
will not hold.  The reason for this mathematical I<faux pas> is that
the complement cannot return B<both> the 8-bit (byte-wide) bit
complement B<and> the full character-wide bit complement.

=item *

lc(), uc(), lcfirst(), and ucfirst() work for the following cases:

=over 8

=item *

the case mapping is from a single Unicode character to another
single Unicode character, or

=item *

the case mapping is from a single Unicode character to more
than one Unicode character.

=back

Things to do with locales (Lithuanian, Turkish, Azeri) do B<not> work
since Perl does not understand the concept of Unicode locales.

See the Unicode Technical Report #21, Case Mappings, for more details.

=back

=over 4

=item *

And finally, C<scalar reverse()> reverses by character rather than by byte.

=back

=head2 User-Defined Character Properties

You can define your own character properties by defining subroutines
whose names begin with "In" or "Is".  The subroutines can be defined in
any package.  The user-defined properties can be used in the regular
expression C<\p> and C<\P> constructs; if you are using a user-defined
property from a package other than the one you are in, you must specify
its package in the C<\p> or C<\P> construct.

    # assuming property IsForeign defined in Lang::
    package main;  # property package name required
    if ($txt =~ /\p{Lang::IsForeign}+/) { ... }

    package Lang;  # property package name not required
    if ($txt =~ /\p{IsForeign}+/) { ... }


Note that the effect is compile-time and immutable once defined.

The subroutines must return a specially-formatted string, with one
or more newline-separated lines.  Each line must be one of the following:

=over 4

=item *

Two hexadecimal numbers separated by horizontal whitespace (space or
tabular characters) denoting a range of Unicode code points to include.

=item *

Something to include, prefixed by "+": a built-in character
property (prefixed by "utf8::") or a user-defined character property,
to represent all the characters in that property; two hexadecimal code
points for a range; or a single hexadecimal code point.

=item *

Something to exclude, prefixed by "-": an existing character
property (prefixed by "utf8::") or a user-defined character property,
to represent all the characters in that property; two hexadecimal code
points for a range; or a single hexadecimal code point.

=item *

Something to negate, prefixed "!": an existing character
property (prefixed by "utf8::") or a user-defined character property,
to represent all the characters in that property; two hexadecimal code
points for a range; or a single hexadecimal code point.

=item *

Something to intersect with, prefixed by "&": an existing character
property (prefixed by "utf8::") or a user-defined character property,
for all the characters except the characters in the property; two
hexadecimal code points for a range; or a single hexadecimal code point.

=back

For example, to define a property that covers both the Japanese
syllabaries (hiragana and katakana), you can define

    sub InKana {
        return <<END;
    3040\t309F
    30A0\t30FF
    END
    }

Imagine that the here-doc end marker is at the beginning of the line.
Now you can use C<\p{InKana}> and C<\P{InKana}>.

You could also have used the existing block property names:

    sub InKana {
        return <<'END';
    +utf8::InHiragana
    +utf8::InKatakana
    END
    }

Suppose you wanted to match only the allocated characters,
not the raw block ranges: in other words, you want to remove
the non-characters:

    sub InKana {
        return <<'END';
    +utf8::InHiragana
    +utf8::InKatakana
    -utf8::IsCn
    END
    }

The negation is useful for defining (surprise!) negated classes.

    sub InNotKana {
        return <<'END';
    !utf8::InHiragana
    -utf8::InKatakana
    +utf8::IsCn
    END
    }

Intersection is useful for getting the common characters matched by
two (or more) classes.

    sub InFooAndBar {
        return <<'END';
    +main::Foo
    &main::Bar
    END
    }

It's important to remember not to use "&" for the first set -- that
would be intersecting with nothing (resulting in an empty set).

You can also define your own mappings to be used in the lc(),
lcfirst(), uc(), and ucfirst() (or their string-inlined versions).
The principle is the same: define subroutines in the C<main> package
with names like C<ToLower> (for lc() and lcfirst()), C<ToTitle> (for
the first character in ucfirst()), and C<ToUpper> (for uc(), and the
rest of the characters in ucfirst()).

The string returned by the subroutines needs now to be three
hexadecimal numbers separated by tabulators: start of the source
range, end of the source range, and start of the destination range.
For example:

    sub ToUpper {
        return <<END;
    0061\t0063\t0041
    END
    }

defines an uc() mapping that causes only the characters "a", "b", and
"c" to be mapped to "A", "B", "C", all other characters will remain
unchanged.

If there is no source range to speak of, that is, the mapping is from
a single character to another single character, leave the end of the
source range empty, but the two tabulator characters are still needed.
For example:

    sub ToLower {
        return <<END;
    0041\t\t0061
    END
    }

defines a lc() mapping that causes only "A" to be mapped to "a", all
other characters will remain unchanged.

(For serious hackers only)  If you want to introspect the default
mappings, you can find the data in the directory
C<$Config{privlib}>/F<unicore/To/>.  The mapping data is returned as
the here-document, and the C<utf8::ToSpecFoo> are special exception
mappings derived from <$Config{privlib}>/F<unicore/SpecialCasing.txt>.
The C<Digit> and C<Fold> mappings that one can see in the directory
are not directly user-accessible, one can use either the
C<Unicode::UCD> module, or just match case-insensitively (that's when
the C<Fold> mapping is used).

A final note on the user-defined property tests and mappings: they
will be used only if the scalar has been marked as having Unicode
characters.  Old byte-style strings will not be affected.

=head2 Character Encodings for Input and Output

See L<Encode>.

=head2 Unicode Regular Expression Support Level

The following list of Unicode support for regular expressions describes
all the features currently supported.  The references to "Level N"
and the section numbers refer to the Unicode Technical Report 18,
"Unicode Regular Expression Guidelines", version 6 (Unicode 3.2.0,
Perl 5.8.0).

=over 4

=item *

Level 1 - Basic Unicode Support

        2.1 Hex Notation                        - done          [1]
            Named Notation                      - done          [2]
        2.2 Categories                          - done          [3][4]
        2.3 Subtraction                         - MISSING       [5][6]
        2.4 Simple Word Boundaries              - done          [7]
        2.5 Simple Loose Matches                - done          [8]
        2.6 End of Line                         - MISSING       [9][10]

        [ 1] \x{...}
        [ 2] \N{...}
        [ 3] . \p{...} \P{...}
        [ 4] support for scripts (see UTR#24 Script Names), blocks,