Unicode Character Database |
Revision | 5.1.0 |
Authors | Mark Davis and Ken Whistler |
Date | 2008-03-25 |
This Version | http://www.unicode.org/Public/5.1.0/ucd/UCD.html |
Previous Version | http://www.unicode.org/Public/5.0.0/ucd/UCD.html |
Latest Version | http://www.unicode.org/Public/UNIDATA/UCD.html |
This document describes the format and content of the Unicode Character Database (UCD)
This file and the files described herein are part of the Unicode Character Database and are governed by the terms of use at http://www.unicode.org/terms_of_use.html.
The References provide related information that is useful in understanding this document.
Warning: the information in this file does not completely describe the use and interpretation of Unicode character properties and behavior. It must be used in conjunction with the data in the other files in the Unicode Character Database, and relies on the notation and definitions supplied in The Unicode Standard. All chapter references are to Version 5.0.0 of the standard unless otherwise indicated.
The Unicode Character Database (UCD) is a set of files that define the Unicode character properties and internal mappings. This document describes the properties and files that are part of The Unicode Standard, Version 5.1.0 [U5.1.0]. For a description of the changes in this version, see Modification History.
The file structure for the UCD changed in Version 4.1.0. From that point on, the successive versions of the UCD are complete versions, so that users of the standard do not need to assemble the correct version of each file from different update directories for previous versions in order to have a complete set of files for a version. Each version is in a directory of the following form:
http://www.unicode.org/Public/5.1.0/ucd/
Within this directory the structure is the same as in versions prior to 4.1.0, with two changes:
For information on the meaning and application of the terms normative, informative, and provisional, see Section 3.5, "Properties" in the Unicode Standard, Version 5.0.
Files in the UCD use the following format, unless otherwise specified.
0000..007F; Basic Latin 0080..00FF; Latin-1 Supplement
# All code points not explicitly listed for Script # have the value Common (Zyyy).
03D2 ; FC_NFKC; 03C5 # L& GREEK UPSILON WITH HOOK SYMBOL 03D3 ; FC_NFKC; 03CD # L& GREEK UPSILON WITH ACUTE AND HOOK SYMBOL
1680 ; White_Space # Zs OGHAM SPACE MARK 180E ; White_Space # Zs MONGOLIAN VOWEL SEPARATOR 2000..200A ; White_Space # Zs [11] EN QUAD..HAIR SPACE
00BC..00BE ; numeric # No [3] VULGAR FRACTION ONE QUARTER..VULGAR FRACTION THREE QUARTERS
The following table describes the format and meaning of each property data file in the main directory of the UCD. (An index by property name, rather than file, is found at Properties.) The first column lists the files and the properties for which they contain data. The second column indicates the type of the property: String, Numeric, Enumeration (non-binary), Binary, Catalog, or Miscellaneous. Catalog properties have enumerated values which are expected to be regularly extended with successive versions of the Unicode Standard. This distinguishes them from Enumeration properties, whose enumerated values constitute a logical partition space, for which new values will generally not be added in successive versions of the standard. An example of a Catalog property is the Block property. Miscellaneous properties do not fit into the other property categories, and currently include character names, comments about characters, or the Unicode_Radical_Stroke property (a combination of numeric values). The third column indicates the status (Normative, Informative, or Provisional), and the fourth column provides a description of the data.
The files with a small number of properties are listed first, followed by the files with a large number of properties: DerivedCoreProperties.txt, DerivedNormalizationProps.txt, PropList.txt, and UnicodeData.txt. For UnicodeData, the field numbers are supplied in the description. In a number of cases, fields in a data file only contribute to a UCD property; for example, the name field in UnicodeData.txt does not provide all the values for the Name property; Jamo.txt must be used as well.
None of these properties should be used without consulting the relevant discussions in the Unicode Standard.
Where a data file does not explicitly list property values for all code points, the code points are given default property values. These default property values are documented in the data files, with the exception of UnicodeData.txt. For that case the default property values are listed below in parentheses after the property name, with (=) indicating the code point itself. The default property values are also documented in any corresponding extracted data file.
ArabicShaping.txt | |||
---|---|---|---|
Joining_Type Joining_Group |
E | N | Basic Arabic and Syriac character shaping properties, such as initial, medial and final
shapes. See Section 8.2 in [Unicode].
|
BidiMirroring.txt | |||
Bidi_Mirroring_Glyph | S | I | Properties for substituting characters in an implementation of bidirectional mirroring. See UAX #9: The Bidirectional Algorithm [BIDI]. Do not confuse this with the Bidi_Mirrored property. |
Blocks.txt | |||
Block | C | N | List of block names, which are arbitrary names for ranges of code points. See Chapter 17 in [Unicode]. |
CompositionExclusions.txt | |||
Composition_Exclusion | B | N | Properties for normalization. See UAX #15: Unicode Normalization Forms [Norm]. Unlike other files, CompositionExclusions simply lists the relevant code points. |
CaseFolding.txt | |||
Simple_Case_Folding Case_Folding |
S | N | Mapping from characters to their case-folded forms. This is an informative file containing
normative derived properties.
Derived from UnicodeData and SpecialCasing. Note: The case foldings are omitted in the data file if they are the same as the code point itself. |
DerivedAge.txt | |||
Age | C | N/I | This file shows when various code points were designated/assigned in successive versions of the Unicode standard. |
EastAsianWidth.txt | |||
East_Asian_Width | E | I | Properties for determining the choice of wide vs. narrow glyphs in East Asian contexts. Property values are described in UAX #11: East Asian Width [Width]. |
Hangul_Syllable_Type |
E | N | The values L, V, T, LV, and LVT used in Chapter 3 in [Unicode]. |
Jamo_Short_Name |
M | N | The Hangul Syllable names are derived from the Jamo Short Names, as described in Chapter 3 in [Unicode]. |
LineBreak.txt | |||
Line_Break | E | N | Properties for line breaking. For more information, see UAX #14: Line Breaking Properties [Line]. |
Name_Alias |
M | N | Normative formal aliases for character with erroneous names as described in Chapter 4. These aliases match exactly the formal aliases published in the code charts of the Unicode Standard. |
used in Decomposition Mappings | S | N | NormalizationCorrections lists code point differences for Normalization Corrigenda. For more information, see UAX #15: Unicode Normalization Forms [Norm]. |
PropertyAliases.txt | |||
n/a | S | N/I | Property names and abbreviations. These names can be used for XML formats of UCD data, for regular-expression property tests, and other programmatic textual descriptions of Unicode data. |
PropertyValueAliases.txt | |||
n/a | S | N/I | Property value names and abbreviations. These names can be used for XML formats of UCD data, for regular-expression property tests, and other programmatic textual descriptions of Unicode data. |
Scripts.txt | |||
Script | C | I | Default script values for use in regular expressions. For more information, see UAX #24: Script Names [Script]. |
SpecialCasing.txt | |||
Uppercase_Mapping Lowercase_Mapping Titlecase_Mapping |
S | I | Data for producing (in combination with Unicode Data) the full case mappings. |
Unihan.txt (for more information, see [UAX38]) | |||
Numeric_Type Numeric_Value |
E | I | The characters tagged with kPrimaryNumeric,
kAccountingNumeric, and
kOtherNumeric are given the Numeric_Type numeric,
and the values indicated.
Most characters have these properties based on values from the UnicodeData.txt data file. See Numeric_Type. |
Unicode_Radical_Stroke
|
M | I | The Unicode radical stroke count, based on the tag kRSUnicode. |
DerivedCoreProperties.txt | |||
Alphabetic | B | I | Characters with the Alphabetic property. For more information, see
Chapter 4 in [Unicode]. Generated from: Lu + Ll + Lt + Lm + Lo + Nl + Other_Alphabetic |
Default_Ignorable_Code_Point | B | N | For programmatic determination of default ignorable code points. New
characters that should be ignored in rendering (unless explicitly supported) will be assigned
in these ranges, permitting programs to correctly handle the default rendering of such
characters when not otherwise supported. For more information, see the FAQ
Display of Unsupported Characters,
and Section 5.20
in [Unicode].
Generated from |
Lowercase | B | I | Characters with the Lowercase property. For more information, see
Chapter 4 in [Unicode]. Generated from: Ll + Other_Lowercase |
Grapheme_Base | B | I | For programmatic determination of grapheme cluster boundaries. For more
information, see UAX #29: Text Boundaries [Breaks].
Generated from: [0..10FFFF] - Cc - Cf - Cs - Co - Cn - Zl - Zp - Grapheme_Extend |
Grapheme_Extend | B | I | For programmatic determination of grapheme cluster boundaries. For more
information, see UAX #29: Text Boundaries [Breaks].
Generated from: Me + Mn + Other_Grapheme_Extend Note: depending on an application's interpretation of Co (private use), they may be either in Grapheme_Base, or in Grapheme_Extend, or in neither. |
Grapheme_Link | B | I | Deprecated property, once proposed for programmatic determination of grapheme cluster boundaries.
Generated from: Canonical_Combining_Class=Virama |
ID_Start | B | I | Used to determine programming identifiers, as described in UAX #31: Identifier and Pattern Syntax [Pattern] |
ID_Continue | B | I | |
Math | B | I | Characters with the Math property. For more information, see
Chapter 4 in [Unicode]. Generated from: Sm + Other_Math |
Uppercase | B | I | Characters with the Uppercase property. For more information, see
Chapter 4 in [Unicode]. Generated from: Lu + Other_Uppercase |
XID_Start | B | I | Used to determine programming identifiers, as described in UAX #31: Identifier and Pattern Syntax [Pattern] |
XID_Continue | B | I | |
DerivedNormalizationProps.txt | |||
Full_Composition_Exclusion | B | N | Characters that are excluded from composition: those explicitly in
CompositionExclusions.txt, plus: (3) Singleton Decompositions (4) Non-Starter Decompositions |
Expands_On_NFC Expands_On_NFD Expands_On_NFKC Expands_On_NFKD |
B | N | Characters that expand to more than one character in the specified normalization form. |
FC_NFKC_Closure | S | N | Characters that require extra mappings for closure under Case Folding plus
Normalization Form KC. Characters marked with this property have a third field with the
mapping in it. Generated with the following, where Fold is the default fold operation (not
Turkic):
b = NFKC(Fold(a)); c = NFKC(Fold(b)); if (c != b) add mapping from a to c to the set of mappings that constitute the FC_NFKC_Closure list Note: The FC_NFKC_Closure value is omitted in the data file if it is the same as the code point itself. |
NFD_Quick_Check NFKD_Quick_Check NFC_Quick_Check NFKC_Quick_Check |
E | N | For property values, see Decompositions and Normalization. (Abbreviated names: NFD_QC, NFKD_QC, NFC_QC, NFKC_QC) |
PropList.txt | |||
ASCII_Hex_Digit | B | N | ASCII characters commonly used for the representation of hexadecimal numbers. |
Bidi_Control | B | N | Those format control characters which have specific functions in the Bidirectional Algorithm. |
Dash | B | I | Those punctuation characters explicitly called out as dashes in the Unicode Standard, plus compatibility equivalents to those. Most of these have the Pd General Category, but some have the Sm General Category because of their use in mathematics. |
Deprecated | B | N | For a machine-readable list of deprecated characters. No characters will ever be removed from the standard, but the usage of deprecated characters is strongly discouraged. |
Diacritic | B | I | Characters that linguistically modify the meaning of another character to which they apply. Some diacritics are not combining characters, and some combining characters are not diacritics. |
Extender | B | I | Characters whose principal function is to extend the value or shape of a preceding alphabetic character. Typical of these are length and iteration marks. |
Hex_Digit | B | I | Characters commonly used for the representation of hexadecimal numbers, plus their compatibility equivalents. |
Hyphen (Stabilized as of 3.2) | B | I | Those dashes used to mark connections between pieces of words, plus the Katakana middle dot. The Katakana middle dot functions like a hyphen, but is shaped like a dot rather than a dash. |
Ideographic | B | I | Characters considered to be CJKV (Chinese, Japanese, Korean, and Vietnamese) ideographs. |
IDS_Binary_Operator | B | N | Used in Ideographic Description Sequences. |
IDS_Trinary_Operator | B | N | Used in Ideographic Description Sequences. |
Join_Control | B | N | Those format control characters which have specific functions for control of cursive joining and ligation. |
Logical_Order_Exception | B | N | There are a small number of characters that do not use logical order. These characters require special handling in most processing. |
Noncharacter_Code_Point | B | N | Code points that are permanently reserved for internal use. |
Other_Alphabetic | B | I | Used in deriving the Alphabetic property. |
Other_Default_Ignorable_Code_Point | B | N | Used in deriving the Default_Ignorable_Code_Point property. |
Other_Grapheme_Extend | B | N | Used in deriving the Grapheme_Extend property. |
Other_ID_Continue | B | N | Used for backwards compatibility of ID_Continue |
Other_ID_Start | B | N | Used for backwards compatibility of ID_Start |
Other_Lowercase | B | I | Used in deriving the Lowercase property. |
Other_Math | B | I | Used in deriving the Math property. |
Other_Uppercase | B | I | Used in deriving the Uppercase property. |
Pattern_Syntax | B | N | Used for pattern syntax as described in UAX #31: Identifier and Pattern Syntax [Pattern]. |
Pattern_White_Space | B | N | |
Quotation_Mark | B | I | Those punctuation characters that function as quotation marks. |
Radical | B | N | Used in Ideographic Description Sequences. |
Soft_Dotted | B | N | Characters with a "soft dot", like i or j. An accent placed on these characters causes the dot to disappear. An explicit dot above can be added where required, such as in Lithuanian. |
STerm | B | I | Sentence Terminal. Used in UAX #29: Text Boundaries [Breaks]. |
Terminal_Punctuation | B | I | Those punctuation characters that generally mark the end of textual units. |
Unified_Ideograph | B | N | Used in Ideographic Description Sequences. |
Variation_Selector | B | N | Indicates all those characters that qualify as Variation Selectors. For details on the behavior of these characters, see StandardizedVariants.html and Section 16.4, Variation Selectors in [Unicode]. |
White_Space | B | N | Those separator characters and control characters which should be treated by
programming languages as "white space" for the purpose of parsing elements.
Note: ZERO WIDTH SPACE and ZERO WIDTH NO-BREAK SPACE are not included, since their functions are restricted to line-break control. Their names are unfortunately misleading in this respect. Note: There are other senses of "whitespace" that encompass a different set of characters. |
Name (<none>) | M | N | (1) These names match exactly the names published in the code charts of the
Unicode Standard. The Hangul Syllable names are omitted from this file; see Jamo.txt.
For UnicodeData.txt, default values for the property are shown in parentheses after the property name in this table. See PropertyValueAliases.txt for information on all default values. |
General_Category (Cn) | E | N | (2) This is a useful breakdown into various character types which can be used as a default categorization in implementations. For the property values, see General Category Values. |
Canonical_Combining_Class (0) | N | N | (3) The classes used for the Canonical Ordering Algorithm in the Unicode Standard. This property could be considered either an enumerated property or a numeric property: the principal use of the property is in terms of the numeric values. For the property value names associated with different numeric values, see DerivedCombiningClass.txt and Canonical Combining Class Values. |
Bidi_Class (L, AL, R) | E | N | (4) These are the categories required by the Bidirectional Behavior Algorithm
in the Unicode Standard. For the property values, see Bidi Class
Values. For more information, see UAX #9: The Bidirectional Algorithm [BIDI]. The default property values depend on the code point, and are given in extracted/DerivedBidiClass.txt |
Decomposition_Type (None) Decomposition_Mapping (<code point>) |
E S |
N | (5) This field contains both values, with the type in angle brackets. The
decomposition mappings match exactly the decomposition mappings published with the character
names in the Unicode Standard. For more information, see
Character Decomposition Mappings.
Note: The decomposition mapping is omitted in the data file if the decomposition mapping is the same as the code point itself. |
Numeric_Type (None) Numeric_Value (NaN) |
E N |
N | (6) If the character has the decimal digit property, as specified in Chapter 4 of the Unicode Standard, then the value of that digit is represented with an integer value in fields 6, 7, and 8. |
E N |
N | (7) If the character has the digit property, but is not a decimal digit, then the value of that digit is represented with an integer value in fields 7 and 8. This covers digits that need special handling, such as the compatibility superscript digits. | |
E N |
N | (8) If the character has the numeric property, as specified in Chapter
4 of the Unicode Standard, the value of that character is represented with a positive or
negative integer or rational number in this field. This includes fractions such as, e.g., "1/5" for
U+2155 VULGAR FRACTION ONE FIFTH.
Some characters have these properties based on values from the Unihan data file. See Numeric_Type, Han. |
|
Bidi_Mirrored (N) | B | N | (9) If the character has been identified as a "mirrored" character in bidirectional text, this field has the value "Y"; otherwise "N". The list of mirrored characters is also printed in Chapter 4 of the Unicode Standard. Do not confuse this with the Bidi_Mirroring_Glyph property. |
Unicode_1_Name (<none>) | M | I | (10) This is the old name as published in Unicode 1.0. This name is only provided when it is significantly different from the current name for the character. The value of field 10 for control characters does not always match the Unicode 1.0 names. Instead, field 10 contains ISO 6429 names for control functions, for printing in the code charts. |
ISO_Comment (<none>) | M | I | (11) This is the ISO 10646 comment field. It appears in parentheses in the 10646 names list, or contains an asterisk to mark an Annex P note. |
Simple_Uppercase_Mapping (<code point>) | S | N | (12) Simple uppercase mapping (single character result). If a character is
part of an alphabet with case distinctions, and has a simple upper case equivalent, then the
upper case equivalent is in this field. See the explanation below on case distinctions. The
simple mappings have a single character result, where the full mappings may have
multi-character results. For more information, see Case Mappings.
Note: The simple uppercase is omitted in the data file if the uppercase is the same as the code point itself. |
Simple_Lowercase_Mapping (<code point>) | S | N | (13) Simple lowercase mapping (single character result). Similar to Uppercase
mapping.
Note: The simple lowercase is omitted in the data file if the lowercase is the same as the code point itself. |
Simple_Titlecase_Mapping (<code point>) | S | N | (14) Similar to Uppercase mapping (single character result).
Note: The simple titlecase may be omitted in the data file if the titlecase is the same as the uppercase. |
Note:
Stabilized properties are no longer actively maintained, nor are they extended as new characters are added.
A number of auxiliary properties are contained in files in the auxiliary subdirectory. They consist of the following:
GraphemeBreakProperty.txt | N/I | ||
---|---|---|---|
Grapheme_Cluster_Break | E | I | See UAX #29: Text Boundaries [Breaks] |
SentenceBreakProperty.txt | |||
Sentence_Break | E | I | See UAX #29: Text Boundaries [Breaks] |
WordBreakProperty.txt | |||
Word_Break | E | I | See UAX #29: Text Boundaries [Breaks] |
The following properties of the UCD have been separated out, reformatted, and listed in range format, one property per file, except as noted. These files are provided purely as a reformatting of existing data, any exceptions are noted in the table below. All files for derived extracted properties are contained in a subdirectory called extracted.
Files | N/I | Definition and Generation | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
DerivedBidiClass | N | From UnicodeData.txt, field 4 | ||||||||
DerivedBinaryProperties | N | The Bidi_Mirrored property from UnicodeData.txt, field 9. See Bidi Note. | ||||||||
DerivedCombiningClass | N | From UnicodeData.txt, field 3 | ||||||||
DerivedDecompositionType | * | From the <tag> in UnicodeData.txt, field 5. For characters with canonical decomposition
mappings (no tag), the value "canonical" is used.
* The value "canonical" is normative; the others are informative. |
||||||||
DerivedEastAsianWidth | I | From EastAsianWidth.txt, field 1 | ||||||||
DerivedGeneralCategory | N | From UnicodeData.txt, field 2 | ||||||||
DerivedJoiningGroup | N | From ArabicShaping.txt, field 2 | ||||||||
DerivedJoiningType | N | From ArabicShaping.txt, field 1 | ||||||||
DerivedLineBreak | N | From LineBreak.txt, field 1. For more information, see UAX #14: Line Breaking Properties [Line]. | ||||||||
DerivedNumericType | N | The property value is based on the contents of UnicodeData.txt, fields 6 through 8:
|
||||||||
DerivedNumericValues | N | The numeric value from UnicodeData.txt, field 8 |
Bidi Note: The BidiMirrored property and the BidiMirroring property are different. The former is a normative property that indicates whether characters are mirrored in a right-to-left context in the Unicode Bidirectional Algorithm. The latter is an informative mapping of a subset of the BidiMirrored characters, to characters that normally have the corresponding mirrored glyph.
The following files in the Unicode Character Database are not used directly for Unicode properties. For more information about these files, see the referenced technical report(s), files, or section of Unicode Standard.
".txt" File | Description | N/I | Summary |
---|---|---|---|
Index | Chapter 17 | I | Index to Unicode characters, as printed in the Unicode Standard. |
NamesList | Chapter 17 | I | This file duplicates some of the material in the UnicodeData file, and adds annotations used in the character charts. |
NormalizationTest | UAX #15 | N | Test file for conformance to Unicode Normalization Forms. See UAX #15: Unicode Normalization Forms [Norm] |
StandardizedVariants | Chapter 16 | N | Lists all the standardized variant sequences that have been defined, plus a description of the desired appearance. StandardizedVariants.html contains this information, plus a sample glyph showing the desired features. |
NamedSequences | UAX#34 | N | List the names for all approved named sequences. |
NamedSequencesProv | UAX#34 | P | Lists the names for all provisional named sequences. |
The following table lists the properties in the UCD. They are roughly organized into groups based on the usage of the property (this grouping is purely for convenience, and has no other implications). The link on each property leads to description in the file index. The contributory properties (those of the form Other_XXX) are sets of exceptions used to generate properties in DerivedCoreProperties.txt. They are incomplete by themselves and not intended for independent use, for example an API returning property values would implement the corresponding derived core property instead.
Properties and property values may have multiple aliases, such as abbreviated names and longer, more descriptive names. For example, one can write either Line_Break or LB for the Line Break property, and either OP or Open_Punctuation for one of its values. When matching property names and values, it is strongly recommended that all aliases in the UCD be recognized, and that loose matching should be applied to all property names and property values according to the following:
For a general discussion of Unicode character properties, see Section 3.5, "Properties" in [Unicode], and UTR #23: The Unicode Character Property Model [UTR23].
Numeric Properties
For all numeric properties, and properties such as Unicode_Radical_Stroke that are combinations of numeric values, use the following loose matching rule:
LM1. Apply numeric equivalences
Character Names
LM2. Ignore case, whitespace, underscore ('_'), and all medial hyphens except the hyphen in U+1180.
Others
For all property names, property value names, and for property values for Enumerated, Binary, or Catalog properties, use the following loose matching rule:
LM3. Ignore case, whitespace, underscore ('_'), and hyphens.
Otherwise loose matching should not be done for the property values of String properties, as case distinctions or other distinctions in those values may be significant.
Values in the UCD are subject to correction as errors are found; however, some characteristics of the properties and files are considered invariants. Applications may wish to take these invariants into account when choosing how to implement character properties. All formally guaranteed invariants of property values are described in Unicode Policies. The following lists some additional invariants regarding file organization and more detail on a few of the invariants in the Unicode Policies.
The following gives a summary of property values for certain properties. Other property values are documented in other locations; for example, the line breaking property values are documented in UAX #14: Line Breaking Properties [Line].
The General_Category property of a code point provides for a most basic classification of that code point. It is usually determined based on the primary characteristic of the assigned character for that code point. For example, is it a letter, a mark, a number, punctuation, or a symbol, and if so, what type? Many characters have multiple uses, and not all such cases can be captured entirely by the General_Category value. For more information, see Chapter 4 in [Unicode].
The values in the General_Category field in UnicodeData.txt are abbreviations for the longer descriptions enumerated in the table below.
Abbr. |
Description |
---|---|
Lu | Letter, Uppercase |
Ll | Letter, Lowercase |
Lt | Letter, Titlecase |
Lm | Letter, Modifier |
Lo | Letter, Other |
Mn | Mark, Nonspacing |
Mc | Mark, Spacing Combining |
Me | Mark, Enclosing |
Nd | Number, Decimal Digit |
Nl | Number, Letter |
No | Number, Other |
Pc | Punctuation, Connector |
Pd | Punctuation, Dash |
Ps | Punctuation, Open |
Pe | Punctuation, Close |
Pi | Punctuation, Initial quote (may behave like Ps or Pe depending on usage) |
Pf | Punctuation, Final quote (may behave like Ps or Pe depending on usage) |
Po | Punctuation, Other |
Sm | Symbol, Math |
Sc | Symbol, Currency |
Sk | Symbol, Modifier |
So | Symbol, Other |
Zs | Separator, Space |
Zl | Separator, Line |
Zp | Separator, Paragraph |
Cc | Other, Control |
Cf | Other, Format |
Cs | Other, Surrogate |
Co | Other, Private Use |
Cn | Other, Not Assigned (no characters in the file have this property) |
Note: The term "L&" is used to stand for Uppercase, Lowercase or Titlecase letters (Lu, Ll, or Lt) in comments. The LC value in PropertyValueAliases.txt also stands for Uppercase, Lowercase or Titlecase letters.
Note: The Unicode Standard does not assign information to control characters (except for certain cases). Implementations will generally also assign categories to certain control characters, notably CR and LF, according to platform conventions. See Section 5.8 "Newline Guidelines" in [Unicode] for more information.
Please refer to UAX #9: The Bidirectional Algorithm [BIDI] for an explanation of the algorithm for Bidirectional Behavior and an explanation of the significance of these categories.
Type |
Description |
---|---|
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 |
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 |
The tags supplied with certain decomposition mappings generally indicate formatting information. Where no such tag is given, the mapping is canonical. Conversely, the presence of a formatting tag also indicates that the mapping is a compatibility mapping and not a canonical mapping. In the absence of other formatting information in a compatibility mapping, the tag is used to distinguish it from canonical mappings.
In some instances a canonical mapping or a compatibility mapping may consist of a single character. For a canonical mapping, this indicates that the character is a canonical equivalent of another single character. For a compatibility mapping, this indicates that the character is a compatibility equivalent of another single character. The compatibility formatting tags used are:
Tag |
Description |
---|---|
<font> | A font variant (e.g. a blackletter form). |
<noBreak> | A no-break version of a space or hyphen. |
<initial> | An initial presentation form (Arabic). |
<medial> | A medial presentation form (Arabic). |
<final> | A final presentation form (Arabic). |
<isolated> | An isolated presentation form (Arabic). |
<circle> | An encircled form. |
<super> | A superscript form. |
<sub> | A subscript form. |
<vertical> | A vertical layout presentation form. |
<wide> | A wide (or zenkaku) compatibility character. |
<narrow> | A narrow (or hankaku) compatibility character. |
<small> | A small variant form (CNS compatibility). |
<square> | A CJK squared font variant. |
<fraction> | A vulgar fraction form. |
<compat> | Otherwise unspecified compatibility character. |
Reminder: There is a difference between decomposition and decomposition mapping. The decomposition mappings are defined in the UnicodeData, while the decomposition (also termed "full decomposition") is defined in Chapter 3 to use those mappings recursively.
The normalization of Hangul conjoining jamos and of Hangul syllables depends on algorithmic mapping, as specified in Section 3.12, Conjoining Jamo Behavior in [Unicode]. That algorithm specifies the full decomposition of all precomposed Hangul syllables, but effectively it is equivalent to the recursive application of pairwise decomposition mappings, as for all other Unicode characters. Formally, the Decomposition_Mapping (dm) property value for a Hangul syllable is the pairwise decomposition and not the full decomposition.
Each character with the Hangul_Syllable_Type value LVT will have a decomposition mapping consisting of a character with an LV value and a character with a T value. Thus for U+CE31 the decomposition mapping is <U+CE20, U+11B8>, and not <U+110E, U+1173, U+11B8>.
Value |
Description |
---|---|
0: | Spacing, split, enclosing, reordrant, and Tibetan subjoined |
1: | Overlays and interior |
7: | Nuktas |
8: | Hiragana/Katakana voicing marks |
9: | Viramas |
10: | Start of fixed position classes |
199: | End of fixed position classes |
200: | Below left attached |
202: | Below attached |
204: | Below right attached |
208: | Left attached (reordrant around single base character) |
210: | Right attached |
212: | Above left attached |
214: | Above attached |
216: | Above right attached |
218: | Below left |
220: | Below |
222: | Below right |
224: | Left (reordrant around single base character) |
226: | Right |
228: | Above left |
230: | Above |
232: | Above right |
233: | Double below |
234: | Double above |
240: | Below (iota subscript) |
Note: some of the combining classes in this list do not currently have members but are specified here for completeness.
Decomposition is specified in Chapter 3. UAX #15: Unicode Normalization Forms [Norm] specifies the interaction between decomposition and normalization. That report specifies how the decompositions defined in UnicodeData.txt are used to derive normalized forms of Unicode text.
Note that as of the 2.1.9 update of the Unicode Character Database, the decompositions in the UnicodeData.txt file can be used to recursively derive the full decomposition in canonical order, without the need to separately apply canonical reordering. However, canonical reordering of combining character sequences must still be applied in decomposition when normalizing source text which contains any combining marks.
The QuickCheck property values are as follows:
Property | Value | Description |
---|---|---|
NF*_QC | No | Characters that cannot ever occur in the respective normalization form. See Decompositions and Normalization. |
NFC_QC, NFKC_QC | Maybe | Characters that may occur in the respective normalization, depending on the context. See Decompositions and Normalization. |
NF*_QC | Yes | All other characters. This is the default value, and is not listed for individual characters or ranges in the file. |
For more information, see Section 14 in UAX #15: Unicode Normalization Forms [Norm].
There are a number of complications to case mappings that occur once the repertoire of characters is expanded beyond ASCII. For more information, see Chapter 3 in Unicode 5.0.
For compatibility with existing parsers, UnicodeData.txt only contains case mappings for characters where they are one-to-one mappings; it also omits information about context-sensitive case mappings. Information about these special cases can be found in a separate data file, SpecialCasing.txt.
A large number of properties specific to Han ideographs are contained in the Unihan Database, where they are called Unihan tags. The Unihan.txt file is described in [UAX38].
Binary properties are expressed in the Unicode files with the values:
Value | Abbr | Alias | Abbr |
---|---|---|---|
Yes | Y | True | T |
No | N | False | F |
The property values for strings and catalog values as expressed in the UCD files can be validated by using the following Regular Expression expressions. These expressions use Perl syntax, but may be translated for use with other regular expression engines. The last column lists the default values for these properties.
Abbr | Name | Regex for Allowable Values | Defaults for Unlisted Values | |
age | Age | /([0-9]+\.[0-9]|unassigned)/ | unassigned | |
nv | Numeric_Value | /-?[0-9]+\.[0-9]+/ | Field 2 | NaN |
/-?[0-9]+(\[0-9]+)?/ | Field 3 | |||
blk | Block | /[a-zA-Z0-9]+([_\ ][a-zA-Z0-9]+)*/ | No_Block | |
sc | Script | Unknown (Zzzz) | ||
dm | Decomposition_Mapping | /[\x{0}-\x{10FFFF}]+/ | The code point itself, but # can be used to represent that in certain circumstances. | |
FC_NFKC | FC_NFKC_Closure | |||
cf | Case_Folding | /[\x{0}-\x{10FFFF}]+/ | ||
lc | Lowercase_Mapping | |||
tc | Titlecase_Mapping | |||
uc | Uppercase_Mapping | |||
sfc | Simple_Case_Folding | /[\x{0}-\x{10FFFF}]/ | ||
slc | Simple_Lowercase_Mapping | |||
stc | Simple_Titlecase_Mapping | |||
suc | Simple_Uppercase_Mapping | |||
bmg | Bidi_Mirroring_Glyph | /[\x{0}-\x{10FFFF}]?/ | "" | |
isc | ISO_Comment | /([A-Z0-9]+(([-\ ]|\ -|-\
)[A-Z0-9]+)*|\ |
||
na1 | Unicode_1_Name | /([A-Z0-9]+(([-\ ]|\ -|-\ )[A-Z0-9]+)*(\ \((CR|FF|LF|NEL)\))?)?/ |
null or empty string is the default
for these property values, however in files the following can be used: The code point can also appear, in a form like <private-use-E000>. In some circumstances, such as a compact XML format, # can be used to stand for the code point to allow for name sharing. |
|
na | Name | /([A-Z0-9]+(([-\ ]|\ -|-\
)[A-Z0-9]+)*|\ |
[BIDI] | UAX #9: The Bidirectional Algorithm Latest version: http://www.unicode.org/reports/tr9/ 5.1.0 version: http://www.unicode.org/reports/tr9/tr9-18.html |
[Breaks] | UAX #29: Text Boundaries Latest Version: http://www.unicode.org/reports/tr29/ 5.1.0 version: http://www.unicode.org/reports/tr29/tr29-13.html |
[FAQ] | Unicode Frequently Asked Questions http://www.unicode.org/faq/ For answers to common questions on technical issues. |
[Glossary] | Unicode Glossary http://www.unicode.org/glossary/ For explanations of terminology used in this and other documents. |
[Line] | UAX #14: Line Breaking Properties Latest Version: http://www.unicode.org/reports/tr14/ 5.1.0 version: http://www.unicode.org/reports/tr14/tr14-22.html |
[Norm] | UAX #15: Unicode Normalization Forms Latest Version: http://www.unicode.org/reports/tr15/ 5.1.0 version: http://www.unicode.org/reports/tr15/tr15-29.html |
[Pattern] | UAX #31: Identifier and Pattern Syntax Latest Version: http://www.unicode.org/reports/tr31/ 5.1.0 version: http://www.unicode.org/reports/tr31/tr31-9.html |
[Reports] | Unicode Technical Reports http://www.unicode.org/reports/ For information on the status and development process for technical reports, and for a list of technical reports. |
[Scripts] | UAX #24 Script Names http://www.unicode.org/reports/tr24/ 5.1.0 version: http://www.unicode.org/reports/tr24/tr24-11.html |
[U5.0] | The Unicode Standard Version 5.0 http://www.unicode.org/versions/Unicode5.0.0/ |
[U5.1.0] | The Unicode Standard Version 5.1.0 http://www.unicode.org/versions/Unicode5.1.0/ |
[UAX38] | UAX #38: Unicode Han Database (Unihan) Latest version: http://www.unicode.org/reports/tr38/ 5.1.0 version: http://www.unicode.org/reports/tr38/tr38-5.html |
[UTR23] | The Unicode Character Property Model http://www.unicode.org/reports/tr23/ |
[Versions] | Versions of the Unicode Standard http://www.unicode.org/versions/ For details on the precise contents of each version of the Unicode Standard, and how to cite them. |
[Width] | UAX #11: East Asian Width Latest Version: http://www.unicode.org/reports/tr11/ 5.1.0 version: http://www.unicode.org/reports/tr11/tr11-16.html |
This section provides a summary of the changes between update versions of the Unicode Standard. The modifications prior to Unicode 4.0 only listed changes in UnicodeData.txt. From 4.0 onward, the consolidated modifications include the changes in other files.
This document:
Changes in specific files:
In some of the following entries, references are made to a Public Review Issue (PRI). See http://www.unicode.org/review/resolved-pri.html for more information about those cases.
Appropriate data files were updated to include the 1624 new characters added in Unicode 5.1.
This document:
Common file changes:
In many data files an explicit default property assignment range was added (in a machine-readable comment line), to assist implementations in assigning values for code points not otherwise listed in the data file.
Changes in specific files:
In some of the following entries, references are made to a Public Review Issue (PRI). See http://www.unicode.org/review/resolved-pri.html for more information about those cases.
Appropriate data files were updated to include the 1369 new characters added in Unicode 5.0.
Two new data files, NameAliases.txt and NamedSequencesProv.txt, were added to the UCD.
Note that except for the changes involving U+0294 LATIN LETTER GLOTTAL STOP, changes made to General_Category and Bidirectional_Class impacted primarily a handful of archaic letters.
This document:
Common file changes:
All remaining files not corrected for Unicode 4.0.1 have had their headers updated to explicitly point to Terms of Use. The headers have also been synchronized somewhat to share a more common format for file version, date, and pointers to documentation. The major exception is UnicodeData.txt, which for legacy reasons, has no header.
Changes in specific files:
In some of the following, reference is made to a Public Review Issue (PRI). See http://www.unicode.org/review/resolved-pri.html for more information about those cases.
Appropriate data files were updated to include the 1273 new characters added in Unicode 4.1.
The description of the Unihan properties was separated out from UCD.html, and extensively revised, and now appears in Unihan.html.
An auxiliary directory has been added. In 4.1.0 it contains properties associated with UAX #29: Text Boundaries [Breaks].
This document:
Common file changes:
Some property values have different casing (upper vs. lower) for consistency between the data files and the PropertyValueAlias file. There are some additional changes in comments:
Changes in specific files:
In some of the following, reference is made to a Public Review Issue (PRI). See http://www.unicode.org/review/resolved-pri.html for more information about those cases.
Modifications made for Version 3.2.0 of UnicodeData.txt include:
- Addition of 1016 new entries, to cover new characters encoded in Unicode 3.2.
- Updated ISO 6429 names for control functions to match the currently published version of that standard.
- Changed general category for Mongolian free variation selectors (U+180B..U+180D) from Cf to Mn.
- Changed general category for U+0B83 TAMIL SIGN VISARGA (aytham) from Mc to Lo.
- Changed general category for U+06DD ARABIC END OF AYAH from Me to Cf.
- Changed general category for U+17D7 KHMER SIGN LEK TOO from Po to Lm.
- Changed general category for U+17DC KHMER SIGN AVAKRAHASANYA from Po to Lo.
- Changed canonical decomposition for U+F951 from 96FB to 964B (see Corrigendum #3: U+F951 Normalization).
Modifications made for Version 3.1.1 of UnicodeData.txt include:
Modifications made for Version 3.1.0 of UnicodeData.txt include:
Modifications made for Version 3.0.1 of UnicodeData.txt include:
Modifications made for Version 3.0.0 of UnicodeData.txt include many new characters and a number of property changes. These are summarized in Appendix D of The Unicode Standard, Version 3.0.
Modifications made for Version 2.1.9 of UnicodeData.txt include:
Modifications made for Version 2.1.8 of UnicodeData.txt include:
This version was for internal change tracking only, and never publicly released.
This version was for internal change tracking only, and never publicly released.
Modifications made for Version 2.1.5 of UnicodeData.txt include:
This version was for internal change tracking only, and never publicly released.
This version was for internal change tracking only, and never publicly released.
Modifications made in updating UnicodeData.txt to Version 2.1.2 for the Unicode Standard, Version 2.1 (from Version 2.0) include:
This version was for internal change tracking only, and never publicly released.
The modifications made in updating UnicodeData.txt for the Unicode Standard, Version 2.0 include:
For terms of use, see http://www.unicode.org/terms_of_use.html.