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132 lines
5 KiB
TeX
132 lines
5 KiB
TeX
\section{\module{unicodedata} ---
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Unicode Database}
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\declaremodule{standard}{unicodedata}
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\modulesynopsis{Access the Unicode Database.}
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\moduleauthor{Marc-Andre Lemburg}{mal@lemburg.com}
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\sectionauthor{Marc-Andre Lemburg}{mal@lemburg.com}
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\sectionauthor{Martin v. L\"owis}{martin@v.loewis.de}
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\index{Unicode}
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\index{character}
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\indexii{Unicode}{database}
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This module provides access to the Unicode Character Database which
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defines character properties for all Unicode characters. The data in
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this database is based on the \file{UnicodeData.txt} file version
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3.2.0 which is publically available from \url{ftp://ftp.unicode.org/}.
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The module uses the same names and symbols as defined by the
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UnicodeData File Format 3.2.0 (see
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\url{http://www.unicode.org/Public/UNIDATA/UnicodeData.html}). It
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defines the following functions:
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\begin{funcdesc}{lookup}{name}
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Look up character by name. If a character with the
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given name is found, return the corresponding Unicode
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character. If not found, \exception{KeyError} is raised.
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\end{funcdesc}
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\begin{funcdesc}{name}{unichr\optional{, default}}
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Returns the name assigned to the Unicode character
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\var{unichr} as a string. If no name is defined,
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\var{default} is returned, or, if not given,
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\exception{ValueError} is raised.
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\end{funcdesc}
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\begin{funcdesc}{decimal}{unichr\optional{, default}}
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Returns the decimal value assigned to the Unicode character
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\var{unichr} as integer. If no such value is defined,
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\var{default} is returned, or, if not given,
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\exception{ValueError} is raised.
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\end{funcdesc}
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\begin{funcdesc}{digit}{unichr\optional{, default}}
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Returns the digit value assigned to the Unicode character
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\var{unichr} as integer. If no such value is defined,
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\var{default} is returned, or, if not given,
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\exception{ValueError} is raised.
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\end{funcdesc}
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\begin{funcdesc}{numeric}{unichr\optional{, default}}
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Returns the numeric value assigned to the Unicode character
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\var{unichr} as float. If no such value is defined, \var{default} is
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returned, or, if not given, \exception{ValueError} is raised.
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\end{funcdesc}
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\begin{funcdesc}{category}{unichr}
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Returns the general category assigned to the Unicode character
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\var{unichr} as string.
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\end{funcdesc}
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\begin{funcdesc}{bidirectional}{unichr}
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Returns the bidirectional category assigned to the Unicode character
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\var{unichr} as string. If no such value is defined, an empty string
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is returned.
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\end{funcdesc}
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\begin{funcdesc}{combining}{unichr}
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Returns the canonical combining class assigned to the Unicode
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character \var{unichr} as integer. Returns \code{0} if no combining
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class is defined.
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\end{funcdesc}
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\begin{funcdesc}{east_asian_width}{unichr}
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Returns the east asian width assigned to the Unicode character
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\var{unichr} as string.
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\versionadded{2.4}
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\end{funcdesc}
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\begin{funcdesc}{mirrored}{unichr}
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Returns the mirrored property assigned to the Unicode character
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\var{unichr} as integer. Returns \code{1} if the character has been
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identified as a ``mirrored'' character in bidirectional text,
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\code{0} otherwise.
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\end{funcdesc}
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\begin{funcdesc}{decomposition}{unichr}
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Returns the character decomposition mapping assigned to the Unicode
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character \var{unichr} as string. An empty string is returned in case
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no such mapping is defined.
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\end{funcdesc}
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\begin{funcdesc}{normalize}{form, unistr}
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Return the normal form \var{form} for the Unicode string \var{unistr}.
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Valid values for \var{form} are 'NFC', 'NFKC', 'NFD', and 'NFKD'.
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The Unicode standard defines various normalization forms of a Unicode
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string, based on the definition of canonical equivalence and
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compatibility equivalence. In Unicode, several characters can be
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expressed in various way. For example, the character U+00C7 (LATIN
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CAPITAL LETTER C WITH CEDILLA) can also be expressed as the sequence
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U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING CEDILLA).
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For each character, there are two normal forms: normal form C and
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normal form D. Normal form D (NFD) is also known as canonical
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decomposition, and translates each character into its decomposed form.
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Normal form C (NFC) first applies a canonical decomposition, then
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composes pre-combined characters again.
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In addition to these two forms, there two additional normal forms
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based on compatibility equivalence. In Unicode, certain characters are
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supported which normally would be unified with other characters. For
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example, U+2160 (ROMAN NUMERAL ONE) is really the same thing as U+0049
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(LATIN CAPITAL LETTER I). However, it is supported in Unicode for
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compatibility with existing character sets (e.g. gb2312).
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The normal form KD (NFKD) will apply the compatibility decomposition,
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i.e. replace all compatibility characters with their equivalents. The
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normal form KC (NFKC) first applies the compatibility decomposition,
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followed by the canonical composition.
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\versionadded{2.3}
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\end{funcdesc}
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In addition, the module exposes the following constant:
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\begin{datadesc}{unidata_version}
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The version of the Unicode database used in this module.
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\versionadded{2.3}
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\end{datadesc}
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