X Locale Database Specification

Yoshio Horiuchi

   IBM Japan

   X Version 11, Release 7.7

   Copyright © 1994 IBM Corporation

   License to use, copy, modify, and distribute this software and
   its documentation for any purpose and without fee is hereby
   granted, provided that the above copyright notice appear in all
   copies and that both that copyright notice and this permission
   notice appear in supporting documentation, and that the name of
   IBM not be used in advertising or publicity pertaining to
   distribution of the software without specific, written prior
   permission.

   IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
   INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS,
   AND NONINFRINGEMENT OF THIRD PARTY RIGHTS, IN NO EVENT SHALL
   IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
   DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
   DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
   OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH
   THE USE OR PERFORMANCE OF THIS SOFTWARE.

   Copyright © 1994 X Consortium

   Permission is hereby granted, free of charge, to any person
   obtaining a copy of this software and associated documentation
   files (the "Software"), to deal in the Software without
   restriction, including without limitation the rights to use,
   copy, modify, merge, publish, distribute, sublicense, and/or
   sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following
   conditions:

   The above copyright notice and this permission notice shall be
   included in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE
   FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.

   Except as contained in this notice, the name of the X
   Consortium shall not be used in advertising or otherwise to
   promote the sale, use or other dealings in this Software
   without prior written authorization from the X Consortium.

   X Window System is a trademark of The Open Group.
     __________________________________________________________

   Table of Contents

   1. LocaleDB

        General
        Database Format Definition
        Contents of Database
        XLC_FONTSET Category
        XLC_XLOCALE Category
        Sample of X Locale Database
        Reference

Chapter 1. LocaleDB

   Table of Contents

   General
   Database Format Definition
   Contents of Database
   XLC_FONTSET Category
   XLC_XLOCALE Category
   Sample of X Locale Database
   Reference

General

   An X Locale Database contains the subset of a user's
   environment that depends on language, in X Window System. It is
   made up from one or more categories. Each category consists of
   some classes and sub-classes.

   It is provided as a plain ASCII text file, so a user can change
   its contents easily. It allows a user to customize the behavior
   of internationalized portion of Xlib without changing Xlib
   itself.

   This document describes;
     * Database Format Definition
     * Contents of Database in sample implementation

   Since it is hard to define the set of required information for
   all platforms, only the flexible database format is defined.
   The available entries in database are implementation dependent.

Database Format Definition

   The X Locale Database contains one or more category
   definitions. This section describes the format of each category
   definition.

   The category definition consists of one or more class
   definitions. Each class definition has a pair of class name and
   class value, or has several subclasses which are enclosed by
   the left brace ({) and the right brace (}).

   Comments can be placed by using the number sign character (#).
   Putting the number sign character on the top of the line
   indicates that the entire line is comment. Also, putting any
   whitespace character followed by the number sign character
   indicates that a part of the line (from the number sign to the
   end of the line) is comment. A line can be continued by placing
   backslash (\) character as the last character on the line; this
   continuation character will be discarded from the input.
   Comment lines cannot be continued on a subsequent line using an
   escaped new line character.

   X Locale Database only accepts XPCS, the X Portable Character
   Set. The reserved symbols are; the quotation mark("), the
   number sign (#), the semicolon(;), the backslash(\), the left
   brace({) and the right brace(}).

   The format of category definition is;
   CategoryDefinition ::= CategoryHeader CategorySpec
   CategoryTrailer
   CategoryHeader ::= CategoryName NL
   CategorySpec ::= { ClassSpec }
   CategoryTrailer ::= "END" Delimiter CategoryName NL
   CategoryName ::= String
   ClassSpec ::= ClassName Delimiter ClassValue NL
   ClassName ::= String
   ClassValue ::= ValueList | "{" NL { ClassSpec } "}"
   ValueList ::= Value | Value ";" ValueList
   Value ::= ValuePiece | ValuePiece Value
   ValuePiece ::= String | QuotedString | NumericString
   String ::= Char { Char }
   QuotedString ::= """ QuotedChar { QuotedChar } """
   NumericString ::= "\\o" OctDigit { OctDigit }
     | "\\d" DecDigit { DecDigit }
     | "\\x" HexDigit { HexDigit }
   Char ::= <XPCS except NL, Space or unescaped reserved symbols>
   QuotedChar ::= <XPCS except unescaped """>
   OctDigit ::= <character in the range of "0" - "7">
   DecDigit ::= <character in the range of "0" - "9">
   HexDigit ::= <character in the range of "0" - "9", "a" - "f",
   "A" - "F">
   Delimiter ::= Space { Space }
   Space ::= <space> | <horizontal tab>
   NL ::= <newline>

   Elements separated by vertical bar (|) are alternatives. Curly
   braces ({...}) indicate zero or more repetitions of the
   enclosed elements. Square brackets ([...]) indicate that the
   enclosed element is optional. Quotes ("...") are used around
   literal characters.

   The backslash, which is not the top character of the
   NumericString, is recognized as an escape character, so that
   the next one character is treated as a literal character. For
   example, the two-character sequence, ""\"""(the backslash
   followed by the quotation mark) is recognized and replaced with
   a quotation mark character. Any whitespace character, that is
   not the Delimiter, unquoted and unescaped, is ignored.

Contents of Database

   The available categories and classes depend on implementation,
   because different platform will require different information
   set. For example, some platform have system locale but some
   platform don't. Furthermore, there might be a difference in
   functionality even if the platform has system locale.

   In current sample implementation, categories listed below are
   available.
   XLC_FONTSET:XFontSet relative information
   XLC_XLOCALE:Character classification and conversion information

XLC_FONTSET Category

   The XLC_FONTSET category defines the XFontSet relative
   information. It contains the CHARSET_REGISTRY-CHARSET_ENCODING
   name and character mapping side (GL, GR, etc), and is used in
   Output Method (OM).
   class   super class description
   fsN                 Nth fontset (N=0,1,2, ...)
   charset fsN         list of encoding name
   font    fsN         list of font encoding name

   fsN

   Includes an encoding information for Nth charset, where N is
   the index number (0,1,2,...). If there are 4 charsets available
   in current locale, 4 fontsets, fs0, fs1, fs2 and fs3, should be
   defined. This class has two subclasses, 'charset' and 'font'.

   charset

   Specifies an encoding information to be used internally in Xlib
   for this fontset. The format of value is;
   EncodingInfo ::= EncodingName [ ":" EncodingSide ]
   EncodingName ::= CHARSET_REGISTRY-CHARSET_ENCODING
   EncodingSide ::= "GL" | "GR"

   For detail definition of CHARSET_REGISTRY-CHARSET_ENCODING,
   refer to the X Logical Font Description Conventions document.

   example:
        ISO8859-1:GL

   font

   Specifies a list of encoding information which is used for
   searching appropriate font for this fontset. The left most
   entry has highest priority.

XLC_XLOCALE Category

   The XLC_XLOCALE category defines character classification,
   conversion and other character attributes.
   class                 super class description
   encoding_name                     codeset name
   mb_cur_max                        MB_CUR_MAX
   state_depend_encoding             state dependent or not
   wc_encoding_mask                  for parsing wc string
   wc_shift_bits                     for conversion between wc and mb
   csN                               Nth charset (N=0,1,2,...)
   side                  csN         mapping side (GL, etc)
   length                csN         length of a character
   mb_encoding           csN         for parsing mb string
   wc_encoding           csN         for parsing wc string
   ct_encoding           csN         list of encoding name for ct

   encoding_name

   Specifies a codeset name of current locale.

   mb_cur_max

   Specifies a maximum allowable number of bytes in a multi-byte
   character. It is corresponding to MB_CUR_MAX of "ISO/IEC
   9899:1990 C Language Standard".

   state_depend_encoding

   Indicates a current locale is state dependent. The value should
   be specified "True" or "False".

   wc_encoding_mask

   Specifies a bit-mask for parsing wide-char string. Each wide
   character is applied bit-and operation with this bit-mask, then
   is classified into the unique charset, by using 'wc_encoding'.

   wc_shift_bits

   Specifies a number of bit to be shifted for converting from a
   multi-byte character to a wide character, and vice-versa.

   csN

   Includes a character set information for Nth charset, where N
   is the index number (0,1,2,...). If there are 4 charsets
   available in current locale, cs0, cs1, cs2 and cs3 should be
   defined. This class has five subclasses, 'side', 'length',
   'mb_encoding' 'wc_encoding' and 'ct_encoding'.

   side

   Specifies a mapping side of this charset. The format of this
   value is;

      Side    ::=  EncodingSide[":Default"]

   The suffix ":Default" can be specified. It indicates that a
   character belongs to the specified side is mapped to this
   charset in initial state.

   length

   Specifies a number of bytes of a multi-byte character of this
   charset. It should not contain the length of any single-shift
   sequence.

   mb_encoding

   Specifies a list of shift sequence for parsing multi-byte
   string. The format of this value is;
   MBEncoding    ::= ShiftType ShiftSequence
                 |   ShiftType ShiftSequence ";" MBEncoding
   ShiftType     ::= "<SS>"|"<LSL>"|"<LSR>"
   ShiftSequence ::= SequenceValue|SequenceValue ShiftSequence
   SequenceValue ::= NumericString

   example:
        <LSL> \x1b \x28 \x4a; <LSL> \x1b \x28 \x42

   wc_encoding

   Specifies an integer value for parsing wide-char string. It is
   used to determine the charset for each wide character, after
   applying bit-and operation using 'wc_encoding_mask'. This value
   should be unique in all csN classes.

   ct_encoding

   Specifies a list of encoding information that can be used for
   Compound Text.

Sample of X Locale Database

   The following is sample X Locale Database file.
#  XLocale Database Sample for ja_JP.euc
#

#
#      XLC_FONTSET category
#
XLC_FONTSET
#      fs0 class (7 bit ASCII)
fs0     {
        charset              ISO8859-1:GL
        font                 ISO8859-1:GL; JISX0201.1976-0:GL
}
#      fs1 class (Kanji)
fs1     {
        charset              JISX0208.1983-0:GL
        font                 JISX0208.1983-0:GL
}
#      fs2 class (Half Kana)
fs2     {
        charset              JISX0201.1976-0:GR
        font                 JISX0201.1976-0:GR
}
#      fs3 class (User Defined Character)
# fs3     {
#        charset             JISX0212.1990-0:GL
#        font                JISX0212.1990-0:GL
# }
END XLC_FONTSET

#
#      XLC_XLOCALE category
#
XLC_XLOCALE

encoding_name             ja.euc
mb_cur_max                3
state_depend_encoding     False

wc_encoding_mask          \x00008080
wc_shift_bits             8

#      cs0 class
cs0     {
        side                 GL:Default
        length               1
        wc_encoding          \x00000000
        ct_encoding          ISO8859-1:GL; JISX0201.1976-0:GL
}
#      cs1 class
cs1     {
        side                 GR:Default
        length               2

        wc_encoding          \x00008080

        ct_encoding          JISX0208.1983-0:GL; JISX0208.1983-0:GR;\
                             JISX0208.1983-1:GL; JISX0208.1983-1:GR
}

#      cs2 class
cs2     {
        side                 GR
        length               1
        mb_encoding          <SS> \x8e

        wc_encoding          \x00000080

        ct_encoding          JISX0201.1976-0:GR
}

#      cs3 class
# cs3     {
#         side               GL
#         length             2
#         mb_encoding        <SS> \x8f
# #if HasWChar32
#         wc_encoding        \x20000000
# #else
#         wc_encoding        \x00008000
# #endif
#         ct_encoding        JISX0212.1990-0:GL; JISX0212.1990-0:GR
# }

END XLC_XLOCALE

Reference

   [1] ISO/IEC 9899:1990 C Language Standard

   [2] X Logical Font Description Conventions
