# X Locale Database Specification

### Yoshio Horiuchi

IBM Japan

X Version 11, Release 7.7

Copyright © 1994 IBM Corporation

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# Chapter 1. LocaleDB

## 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