NAME

       mdbGeneral - General Format

DESCRIPTION

       The mdatabase_load() function returns the data specified by tags in the form of plist if
       the first tag is not Mchartable nor Mcharset. The keys of the returned plist are limited
       to Minteger, Msymbol, Mtext, and Mplist. The type of the value is unambiguously determined
       by the corresponding key. If the key is Minteger, the value is an integer. If the key is
       Msymbol, the value is a symbol. And so on.

       A number of expressions are possible to represent a plist. For instance, we can use the
       form (K1:V1, K2:V2, ..., Kn:Vn) to represent a plist whose first property key and value
       are K1 and V1, second key and value are K2 and V2, and so on. However, we can use a
       simpler expression here because the types of plists used in the m17n database are fairly
       restricted.

       Hereafter, we use an expression, which is similar to S-expression, to represent a plist.
       (Actually, the default database loader of the m17n library is designed to read data files
       written in this expression.)

       The expression consists of one or more elements. Each element represents a property, i.e.
       a single element of a plist.

       Elements are separated by one or more whitespaces, i.e. a space (code 32), a tab (code 9),
       or a newline (code 10). Comments begin with a semicolon (;) and extend to the end of the
       line.

       The key and the value of each property are determined based on the type of the element as
       explained below.

       • INTEGER
       An element that matches the regular expression -?[0-9]+ or 0[xX][0-9A-Fa-f]+ represents a
       property whose key is Minteger. An element matching the former expression is interpreted
       as an integer in decimal notation, and one matching the latter is interpreted as an
       integer in hexadecimal notation. The value of the property is the result of
       interpretation.
       For instance, the element 0xA0 represents a property whose value is 160 in decimal.
       • SYMBOL
       An element that matches the regular expression [^-0-9(]([^\()]|\.)+ represents a property
       whose key is  Msymbol. In the element, \t, \n, \r, and \e are replaced with tab (code 9),
       newline (code 10), carriage return (code 13), and escape (code 27) respectively. Other
       characters following a backslash is interpreted as it is. The value of the property is the
       symbol having the resulting string as its name.
       For instance, the element abc\ def represents a property whose value is the symbol having
       the name 'abc def'.
       • MTEXT
       An element that matches the regular expression '([^']|\')*' represents a property whose
       key is Mtext. The backslash escape explained above also applies here. r, each part in the
       element matching the regular expression  \[xX][0-9A-Fa-f][0-9A-Fa-f] is replaced with its
       hexadecimal interpretation.
       After having resolved the backslash escapes, the byte sequence between the double quotes
       is interpreted as a UTF-8 sequence and decoded into an M-text. This M-text is the value of
       the property.
       • PLIST
       Zero or more elements surrounded by a pair of parentheses represent a property whose key
       is Mplist. Whitespaces before and after a parenthesis can be omitted. The value of the
       property is a plist, which is the result of recursive interpretation of the elements
       between the parentheses.

SYNTAX NOTATION

       In an explanation of a plist format of data, a BNF-like notation is used. In the notation,
       non-terminals are represented by a string of uppercase letters (including '-' in the
       middle), terminals are represented by a string surrounded by '"'. Special non-terminals
       INTEGER, SYMBOL, MTEXT and PLIST represents property integer, symbol, M-text, or plist
       respectively.

EXAMPLE

       Here is an example of database data that is read into a plist of this simple format:
       DATA-FORMAT ::=
           [ INTEGER | SYMBOL | MTEXT | FUNC ] *

       FUNC ::=
           '(' FUNC-NAME FUNC-ARG * ')'

       FUNC-NAME ::=
           SYMBOL

       FUNC-ARG ::=
           INTEGER | SYMBOL | MTEXT | '(' FUNC-ARG ')'
       For instance, a data file that contains this text matches the above syntax:
       abc 123 (pqr 0xff) "m
       and is read into this plist:
       1st element: key: Msymbol,  value: abc
       2nd element: key: Minteger, value: 123
       3rd element: key: Mplist,   value: a plist of these elements:
           1st element: key Msymbol,  value: pgr
           2nd element: key Minteger, value: 255
       4th element: key: Mtext,    value: m"text
       5th element: key: Mplist,   value: a plist of these elements:
           1st element: key: Msymbol, value: __
           2nd element: key: Mplist,  value: a plist of these elements:
               1st element: key: Mtext,    value: string
            2nd element: key: Msymbol,  value: xyz
            3rd element: key: Minteger, value: -456

COPYRIGHT

       Copyright (C) 2001 Information-technology Promotion Agency (IPA)
       Copyright (C) 2001-2011 National Institute of Advanced Industrial Science and Technology
       (AIST)
       Permission is granted to copy, distribute and/or modify this document under the terms of
       the GNU Free Documentation License <http://www.gnu.org/licenses/fdl.html>.