mdbGeneral(5)							 The m17n Library						     mdbGeneral(5)

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.

       o 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.
       o SYMBOL
       An element that matches the regular expression [^-0-9(]([^()]|.)+ represents a property whose key is  Msymbol. In the element, 	, 
,
       
, 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'.
       o 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.
       o 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>.

Version 1.6.2							    12 Jan 2011 						     mdbGeneral(5)