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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.

       • 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>.

Version	1.8.4			Mon Sep	25 2023			 mdbGeneral(5)

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