Liblouisutdml User's and Programmer's Manual
1 Introduction
2 Transcribing Documents
  2.1 Transcribing XML files with file2brl
  2.2 Transcribing Text Documents
  2.3 Transcribing Poorly Formatted Documents
  2.4 Transcribing html Documents
3 Customization: Configuring liblouisutdml
  3.1 outputFormat
  3.2 translation
  3.3 xml
  3.4 style
    3.4.1 style document
    3.4.2 style contentsheader
    3.4.3 style contents1
    3.4.4 style contents2
    3.4.5 style contents3
    3.4.6 style contents4
    3.4.7 style heading1
    3.4.8 style heading2
    3.4.9 style heading3
    3.4.10 style heading4
    3.4.11 style para
    3.4.12 style boxline
4 Connecting with the xml Document - Semantic-Action Files
  4.1 Overview
  4.2 Semantic Actions in detail
  4.3 Pseudo-actions
    4.3.1 include
    4.3.2 newentries
    4.3.3 namespaces
  4.4 Using XPath Expressions
  4.5 Using Macros
5 Special Features
  5.1 Table of contents
  5.2 Back-translation
  5.3 Reformatting
  5.4 Interlining
  5.5 Browser-Friendly Output
  5.6 ‘CDATA’ Sections
  5.7 End notes
    5.7.1 Use of Endnotes
    5.7.2 Output
    5.7.3 Configuration
    5.7.4 Styles
    5.7.5 Semantic Actions
    5.7.6 Example
      5.7.6.1 input.xml
      5.7.6.2 liblouisutdml.ini
      5.7.6.3 endnotes.sem
      5.7.6.4 styles.cfg
      5.7.6.5 output.txt
6 Special Formats
  6.1 Tables
  6.2 Reserving Space for Graphics
  6.3 Displayed Text
  6.4 Displayed Mathematics
  6.5 Spatial Layouts in Mathematics
  6.6 Arithmetic Examples
  6.7 Poetry
  6.8 Dividing a Book Into Volumes
7 Implementing Braille Mathematics Codes
8 Programming with liblouisutdml
  8.1 License
  8.2 Overview
  8.3 Files and Paths
  8.4 lbu_version
  8.5 lbu_initialize
  8.6 lbu_translateString
  8.7 lbu_translateFile
  8.8 lbu_translateTextFile
  8.9 lbu_backTranslateFile
  8.10 lbu_free
Appendix A Example files
Configuration Settings Index
Semantic Action Index
Style Index
Function Index
Program Index
Concept Index
Liblouisutdml User's and Programmer's Manual
********************************************

This manual is for liblouisutdml (version 2.12.0, 2 November 2023), an
xml to Braille Translation Library.

   This file may contain code borrowed from the Linux screenreader
BRLTTY, Copyright © 1999-2009 by the BRLTTY Team.

Copyright © 2004-2009 ViewPlus Technologies, Inc.  <www.viewplus.com>
and Copyright © 2006,2009 Abilitiessoft, Inc.  <www.abilitiessoft.org>.

     This file is free software; you can redistribute it and/or modify
     it under the terms of the GNU Lesser (or library) General Public
     License (LGPL) as published by the Free Software Foundation; either
     version 3, or (at your option) any later version.

     This file is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
     Lesser (or Library) General Public License LGPL for more details.

     You should have received a copy of the GNU Lesser (or Library)
     General Public License (LGPL) along with this program; see the file
     COPYING. If not, write to the Free Software Foundation, 51 Franklin
     Street, Fifth Floor, Boston, MA 02110-1301, USA.

1 Introduction
**************

liblouisutdml is a software component which can be incorporated into
software packages to provide the capability of translating any file in
the computer lingua franca xml format or plain text into properly
transcribed braille.  This includes translation into grade two, if
desired, mathematical codes, etc.  It also includes formatting according
to a style sheet which can be modified by the user.  The first program
into which liblouisutdml has been incorporated is ‘file2brl’.  This
program will translate an xml or text file into an embosser-ready
braille file.  It is not necessary to know xml, because MSWord and other
word processors can export files in this format.  If the word processor
has been used correctly ‘file2brl’ will produce an excellent braille
file.

   Users who want to generate Braille using ‘file2brl’ will be
interested in *note Transcribing XML files with file2brl::.  Those who
wish to change the output generated by liblouisutdml should read *note
Customization Configuring liblouisutdml::.  If you encounter a type of
xml file with which liblouisutdml is not familiar you can learn how to
tell it how to process that file by reading *note Connecting with the
xml Document::.  If you wish to implement a new braille mathematics code
read *note Implementing Braille Mathematics Codes::.  Finally, computer
programmers who wish to use liblouisutdml in their software can find the
information they need in *note Programming with liblouisutdml::.

   You will also find it advantageous to be acquainted with the
companion library liblouis, which is a braille translator and
back-translator (*note Overview: (liblouis)Top.).

2 Transcribing Documents
************************

2.1 Transcribing XML files with file2brl
========================================

At the moment, actual transcription with liblouisutdml is done with the
command-line (or console) program ‘file2brl’.  The line to type is:

     file2brl [OPTIONS] [-f config-file] [infile] [outfile]

   The brackets indicate that something is optional.  You will see that
nothing is required except the program name itself, ‘file2brl’.  The
various optional parts control how the program will behave, as follows:

‘-h’
‘--help’
     This option causes ‘file2brl’ to print a help message describing
     usage and exit.

‘-v’
‘--version’
     This option causes ‘file2brl’ to display the version information
     and exit.

‘-f configfile’
‘--config-file configfile’
     This specifies the configuration file which tells ‘file2brl’ how to
     do the transcription.  (It may be a list of file names separated by
     commas.)  This file specifies such things as the number of cells
     per line, the number of lines per page, The translation tables to
     be used, how paragraphs and headings are to be formatted, etc.  If
     this part of the command line is omitted, ‘file2brl’ assumes that
     the configuration file is named ‘preferences.cfg’.  If the
     configuration file name contains a pathname ‘file2brl’ will
     consider this as a path on which to look for files that it needs
     (*note Files and Paths::).  If no pathname is given the standard
     paths are searched and finally the current directory.  To make
     ‘file2brl’ search the current directory first, precede the file
     name with ‘./’.

‘-b’
‘--backward’
     back-translate.  The input file must be a braille file, such as
     ‘.brf’.  The output file is a back-translation of this file.  It
     may be in either plain-text or xhtml (html), according to the
     setting of ‘backFormat’ in the ‘outputFormat’ section of the
     configuration file.  Html files will contain page numbers and
     emphasis.  To get good html, the liblouis table must have the entry
     ‘space \e 1b’ so that it will pass through escape characters.  The
     ‘html.sem’ file must also contain the line ‘pagenum pagenum’.  Text
     output files simply have a blank line between paragraphs.  Encoding
     of text files is controlled by the ‘outputEncoding’ setting.  Html
     files are always in UTF-8.

‘-r’
‘--reformat’
     Reformat.  The input file must be a braille file, such as ‘.brf’.
     The output is a braille file formatted according to the
     configuration file.  It is advisable to set backFormat to html,
     since this will preserve print page numbers and emphasis.  This
     option can be useful for changing the line length and page length
     of a braille file, for example, from 40 to 32 cells.  It is also an
     excellent way to check the accuracy of liblouis tables.  The
     original page numbers at the tops and bottoms of pages are
     discarded, and new ones are generated.

‘-T’
‘--text’
     Consider the document to be a text file, even if it is xml or html.

‘-t’
‘--html’
     The document is an h(t)ml file, not xhtml.  This option is useful
     with files downloaded from the Web in source form.  Without it, the
     program will first try to parse the file as an xml document,
     producing lots of error messages.  It will then try the html
     parser.  With this option, it goes directly to the html parser.
     See also the ‘formatFor’ configuration (*note formatFor setting::)
     file setting, which enables you to format the braille output for
     viewing in a browser.

‘-p’
‘--poorly-formatted’
     Poorly formatted input translation.  Infile is any text file such
     as may have been obtained by extracting the text in a pdf file.
     The input file may also be an xml or html file which is so poorly
     formatted that better braille can be obtained by ignoring the
     formatting.  ‘file2brl’ tries to guess paragraph breaks.  The
     output is generally reasonably formatted, that is, with reasonable
     paragraph breaks.

‘-P’
‘--paragraph-line’
     Treat each block of text ending in a newline as a paragraph.  If
     there are two newline characters a blank line will be inserted
     before the next paragraph.

‘-Csetting=value’
‘--config-setting setting=value’
     This option enables you to specify configuration settings on the
     command line instead of changing the configuration file.  You can
     use as many ‘-C’ options as you wish.  Any settings can be
     specified except those having to do with styles.  *Note
     Configuration Settings Index::, for a list of available settings.
     These must be specified in configuration files.  The settings may
     be in any order.  They override any settings in ‘liblouisutdml.ini’
     or in the configuration file used by ‘file2brl’.

‘-w’
‘--writeable-path’
     This option enables you to specify where the log file and other
     temporary files will be written.

‘-l’
‘--log-file’
     This option will cause ‘file2brl’ and liblouisutdml to print error
     messages to ‘file2brl.log’ instead of stderr.  The file will be in
     the current directory.  This option is particularly useful if
     ‘file2brl’ is called by a GUI script or Web application.

‘infile’
     This is the name of the input file containing the material to be
     transcribed.  The file may be either an xml file or a text file.
     The ‘-b’, ‘-r’ and ‘-p’ options discussed above provide for other
     types of files and processing.  Typical xml files are those
     provided by <www.bookshare.org> or those derived from a word
     processor by saving in xml format.  If a text file is used,
     paragraphs and headings should be separated by blank lines.  In
     such a file there is no way to distinguish between paragraphs and
     headings, so they will all be formatted as paragraphs, as specified
     by the configuration file.  However, if you want a blank line in
     the braille transcription, use two consecutive blank lines in the
     text file.

‘outfile’
     This is the name of the output file.  It will be transcribed as
     specified by the configuration file and the ‘-C’ configuration
     settings.  The following paragraphs provide more information on
     both the input and output files.

   ‘file2brl’ is set up so that it can be used in a "pipe".  To do this,
omit both infile and outfile.  Input is then taken from the standard
input unit.

   The first file name encountered (a word not preceded by a minus sign)
is taken to be the input file and the second to be the output file.  If
you wish input to be taken from stdin and still want to specify an
output file, use one minus sign (‘-’) for the input file.

   If only the program name is typed ‘file2brl’ assumes that the
configuration file is ‘preferences.cfg’, input is from the standard
input unit, and output is to the standard output unit.

2.2 Transcribing Text Documents
===============================

See the previous section on using ‘file2brl’.  This program recognizes
text files automatically and transcribes them according to the
information in the configuration files.  Paragraphs must be separated
with a blank line.  If you want a blank line in the output use two blank
lines.

2.3 Transcribing Poorly Formatted Documents
===========================================

     file2brl -p infile outfile

   Some text documents, such as those derived from pdf files, and even
some xml and html documents, are so poorly formatted that you can get
better braille by ignoring whatever markup they contain.  The ‘-p’
option of ‘file2brl’ does this.  It ignores xml or html markup and uses
heuristics to find the beginning of paragraphs.  Its choices are usually
good.  Note that it does not work with rtf files.

2.4 Transcribing html Documents
===============================

     file2brl -t infile outfile

   The ‘-t’ option prevents ‘file2brl’ from trying to transcribe infile
as an xml document.  This will produce a lot of error messages.
‘file2brl’ will then try the html parser.  Note that xhtml documents are
actually xml.

3 Customization: Configuring liblouisutdml
******************************************

The operation of liblouisutdml is controlled by two types of files:
semantic-action files and configuration files.  The former are discussed
in the section Connecting with the xml Document - Semantic-action Files
(*note Connecting with the xml Document - Semantic-Action Files:
Connecting with the xml Document.).  The latter are discussed in this
section.  A third type of file, braille translation tables, is discussed
in the liblouis documentation (*note Overview: (liblouis)Top.).

   Another section of the present document which may be of interest is
Implementing Braille Mathematical Codes (*note Implementing Braille
Mathematics Codes::).

   Besides files, liblouisutdml can also be controlled by configuration
strings, which are character strings in memory containing configuration
settings separated by end-of-line characters.  Such strings can be
generated by the ‘-C’ option on the ‘file2brl’ command line, by the
‘configstring’ and ‘configtweak’ semantic actions, or by passing a
string to the ‘lbu_initialize’ function.

   The information below applies to ‘file2brl’ as much as to
liblouisutdml.

   Before discussing configuration files in detail it is worth noting
that the application program has access to the information in the
configuration files by calling the liblouisutdml function
‘lbu_initialize’.  This function returns a pointer to a data structure
containing the configuration information.  The calling program must
include the header file ‘louisutdml.h’.  You do not need to call
‘lbu_initialize’ unless you need the facilities which it provides.

   A configuration file specification may contain more than one file
name, separated by commas.  liblouisutdml will process these files in
sequence, merging the information they contain.  The first file name may
also contain a path.  liblouisutdml will search for the files it needs
first on this path.  To make it search first the current directory
precede the first file name with ‘./’.  After the path, if any, has been
evaluated, but before reading any of the files, liblouisutdml reads in a
file called ‘liblouisutdml.ini’.  This file can contain any
configuration settings, but it usually contains only the minimum ones
for liblouisutdml to operate properly.  You may alter the values in the
distribution ‘liblouisutdml.ini’, but you should not delete any
settings.  Do not specify ‘liblouisutdml.ini’ as your configuration
file.  This will lead to error messages and program termination.  If a
configuration file read in later contains a particular setting name, the
value specified simply replaces the one specified in ‘liblouisutdml.ini’
or any previously read configuration file.

   Originally, configuration files contained four main sections,
‘outputFormat’, ‘translation’, ‘xml’ and ‘style’.  The section names,
except for ‘style’ are now optional.  In addition, a configuration file
can contain an include entry.  This causes the file named on that line
to be read in at the point where the line occurs.  The sections need not
follow each other in any particular order, nor is the order of settings
within each section important.  The section names, except for ‘style’
are optional.  In this document and in the ‘liblouisutdml.ini’ file,
where section and setting names consist of more than one word, the first
letter of each word following the initial one is capitalized.  This is
merely for readability.  The case of the letters in these names is
ignored by the program.  Section and setting names may not contain
spaces.

   In addition to ‘liblouisutdml.ini’ the distribution also contains a
number of configuration files.  The most important of these is
‘preferences.cfg’, which contains all possible settings and a "default"
value for each.  You should use this file as a reference.  It is the
file read by the ‘file2brl’ command-line interface program if no
configuration file is given.

   Here, then, is an explanation of each section and setting in the
‘preferences.cfg’ file.  When you look at this file you will see that
the section names start at the left margin, while the settings are
indented one tab stop.  This is done for readability, it has no effect
on the meaning of the lines.  You will also see lines beginning with a
number sign (‘#’), which are comments.  Blank lines can also be used
anywhere in a configuration file.  In general, a section name is a
single word or combination of unspaced words.  However, each style has a
section of its own, so the word ‘style’ is followed by a space then by
the name of the style.  Setting lines begin with the name of the
setting, followed by at least one space or tab, followed by the value of
the setting.  A few settings have two values.

3.1 outputFormat
================

This section specifies the format of the output file (or string).

‘cellsPerLine 40’
     The number of cells in a braille line.

‘linesPerPage 25’
     The number of lines on a braille page

‘interpoint no’
     Whether or not the output will be used to produce interpoint
     braille.  This affects the placement of page numbers and may affect
     other things in the future.  The only two values recognized are
     ‘yes’ and ‘no’.

‘lineEnd \r\n’
     This specifies the control characters to be placed at the end of
     each output line.  These characters vary from one intended use of
     the output to another.  Most embossers require the carriage-return
     and line-feed combination specified above.  However, a braille
     display may work best with just one or the other.  Any valid
     control characters can be specified.

‘pageEnd \f’
     The control Character to be given at the end of a page.  Here it is
     a forms-feed character, but it can be something else if deeded.

‘fileEnd ^z’
     The control character to be placed at the end of the file, here a
     control-z.

‘printPages yes’
     Whether or not to show print page numbers if they are given in the
     xml input.  The two valid values are ‘yes’ and ‘no’.

‘braillePages yes’
     Whether or not to format the output into pages.  Here the value is
     ‘yes’, for use with an embosser.  However the user of a braille
     display may wish to specify ‘no’, so as not to be bothered with
     page numbers and forms feed characters.  If no is specified the
     lines will still be of the length given in ‘cellsPerLine’, but the
     value of ‘linesPerPage’ will be ignored.

‘paragraphs yes’
     Whether or not to format the output into paragraphs, using
     appropriate styles.  If ‘no’ is specified, what would be a
     paragraph is output simply as one long line.  Applications that
     wish to do their own formatting may specify ‘no’.

‘beginningPageNumber 1’
     This is the number to be placed on the first Braille page if
     ‘braillePages’ is yes.  This is useful when producing multiple
     Braille volumes.

‘printPageNumberAt top’
     If print page numbers are given in the xml input file they will be
     placed at the top of each braille page in the right-hand corner.
     If ‘pageSeparator’ is set to ‘yes’, a page separator line will also
     be produced on the Braille page where the print page break actually
     occurs.  You may also specify ‘bottom’ for this setting.

‘braillePageNumberAt bottom’
     The braille page number will be placed in the bottom right-hand
     corner of each page.  If ‘interpoint yes’ has been specified only
     odd pages will receive page numbers.  You may also specify ‘top’
     for this setting.  If print page numbers and Braille page numbers
     are both placed at the top or bottom, they are rendered next to
     each other with a space in between.

‘continuePages yes’
     Print page numbers can be prefixed with a letter (a, b, c, etc.)
     on continued pages.  The two valid values are ‘yes’ and ‘no’.

‘pageSeparator yes’
     A page separator line (or page break indicator), a line of unspaced
     Braille dots 36, will be placed wherever a print page break occurs.
     No page separator lines are placed on the first or last line of a
     Braille page, and no page separator lines are shown when the new
     print page coincides with a new Braille page.

‘pageSeparatorNumber yes’
     Show a page number at the far right margin of a page separator
     line.  No space is left between the separator line and the first
     symbol of the page number.

‘ignoreEmptyPages yes’
     An empty page occurs when a ‘pagenum’ tag is immediately followed
     by another ‘pagenum’ tag.  By default, empty pages are completely
     ignored.  If you specify ‘no’ for this setting, a sequence of
     ‘pagenum’ tags will lead to a _combined_ print page number: the
     number of the first empty page is combined with that of the page on
     which text reappears, e.g.  5-7.  If lettered continuation pages
     are required (see ‘continuePages’), they carry only the number of
     the page on which text reappears.

‘printPageNumberRange no’
     By default, only the page number of the _first_ print page on a
     Braille page is shown at the top or bottom.  However, if
     ‘printPageNumberRange’ is set to ‘yes’, the _range_ of print pages
     contained in the current Braille page is displayed.  If the first
     page in this range is a continued print page, it is prefixed with a
     letter as usual (see ‘continuePages’).

‘mergeUnnumberedPages yes’
     Page breaks without a page number can simply be ignored.  This
     means that unnumbered print pages will be treated as if they were a
     part of the preceding page.  You can also specify ‘no’ for this
     setting.

‘pageNumberTopSeparateLine yes’
     Whether or not to provide a separate line for page numbers when
     they are placed at the top of a Braille page.  The two valid values
     are ‘yes’ and ‘no’.  A print page number range (see
     ‘printPageNumberRange’) at the top of a page is always displayed on
     a separate line.

‘pageNumberBottomSeparateLine yes’
     Whether or not to provide a separate line for page numbers when
     they are placed at the bottom of a Braille page.

‘hyphenate no’
     If ‘yes’ is specified words will be hyphenated at the ends of lines
     if a hyphenation table is available.  In contracted English
     Braille, hyphenation is not generally used, but it can save
     considerable space.  The hyphenation table is specified as part of
     the table list in the ‘literaryTextTable’ setting of the
     translation section.

‘outputEncoding ascii8’
     This specifies that the output is to be in the form of 8-bit ASCII
     characters.  This is generally used if the output is intended
     directly for a braille embosser or display.  The other values of
     encoding are ‘UTF8’, ‘UTF16’ and ‘UTF32’.  These are useful if the
     application will process the output further, such as for generating
     displays of braille dots on a screen.

‘inputTextEncoding ascii8’
     This setting is used to specify the encoding of an input text file.
     The valid values are ‘UTF8’ and ‘ascii8’.

‘formatFor textDevice’
     This setting specifies the type of device the output is intended
     for.  ‘textDevice’ is any device that accepts plain text, including
     embossers.  You can also specify ‘browser’.  In this case the
     output will be formatted for viewing in a browser.  If the input
     file contains links, they will be preserved and can be used in the
     normal way.  The text will be translated into braille with the
     correct line length.  Math and computer material will be translated
     appropriately.  These files work well in lynx and Internet
     Explorer, not so well in elinks and Firefox (Before Jaws 10).

‘backFormat plain’
     This setting specifies the format of back-translated files.
     ‘Plain’ specifies plain-text, while ‘html’ specifies xhtml.  The
     latter is always encoded in UTF-8.  Plain-text files can be encoded
     in ascii8, UTF-8 or UTF-16.  Html is strongly recommended, since it
     will preserve print page numbering and emphasis.

‘backLineLength 70’
     This setting specifies the length of lines in back-translated
     files, whether in plain-text or html.  This is mainly for human
     readability.  Lines may sometimes be somewhat longer.

‘lineFill '’
     This setting defines the fill character that will be used before
     the page numbers in the table of contents for example.  The default
     fill character is an apostrophe (dot 3).

3.2 translation
===============

This section specifies the liblouis translation tables to be used for
various purposes.

‘literaryTextTable en-us-g2.ctb’
     The table used for producing literary braille.  This may be either
     contracted or uncontracted.

‘uncontractedTable en-us-g1.ctb’
     The table used for producing uncontracted or Grade One braille.
     This setting appears to be superfluous and may be eliminated in the
     future.

‘compbrailleTable en-us-compbrl.ctb’
     The table used for producing large amounts of output in computer
     braille, such as computer programs.  The computer braille table is
     usually combined with one of the two tables above.

‘mathtextTable en-us-mathtext.ctb’
     This table specifies how the non-mathematical parts of math books
     are to be translated.  In many cases it will be the same as
     literaryTextTable or uncontractedTable.  For books translated with
     the Nemeth Code it is different, because this code requires
     modification of standard Grade Two.

‘MathexpTable nemeth.ctb’
     This is the table used to translate mathematical expressions.

‘editTable nemeth_edit.ctb’
     When the output includes both mathematics and text there may be
     errors where one type of translation directly follows another.  The
     editTable removes these errors.

3.3 xml
=======

This section provides various information for the processing of xml
files.

‘semanticFiles *,nemeth.sem’
     This setting gives a list of semantic-action files.  These files
     are read in the sequence given in the list.  Here the first member
     of the list is an asterisk (‘*’).  This means that the
     corresponding file is to be named by taking the root element of the
     document and appending ‘.sem’.  This asterisk member may occur
     anywhere in the list.

‘xmlheader <?xml version='1.0' encoding='UTF8' standalone='yes'?>’
     This line gives the xml header to be added to strings produced by
     programs like ‘Mathtype’ that lack one.

‘entity nbsp ^1’
     This line defines an entity or substitution in an xml file.  It is
     one of those that has two values.  The first is the thing to be
     replaced, and the second is the replacement.  As many entity lines
     as necessary can be used.  The information they contain is added to
     the information provided by xmlHeader.  In ‘liblouisutdml.ini’ this
     line is commented out, because specifying it at this point would
     prevent the user from specifying his own xmlheader.

‘internetAccess yes’
     The computer has an internet connection and liblouisutdml may
     obtain information necessary for the processing of this file from
     the Internet.  If this setting is ‘no’ liblouisutdml will not try
     to use the internet.  The necessary information may, however, be
     provided on the local machine in the form of a "dtd" file.

‘newEntries yes’
     liblouisutdml may create a new semantic-action file (beginning with
     ‘new_’) for a document with an unknown root element or a file
     (beginning with ‘appended_’) containing new entries for an existing
     semantic-action file.  Both kinds of files are placed on the
     current directory.  If this setting is ‘no’ liblouisutdml will not
     create a file of new entries and if it encounters a document with
     an unknown root element it will issue an error message.  Setting
     newEntries to ‘no’ may be useful if users should not be bothered
     with the minutiae of semantic-action files.

3.4 style
=========

The following sections all deal with styles.  Each style has its own
section.  Style section names are unlike other section names in that
they consist of the word style, followed by a space, followed by a style
name.  With some exceptions, styles are not hard-coded.  The user may
define any style desired, with any name except ‘document’, ‘para’,
‘heading1’, ‘heading2’, ‘heading3’, ‘heading4’, ‘contentsheader’,
‘contents1’, ‘contents2’, ‘contents3’ and ‘contents4’.  The first two
are needed for basic formatting.  The others are needed for the table of
contents tool.  The user must define settings for these styles as for
any others.  This is done in ‘liblouisutdml.ini’, which also contains
definitions and settings for many other styles.  The user can add styles
at any time in her/his own configuration files.

   Styles can be nested.  That is, a document may contain a section of
one style, and inside this may be a section of another style.  For
example, you might have styles named frontMatter, titlePage, dedication,
contents, and so on.  Your document might contain a section of style
frontMatter.  Inside this section might be subsections of styles
titlePage, dedication, contents, and so on.  Inside the titlePage
section there might be other sections with styles heading1, para,
centered, etc.

   Your frontMatter style might also define the "persistent" style
setting ‘braillePageNumberFormat roman’.  This setting will apply to all
the styles nested within frontMatter, unless they have a setting other
than ‘normal’, which is the default and means ordinary braille page
numbers.  However, the titlePage style might have the setting
‘braillePageNumberFormat blank’.  This will apply to all styles nested
within it.  When the titlePage section ends, the frontMatter setting
‘roman’ will be restored.  The ‘braillePageNumberFormat’ setting is an
example of a "persistent" style setting.  Most settings apply only to
the style for which they are declared.

   Below are the settings for the predefined style names.  The
‘document’ style contains all possible settings.  The others contain
only settings that are different from the defaults.

3.4.1 style document
--------------------

This is a predefined style name.  All settings have their default
values.  The user must specify any other values.  If a "persistent"
style setting is specified, it will apply to the whole document.

‘linesBefore 0’

     This setting gives the number of blank lines which should be left
     before the text to which this style applies.  It is set to a
     non-zero value for some header styles.

‘linesAfter 0’

     The number of blank lines which should be left after the text to
     which this style applies.

‘leftMargin 0’

     The number of cells by which the left margin of all lines in the
     text should be indented.  Used for hanging indents, among other
     things.  This is a "persistent" setting, so by default all nested
     styles will inherit the setting.

‘rightMargin 0’

     The equivalent of ‘leftMargin’ for the right side of the page.
     This is also a persistent setting.

‘firstLineIndent 0’

     The number of cells by which the first line is to be indented
     relative to leftMargin.  firstLineIndent may be negative.  If the
     result is less than 0 it will be set to 0.  This setting is
     persistent.

‘translate contracted’

     This setting is currently inactive.  It may be used in the future.
     This setting tells how text in this style should be translated.
     Possible values are ‘contracted’, ‘uncontracted’, ‘compbrl’,
     ‘mathtext’ and ‘mathexpr’.

‘skipNumberLines no’

     If this setting is ‘yes’ the top and bottom lines on the page will
     be skipped if they contain braille or print page numbers.  This is
     useful in some of the mathematical and graphical styles.

‘format leftJustified’

     The format setting controls how the text in the style will be
     formatted.  Valid values are ‘leftJustified’, ‘rightJustified’,
     ‘centered’, ‘computerCoded’, ‘alignColumnsLeft’,
     ‘alignColumnsRight’, and ‘contents’.  The first three are
     self-explanatory.  ‘computerCoded’ is used for computer programs
     and similar material.  The next two are used for tabular material.
     ‘alignColumnsLeft’ causes the left ends of columns to be aligned.
     ‘alignColumnsRight’ causes the right ends of columns to be aligned.
     ‘contents’ is used only in styles specifically intended for tables
     of contents.  In the case of ‘leftJustified’, ‘rightJustified’ and
     ‘centered’, nested styles inherit this setting by default.

‘newPageBefore no’

     If this setting is ‘yes’, the text will begin on a new page.  This
     is useful for certain mathematical and graphical styles.  Page
     numbers are handled properly.

‘newPageAfter no’

     If this setting is ‘yes’ any remaining space on the page after the
     material covered by this style is handled is left blank, except for
     page numbers.

‘rightHandPage no’

     if this setting is ‘yes’ and interpoint is yes the material covered
     by this style will start on a right-hand page.  This may cause a
     left-hand page to be left blank except for page numbers.  If
     interpoint is ‘no’ this setting is equivalent to newPageBefore.

‘braillePageNumberFormat normal’

     This setting specifies the format of braille page numbers.
     ‘normal’ means ordinary Arabic numbers.  ‘roman’ means Roman
     numbers.  ‘p’ means to precede Arabic numbers with the letter "p"
     (for preliminary).  Finally, ‘blank’ causes the page number to be
     blank (no page numbers).  This is a "persistent" style setting.

‘dontSplit no’

     If this setting is ‘yes’, the element is protected from being split
     across pages.  This means that if a block of text doesn't fit on
     the current page, it will be placed at the beginning of the next
     one.  This setting applies to the whole element, including
     children, so if nested styles specify other values for ‘dontSplit’,
     these values will be ignored.

‘keepWithNext no’

     If this setting is ‘yes’, the element covered by this style is
     protected from being split across pages, and in addition it is kept
     together with the first line of text of the next sibling.

‘orphanControl 0’

     With this setting you can control how many lines of text of an
     element must be printed at least at the bottom of a braille page.
     The default value is ‘0’.  To have an effect, the setting must have
     a value of ‘2’ or more.

3.4.2 style contentsheader
--------------------------

This style is used to specify where the table of contents should be
placed and its title.  The xml tag assigned to it in the semantic action
file should be placed in the document where you want the table of
contents, and it should contain the title of that table between its
starting and ending markers.

‘linesBefore 1’
‘linesAfter 1’
‘format centered’

3.4.3 style contents1
---------------------

This style and the other contents styles are used for the table of
contents and correspond to the ten heading levels (‘contents5’,
‘contents6’, ‘contents7’, ‘contents8’, ‘contents9’ and ‘contents10’ are
not showed here).

‘firstLineIndent -2’
‘leftMargin 2’
‘format contents’

3.4.4 style contents2
---------------------

‘firstLineIndent -2’
‘leftMargin 4’
‘format contents’

3.4.5 style contents3
---------------------

‘firstLineIndent -2’
‘leftMargin 6’
‘format contents’

3.4.6 style contents4
---------------------

‘firstLineIndent -2’
‘leftMargin 8’
‘format contents’

3.4.7 style heading1
--------------------

This style is used for main headings, such as chapter titles.

‘linesBefore 1’
‘center yes’
‘linesAfter 1’

3.4.8 style heading2
--------------------

The first level of subheadings after the main heading.

‘linesBefore 1’
‘firstLineIndent 4’

3.4.9 style heading3
--------------------

The third level of headings.

‘firstLineIndent 4’

3.4.10 style heading4
---------------------

The fourth level of headings.  There are six more levels: ‘heading5’,
‘heading6’, ‘heading7’, ‘heading8’, ‘heading9’ and ‘heading10’.

‘firstLineIndent 4’

3.4.11 style para
-----------------

Paragraph.  This is ordinary body text.

‘firstLineIndent 2’

3.4.12 style boxline
--------------------

Typically used to form the top and bottom lines of "boxed" material.
The character must be chosen to produce the desired dot pattern on the
embosser or display in use.

‘topBoxline .’

     This should be set to the character you want to be used for the
     boxline which appears before the content.

‘bottomBoxline .’

     This should be set to the character you want to be used for the
     boxline which appears after the content.

4 Connecting with the xml Document - Semantic-Action Files
**********************************************************

4.1 Overview
============

When liblouisutdml (or ‘file2brl’) processes an xml document, it needs
to be told how to use the information in that document to produce a
properly translated and formatted braille document.  These instructions
are provided by a semantic-action file, called so because it explains
the meaning, or semantics, of the various specifications in the xml
document.  To understand how this works, it is necessary to have a basic
knowledge of the organization of an xml document.

   An xml document is organized like a book, but with much finer detail.
First there is the title of the whole book.  Then there are various
sections, such as author, copyright, table of contents, dedication,
acknowledgments, preface, various chapters, bibliography, index, and so
on.  Each chapter may be divided into sections, and these in turn can be
divided into subsections, subsubsections, etc.  In a book the parts have
names or titles distinguished by capitalization, type fonts, spacing,
and so forth.  In an xml document the names of the parts are enclosed in
angle brackets (‘<>’).  For example, if liblouisutdml encounters
‘’ at the beginning of a document, it knows it is dealing with a
document that conforms to the standards of the extensible markup
language (xhtml) - at least we hope it does.  When you see a book, you
know it's a book.  The computer can know only by being told.  Something
enclosed in angle brackets is called an "element" (more properly, a
"tag") in xml parlance.  (There may be more between the angle brackets
than just the name of the element.  More of this later).  The first
"element" in a document thus tells liblouisutdml what kind of document
it is dealing with.  This element is called the "root element" because
the document is visualized as branching out from it like a tree.  Some
examples of root elements are ‘’, ‘’, ‘<book>’, ‘<dtbook>’
and ‘<wordDocument>’.  Whenever liblouisutdml encounters a root element
that it doesn't know about it creates a new file called a
semantic-action file.  The name of this file is formed by stripping the
angle brackets from the root element, putting ‘new_’ in front of it and
adding a period plus the letters ‘sem’.  For example,
‘new_myformat.sem’.  If you look in a directory containing
semantic-action files you will see names like ‘html.sem’, ‘dtbook.sem’,
‘math.sem’, and so on.  The "new" semantic-action files must be edited
by a person and the prefix "new" removed to get an ordinary
semantic-action file name.

   Sometimes it is advantageous to preempt the creation of a
semantic-action file for a new root element.  For example, an article
written according to the docbook specification may have the root element
‘<article>’.  However, the specification itself has the root element
‘<book>’.  In this case you can specify the ‘book.sem’ file in the
configuration file by writing, in the xml section,:

     semanticFiles book.sem

   You will note that this setting uses the plural of "file".  This is
because you can actually specify a list of file names separated by
commas.  You might want to do this to specify the semantic-action file
for the particular braille mathematical code to be used.  For example:

     semanticFiles book.sem,ukmaths.sem

   You can use an asterisk ‘*’ to specify the semantic-action file
corresponding to the root element of the document anywhere in the list.

   As you will see in the next section, different braille style
conventions and different braille mathematical codes may require
different semantic-action files

   liblouisutdml records the names of all elements found in the document
in the semantic-action file.  The document has a multitude of elements,
which can be thought of as describing the headings of various parts of
the document.  One element is used to denote a chapter heading.  Another
is used to denote a paragraph, Still another to denote text in bold
type, and so on.  In other words, the elements take the place of the
capitalization, changes in type font, spacing, etc.  in a book.
However, the computer still does not know what to do when it encounters
an element.  The semantic-action file tells it that.

   Consider ‘html.sem’.  A copy is included as part of this
documentation with the name ‘example_html.sem’ (*note Example files::).
It may differ from the file that liblouisutdml is currently using.  You
will see that it begins with some lines about copyrights.  Each line
begins with a number sign (‘#’).  This indicates that it is a "comment",
intended for the human reader and the computer should ignore it.  Then
there is a blank line.  Finally, there are two other comments explaining
that the file must be edited to get proper output.  This is because a
human being must tell the computer what to do with each element.  The
semantic files for common types of documents have already been edited,
so you generally don't have to worry about this.  But if you encounter a
new type of document or wish to specify special handling for styles or
mathematics you may have to edit the semantic-action file or send it to
the maintainer for editing.  In any case the rest of this section is
essential for understanding how liblouisutdml handles documents and for
making changes if the way it does so is not correct.

   After another blank line you will see a table consisting of two, and
sometimes three, columns.  The first column contains a word which tells
the computer to do something.  For example, the first entry in the table
is: ‘include nemeth.sem’.  This tells liblouisutdml to include the
information in the ‘nemeth.sem’ file when it is deciphering an html
(actually xhtml) document (it may be preferable to use the semanticFiles
setting in the configuration file rather than an include).

   The second row of the table is:

     no hr

   ‘hr’ is an element with the angle brackets removed.  It means nothing
in itself.  However, the first column contains the word ‘no’.  This
tells liblouisutdml "no do", that is, do nothing.  This is not strictly
true, since liblouisutdml will sometimes insert a blank space so that
words in text do not run together.

   After a few more lines with ‘no’ in the first column, we see one that
says:

     softreturn br

   This means that when the element ‘
’ is encountered, liblouisutdml
is to do a soft return, that is, start a new line without starting a new
paragraph.

   The next line says:

     heading1 h1

   This tells liblouisutdml that when it encounters the element ‘<h1>’
it is to format the text which follows as a first-level braille heading,
that is, the text will be centered and preceded and followed by blank
lines.  (You can change this by changing the definition of the heading1
style).

   The next line says:

     italicx em

   This tells liblouisutdml that when it encounters the element ‘<em>’
it is to enclose the text which follows in braille italic indicators.
The ‘x’ at the end of the semantic action name is there to prevent
conflicts with names elsewhere in the software.  Just where the italic
indicators will be placed is controlled by the liblouis translation
table in use.

   The next line says:

     skip style

   This tells liblouis to simply skip ahead until it encounters the
element ‘’.  Nothing in between will have any effect on the
braille output.  Note the slash (‘/’) before the ‘style’.  This means
the end of whatever the ‘’ element was referring to.  Actually,
it was referring to specifications of how things should be printed.  If
liblouisutdml had not been told to skip these specifications, the
braille output would have contained a lot of gobledygook.

   The next line says:

     italicx strong

   This tells liblouis to also use the italic braille indicators for the
text between the ‘’ and ‘’ elements.

   After a few more lines with ‘no’ in the first column we come to the
line:

     document html

   This tells liblouisutdml that everything between ‘’ and
‘’ is an entire document.  ‘’ was the root element of this
document, so this is logical.

   After another ‘no’ line we come to:

     para p

   liblouisutdml will consider everything between ‘
’ and ‘
’ to be
a normal body text paragraph.

   The next line is:

     heading1 title

   this causes the title of the document to also be treated as a braille
level 1 heading.

   Next we have the line:

     list li

   The xhtml ‘
- ’ and ‘’ pair of elements is used to enclose an
item in a list.  liblouisutdml will format this with its own list style.
That is, the first line will begin at the left margin and subsequent
lines will be indented two cells.

   Next we have:

     table table

   You will note that the names of actions and elements are often
identical.  This is because they are both mnemonic.  In any case, this
line tells liblouisutdml to format the table contained in the xhtml
document according to the table formatting rules it has been given for
braille output.

   Next we have the line:

     heading2 h2

   This means that the text between ‘
’ and ‘
’ is to be
formatted according to the Liblouisutdml style heading2.  A blank line
will be left before the heading and the first line will be indented four
spaces.

   After a few more lines we come to:

     no table,cellpadding

   Note the comma in the second column.  This divides the column into
two subcolumns.  The first is the table element name.  The second is
called an "attribute" in xml.  It gives further instructions about the
material enclosed between the starting and ending "tags" of the element
(‘
’ and ‘
’.  Full information requires three subcolumns.
The third is called the value and gives the actual information.  The
attribute is merely the name of the information.

   Much further down we find:

     no table,border,0

   Here the element is table, the attribute is border and the value is
0.  If liblouisutdml were to interpret this, it would mean that the
table was to have a border of 0 width.  It is not told to do so because
tables in braille do not have borders.

   Now let's look at the file which is included at the beginning of the
‘html.sem’ file.  This is ‘nemeth.sem’.  As with ‘html.sem’, a copy is
included in the appendix (*note Example files::), but it is not
necessarily the one that liblouisutdml is currently using.  It
illustrates several more things about how liblouisutdml uses
semantic-action files.

   The first thing you will notice is that for quite a few lines the
first and second columns are identical.  This is because the MathML
element and attribute names are part of a standard, and it was simplest
to use the element names for the semantic actions as well.  Most of
these actions do not do anything and could be replaced with the
‘generic’ semantic action.  They are retained for backward
compatibility.

   The first line of real interest is:

     math math

   Every mathematical expression begins with the element ‘’.  This is
therefore the root element of a mathematical expression.  However,
mathematical expressions are usually part of a document, so it is not
given the semantic action document.  The math semantic action causes
liblouisutdml to carry out special interpretation actions.  These will
become clearer as we continue to look at the ‘nemeth.sem’ file.  You
will note that this line has three columns.  The meaning of the third
column is discussed below.

   After another uninteresting line we come to two that illustrate
several more facts about semantic-action files:

     mfrac mfrac ^?,/,^#
     mfrac mfrac,linethickness,0 ^(,^;%,^)

   Like the math entry above, the first line has three columns.  While
the first two columns must always be present, the third column is
optional.  Here, it is also divided into subcolumns by commas.  The
element ‘<mfrac>’ indicates a fraction.  A fraction has two parts, a
numerator and a denominator.  In xml, we call these parts children of
‘<mfrac>’.  They may be represented in various ways, which need not
concern us here.  What is of real importance is that the third column
tells liblouisutdml to put the characters ‘~?’ before the numerator, ‘/’
between the numerator and denominator, and ‘~#’ after the denominator.
Later on, liblouis will translate these characters into the proper
representation of a fraction in the Nemeth Code of Braille Mathematics.
(For other mathematical codes, *note Implementing Braille Mathematics
Codes::).

   The second line is of even greater interest.  The first column is
again ‘mfrac’, but this line is for binomial coefficient.  The second
column contains three subcolumns, an element name, an attribute name and
an attribute value.  The attribute linethickness specifies the thickness
of the line separating the numerator and denominator.  Here it is 0, so
there is no line.  This is how the binomial coefficient is represented
in print.  The third column tells how to represent it in braille.
liblouisutdml will supply ‘~(’, upper number, ‘~%’, lower number, ‘~)’
to liblouis, which will then produce the proper braille representation
for the binomial coefficient.

   Returning to the line for the math element, we see that the third
column begins with a backslash followed by an asterisk.  The backslash
is an escape character which gives a special meaning to the character
which follows it.  Here the asterisk means that what follows is to be
placed at the very end of the mathematical expression, no matter how
complex it is.

   For further discussion of how the third column is used *note
Implementing Braille Mathematics Codes::.  The third column is not
limited to mathematics.  It can be used to add characters to anything
enclosed by an xml tag.

4.2 Semantic Actions in detail
==============================

Here is a complete list of the semantic actions which liblouisutdml
recognizes.  Some of them are also the names of styles.  These are
listed in the first table.  For a discussion of these, *note
Customization Configuring liblouisutdml::.

   Generally the format of a semantic action is:

     semanticAction elementSpecifier optionalArguments

   ‘elementSpecifier’ is the second-column value, which may be an
element name, an element-attribute pair or an element-attribute-value
triplet, separated by commas.  This specifies where a semantic action is
to be applied.  If it is solely an element then the action is applied if
this element is encountered.  If it is an element-attribute pair then
the action is applied if the given element also has the specified
attribute.  In the last case with an element-attribute-value triplet the
action is only applied if the element has the specified attribute and
the value of this attribute is equal to the specified value.

‘contents1 elementSpecifier’

     Note that the ‘contents1’, etc.  semantic actions are never
     assigned an actual ‘elementSpecifier’.  There used internally by
     the table of contents generator.  They should be assigned style
     settings, however.

‘contents2 elementSpecifier’

‘contents3 elementSpecifier’

‘contents4 elementSpecifier’

‘contentsheader elementSpecifier’

     This semantic action must be assigned an element specifier if used.
     See the discussion of it in *note style::.

‘document elementSpecifier’

‘heading1 elementSpecifier’

‘heading2 elementSpecifier’

‘heading3 elementSpecifier’

‘heading4 elementSpecifier’

‘para elementSpecifier’

   The following table explains each of the non-style semantic actions.
In general, each one performs a particular function.  If a third column
is given, the subcolumns will be inserted in order before each branch of
any subtree starting from ‘elementSpecifier’.

‘blankline elementSpecifier’

     This semantic action causes a blank line to appear in the output
     wherever it may occur.  It is useful for fine formatting
     independent of styles.  ‘elementSpecifier’ should be an empty
     element, that is, of the form ‘<elementSpecifier/>’.  If it is not,
     any content which it may contain will be ignored.

‘boldx elementSpecifier’

     Enclose the text which follows in braille bold indicators.  The ‘x’
     at the end of the semantic action name is there to prevent
     conflicts with names elsewhere in the software.  Just where the
     bold indicators will be placed is controlled by the liblouis
     translation table in use.

‘chemistry elementSpecifier’

     When a module to handle chemical notation is ready, this semantic
     action will invoke it.  The processing will be like that produced
     by the semantic action ‘math’.

‘changetable elementSpecifier’

     This semantic action is used to change the active translation
     table.  It can switch to a table for another language or to a table
     for computer braille in a mathematical expression, etc.
     ‘elementSpecifier’ is in the form ‘element,attribute’.  The
     document contains something like:

          <span lang="en-us-g1.ctb">
          This is uncontracted.
          </span>

     The specified table remains in effect from ‘<element
     attribute="tablename">’ until ‘</element>’, no matter what is
     between the two.  The previous table is then restored.

‘compbrl elementSpecifier’

     The material between ‘elementSpecifier’ and ‘/elementSpecifier’ is
     translated as computer braille, if the liblouis table in use
     provides for it.  Beginning and ending computer braille indicators
     are inserted if they are in the table.

‘configfile elementSpecifier filename’

     The ‘configfile’, ‘configstring’ and ‘configtweak’ semantic actions
     enable the configuration of liblouisutdml to be changed according
     to the contents of the document being transcribed.  ‘configfile’
     and ‘configstring’ take effect during the document analysis phase
     performed by ‘examine_document.c’.  ‘configtweak’ is effective
     during the transcription phase, performed by
     ‘transcribe_document.c’ and the functions called in this module.

     ‘elementSpecifier’ is the usual second-column value, which may be
     an element name, an element-attribute pair or an
     element-attribute-value triplet, separated by commas.  ‘filename’
     must be on one of the paths set in the ‘paths.c’ module.  The file
     may contain any configuration settings except those in the xml
     section.  These would be ineffective, since the document has
     already been parsed.

‘configstring elementSpecifier setting1=value1;setting2=value2;...’

     Note that the ‘setting=value’ pairs are separated by semicolons.
     Because the string may be longer than a screen line, you can use a
     backslash ‘\’ followed immediately by a line ending ‘\n’, to
     continue to another line.  The string must not contain any blanks.
     Any setting which can be specified in a file read with configfile
     can be specified in ‘configstring’.

‘configtweak elementSpecifier settings’

     ‘configtweak’ is identical to ‘configstring’ except that it is
     called in the transcription phase.  It can be used for things like
     changing translation tables.  For example:

          configtweak elementSpecifier literaryTextTable=fooTable;\
          mathExprTable=barTable

     ‘configtweak’ is not a generalization of ‘changetable’.  The latter
     changes the active table and applies to a subtree.  ‘configtweak’
     remains in effect until changed by another ‘configtweak’.

‘contracted elementSpecifier’

‘footer elementSpecifier’

     This semantic action is used to specify a footer which will be
     placed at the bottom of each page.

          <elementSpecifier>This is a footer</elementSpecifier>

‘generic elementSpecifier’

     This is a general-purpose semantic action.  If the third column is
     blank it does absolutely nothing.  If the third column contains a
     string or subcolumns its contents are placed in the output
     according to the usual rules.  That is, the first subcolumn is
     placed before the first branch of the subtree rooted at this node,
     the second is placed before the second branch, etc.  If the last
     (or only) subcolumn begins with ‘\*’ it is placed after the last
     branch, no matter how many branches there may be.

‘graphic elementSpecifier’

     When a module which can handle SVG graphics is ready this semantic
     action will invoke it.

‘htmllink elementSpecifier’

     This semantic action is used when the configuration file specifies
     ‘formatFor browser’.  It sets up a link which the browser can
     follow.

‘htmltarget elementSpecifier’

     This semantic action establishes a target for a link in the same
     file when ‘formatFor browser’ is specified in the configuration
     file.

‘italicx elementSpecifier’

     Enclose the text which follows in braille italic indicators.  The
     ‘x’ at the end of the semantic action name is there to prevent
     conflicts with names elsewhere in the software.  Just where the
     italic indicators will be placed is controlled by the liblouis
     translation table in use.

‘linespacing elementSpecifier digit’

     This semantic action specifies the number of blank lines to be left
     between adjacent lines in the output.  For example if the third
     column is ‘1’, lines will be double-spaced.  ‘0’ specifies normal
     spacing.  The number cannot be greater than ‘3’.  ‘linespacing’
     remains in effect until another ‘linespacing’ is encountered.  It
     should be assigned to an empty element.

‘maction elementSpecifier’

     In the early stages of development I thought that a separate piece
     of code might be needed for each of the MathML element tags.  It
     turned out, as noted elsewhere, that most of them could have been
     handled with the ‘generic’ semantic action.  They are retained for
     backward compatibility.  Therefore, unless this is not the case or
     additional information is needed, they are simlly listed.

‘maligngroup elementSpecifier’

‘malignmark elementSpecifier’

‘math elementSpecifier’

     Every mathematical expression begins with the element
     ‘<elementSpecifier>’ ‘math’ (which may have attributes and values),
     and ends with ‘</elementSpecifier>’ (‘/math’).  This is therefore
     the root element of a mathematical expression.  However,
     mathematical expressions are usually part of a document, so it is
     not given the semantic action document.  liblouisutdml will,
     however, handle files and strings which consist of nothing but a
     mathematical expression properly.  The ‘math’ semantic action
     causes liblouisutdml to carry out special interpretation actions.

‘menclose elementSpecifier’

‘merror elementSpecifier’

‘mfenced elementSpecifier’

‘mfrac elementSpecifier’

‘mglyph elementSpecifier’

‘mi elementSpecifier’

‘mlabeledtr elementSpecifier’

‘mmultiscripts elementSpecifier’

‘mn elementSpecifier’

‘mo elementSpecifier’

‘mover elementSpecifier’

‘mpadded elementSpecifier’

‘mphantom elementSpecifier’

‘mprescripts elementSpecifier’

‘mroot elementSpecifier’

     The MathML element ‘mroot’ is actually given the semantic action
     ‘reverse’.

‘mrow elementSpecifier’

     This can be important in implementing Math codes because it is
     often used to create visual groups, which may be significant for
     braille.

‘ms elementSpecifier’

‘mspace elementSpecifier’

     This element and its attributes can be helpful for determining
     spacing.

‘msqrt elementSpecifier’

‘mstyle elementSpecifier’

     This MathML element should usually have the semantic action ‘skip’.

‘msub elementSpecifier’

‘msubsup elementSpecifier’

‘msup elementSpecifier’

‘mtable elementSpecifier’

     The file ‘liblouisutdml.ini’ defines the style ‘matrix’.  The
     semantic-action files for math codes declare ‘mtable’ to be
     ‘matrix’.  Depending on the attributes of this element, it can be
     set to other styles, such as long division.  The ‘matrix’ style
     contains the setting ‘format alignColumnsLeft’.

‘mtd elementSpecifier’

     This element specifies a column in a mathematical table.  For the
     style ‘matrix’ the third column of the entry in a semantic-action
     file must contain ‘\*|ec’.  This indicates the end of the column.
     Other specifications using the liblouis ‘exactdots’ feature may
     also be necessary.

‘mtext elementSpecifier’

‘mtr elementSpecifier’

     This element specifies a row in a mathematical table.  The entry in
     a semantic-action file must contain ‘\*\er’ in the third column for
     the ‘matrix’ style, indicating the end of the row.  Other things
     may also need to be specified using the liblouis ‘exactdots’
     feature.  Note that rows are not declared as styles nested inside
     the ‘matrix’ style.  This is because the table must be considered
     as a whole.

‘munder elementSpecifier’

‘munderover elementSpecifier’

‘music elementSpecifier’

     When a module which can interpret MusicML and produce braille music
     notation is ready this semantic action will invoke it.

‘newpage elementSpecifier’

     This semantic action causes the rest of the current page to be left
     blank except for page numbers and footers.  A new page is then
     begun.  Like ‘blankline’, it is useful for fine formatting
     independent of styles.

‘no elementSpecifier’

     Originally, this semantic action was intended to be the default and
     to do nothing when an ‘elementSpecifier’ had no meaning for braille
     translation.  Later it was found that it should insert a blank
     space if parts of the text would run together, so this is now its
     action.

‘none elementSpecifier’

     This is a MathML element.

‘notranslate elementSpecifier’

     Output the text between the start and end tags exactly as written.
     It will, however, be formatted with appropriate line breaks, page
     numbers etc.  If you want to make sure that things appear on the
     same line separate them with an unbreakable space, ‘&#160;’ or
     ‘&#xa0;’.

‘pagenum elementSpecifier’

     The text between ‘<elementSpecifier>’ and ‘</elementSpecifier>’ is
     taken to be a print page number.  If it does not begin with a digit
     the string ‘\_’ is placed before it.  It is then passed to liblouis
     for translation according to the active table.  This table must
     contain an entry for translating ‘\_’ into a letter sign or
     whatever else is wanted.  This string is inserted so that roman
     page numbers will be handled properly.  Unnumbered page breaks are
     indicated with an empty pagenum tag:
     ‘<elementSpecifier></elementSpecifier>’.

‘reverse elementSpecifier’

     The branches of the subtree rooted at this node are reversed in
     order.  This is used in handling roots, where the arguments in the
     translation are in reverse order to those in MathML. the MathML
     element ‘mroot’ is declared with this semantic action

‘righthandpage elementSpecifier’

     If ‘interpoint yes’ has been specified in the configuration file,
     and the current page is a right-hand one, the rest of the page is
     skipped except for footer and page number.  the following left-hand
     page is similarly skipped.  Otherwise, the action is the same as
     ‘newpage’.

‘runninghead elementSpecifier’

     This semantic action is used to specify a running header, such as a
     book title, to be placed at the top of each page.  If the header is
     too long it will be truncated.

          <elementSpecifier>liblouisutdml Manual</elementSpecifier>

‘semantics elementSpecifier’

     This is a MathML action which seems to be irrelevant to braille
     translation.

‘skip elementSpecifier’

     Skip ahead until encountering the element ‘</elementSpecifier>’.
     Nothing in between will have any effect on the braille output.

‘softreturn elementSpecifier’
     Do a soft return, that is, start a new line without starting a new
     paragraph.  ‘elementSpecifier’ should be empty, for example,
     ‘
’.

‘uncontracted elementSpecifier’

     This semantic action seems superfluous and may be eliminated in the
     future.

‘underlinex elementSpecifier’

     Enclose the text which follows in braille underline indicators.

4.3 Pseudo-actions
==================

These actions affect the processing of semantic-action files.  They are
not connected with any tag in the document.  They are executed when they
are encountered in the processing of semantic-action files.

4.3.1 include
-------------

     include filename

   filename must be the name of a semantic action file.  The file is
compiled as though it were part of the file containing the ‘include’
entry.  Included files may include other files.

4.3.2 newentries
----------------

     newentries no

   The second column in this entry must contain ‘no’.  Any new entries
found in the document will be ignored.  No ‘appended_’ file will be
produced.  This affects only documents processed with this
semantic-action file.  The configuration setting ‘newEntries’ affects
all documents.

4.3.3 namespaces
----------------

     namespaces dtb=http://www.daisy.org/z3986/2005/dtbook/

   This pseudo-action is used to declare namespaces used in XPath
expressions.  (*note Using XPath Expressions::).  The format is
‘namespaces prefix1=url1,prefix2=url2,...’.  The list of namespaces may
not contain blanks.

4.4 Using XPath Expressions
===========================

The second column of a semantic action may contain an XPath expression
for matching nodes.  When an XPath expression is to be used the second
column should be of the format: ‘&xpath(<expression>)’ where
‘<expression>’ is the XPath expression to match nodes.

   When constructing your XPath expressions you may wish to consider the
following facts:

   • The XPath expression may contain brackets but they must match

   • liblouisutdml performs XPath matching from the document root, so
     you most likely want all XPath expressions to begin with double
     slash (‘//’).

   • If the source document uses namespaces for the nodes you wish to
     match then you must define the namespace in the semantic action
     file (*note namespaces::) and then prefix the node with the
     namespace (e.g.  for a namespace with alias ‘xhtml’ and node with
     name ‘p’, this would be ‘xhtml:p’)

   • You should be careful not to create XPath expressions which give
     overlapping node set results.  When liblouisutdml finds a match for
     a node it assigns the semantic action to that node and this will
     not be changed subsequently.  Note that this is unlike XSLT, where
     for each matcher a priority is calculated from the XPath expression
     while in liblouisutdml it is unpredictable which rule will win.

   • XPath expressions take precedence over ordinary semantic-file
     entries.

   As with other types of semantic actions, you may define arguments in
the third column of a semantic action using XPath expressions.

     para &xpath(//h4)

   This example causes any element with the name ‘h4’ to be given the
semantic action ‘para’, no matter what other assignments may be made to
it.

4.5 Using Macros
================

A semantic-action file permits only one action or style to be mentioned
in the first column.  Macros get around this limitation.  They define a
style and a series of semantic actions.  A macro name can also be in the
first column.

   Macros somewhat resemble styles.  They are defined in a configuration
file and used in a semantic-action file.  In a configuration file the
definition is of the form

     macro macroName macroBody

   In a semantic-action file they are invoked as follows:

     macroName element[,attribute[,value]] [parameters]

   Here is an example of a macro definition.

     macro useSpanish para,configtweak(literaryTextTable=es-Es-g2.ctb)

   In a semantic-action file it might be used as follows.

     useSpanish p,lang,ES

   The meanings of the various parts of a macro are as follows:

‘macroName’

     is a string of alphanumeric characters, of which the first must be
     a letter.

‘macroBody’

     is a series of items separated by commas.  It may not contain
     whitespace.  If it is too long to fit on one line it may be
     continued by using a backslash (‘\’) followed by enter.  It should
     not be more than 500 characters in length.  Each item is one of the
     following:

     A style name

          Only one style can be specified in a macro.  This is due to
          the way in which styles are handled.

     A semantic action, optionally with parameters

          The parameters are enclosed in parentheses.  They consist of
          whatever is legal in the third column for the particular
          semantic action.  If the parentheses are empty, that is,
          simply ‘()’ the contents of the third column of the macro
          invocation itself are used as the parameters.

     ‘pause’

          This is used after a style name so that text belonging to that
          style can be processed.  Semantic actions can be specified
          between the style name and the word ‘pause’.

     ‘endstyle’

          This causes the style to be terminated and the processing of
          any text which may have been entered into it to be completed.
          Semantic actions may be specified after the word ‘endstyle’.

     If a style has been specified and neither ‘pause’ nor ‘endstyle’
     has been used the style is terminated when the end of the macro has
     been reached, and the processing of text is completed.  (When the
     end_macro function is called by the program.)

5 Special Features
******************

5.1 Table of contents
=====================

A table of contents is produced for an xml file if the file contains a
tag which has been defined with the ‘contentsheader’ semantic action
(*note contentsheader: contentsheader semantic.) and also tags for the
‘heading1’, ‘heading2’, ‘heading3’ or ‘heading4’ semantic actions (*note
heading1: heading1 semantic.).  The table of contents will contain print
and braille page numbers if these features have been enabled.  A
sequence of fill characters will be inserted before the page numbers, so
that the latter are at the right margin.  The fill character can be
specified in a configuration file with the ‘lineFill’ setting (*note
lineFill: lineFill setting.).  The default fill character is an
apostrophe (dot 3).

   Five new styles have been defined for the table of contents.  The
first is the ‘contentsheader’ style (*note contentsheader style::),
which is used to specify where the table of contents should be placed
and the title that should be given to it.  In the latter respect it is
much like a heading style.  The others correspond to the four heading
levels and are ‘contents1’, ‘contents2’, ‘contents3’ and ‘contents4’.
These styles are chosen as appropriate while the table of contents is
being made.  Do not declare them in a semantic-action file.  See the
‘liblouisutdml.ini’ file for the current default definitions of all
these styles.

   The table of contents will be placed where the xml tag is that you
declared in the ‘contentsheader’ semantic action (*note contentsheader:
contentsheader semantic.).  Its title will be whatever is inside that
tag, formatted according to the definition of the ‘contentsheader’
style.  It begins on a new page.  After it is completed the braille page
number is reset to ‘beginningBraillePageNumber’ and another new page is
started.  This means that the xml tag with the ‘contentsheader’ semantic
action should occur at the end of the information which you want to be
at the head of the output, such as a title page, dedication, etc.

   It is not necessary that an xml file contain a tag with the
‘contentsheader’ semantic action.  If the file contains headers you can
obtain a table of contents by specifying ‘contents yes’ in a
configuration file or ‘-Ccontents=yes’ on the command line of
‘file2brl’.  In this case, the table of contents will appear at the
beginning of the output.  Pages will be numbered beginning with 1.  When
the table of contents is complete, the material in the file will start
on a new page and the page number will be the value given in
‘beginningBraillePageNumber’.

   The ‘contents1’, etc.  styles all have the ‘format contents’ setting.
This is a variant of the ‘leftJustified’ format.  It has been necessary
to change the way ‘firstLineIndent’ is handled to accommodate multilevel
lists.  Up till now, if ‘firstLineIndent’ was negative, the first line
would start at the real left margin, regardless of the value of
‘leftMargin’.  Now the value of ‘firstLineIndent’ is simply added to
‘leftMargin’.  This means that if it is negative it is really
subtracted.  For example, if ‘leftMargin’ is 4 and ‘firstLineIndent’ is
-2 the first line will start in cell 2.  If the result of adding these
two values is negative it is set to 0.

5.2 Back-translation
====================

     file2brl -b infile outfile

   infile must be a braille file.  It can have either upper-case or
lower-case letters, etc.  outfile will contain the back-translation
according to the configuration specifications.  It can be in two formats
according to the value of ‘backFormat’.  ‘ascii’ produces plain text
output.  The lines will generally correspond to the lines in the
original braille file.  ‘html’ produces a file in xhtml format.  This is
recommended, since it preserves print page numbers, if present and some
of the formatting of the original.  It can also be loaded into a browser
or word processor, which will format it for good readability.  Note that
for html format to work your liblouis table must contain the following
line:

     space \x001b 1b escape character

   To perform the back-translation operation, ‘file2brl’ uses the
liblouisutdml function ‘lbu_backTranslateFile’.

5.3 Reformatting
================

     file2brl -r infile outfile

   As in the previous section, infile must be a braille file.  It is
back-translated and then forward-translated to produce a braille file in
outfile which conforms to configuration specifications.  It is useful
for changing the line length and page length of a braille file.  New
braille page numbers will be generated if ‘braillePages yes’ is
specified.  If ‘backFormat html’ has been specified, print page numbers
will be reproduced in the appropriate places.  Some formatting may be
lost.

5.4 Interlining
===============

Interlining means printing the original text between the lines of
translated braille.  It requires special embossers or special methods.
The present way in which liblouisutdml produces interlining relies on
back-translation.  However, it is inadequate for mathematics and depends
too much on the quality of the liblouis tables.  It is scheduled to be
replaced, so you should not use it.

5.5 Browser-Friendly Output
===========================

     file2brl infile outfile -CformatFor=browser

   infile can be any of the file types accepted by ‘file2brl’ (xml, html
or text).  If it contains html links or targets they will be formatted
so that a browser can use them.  This may be useful if a file contains
internal links to different sections, such as its own table of contents.
Text will be translated and formatted according to configuration
specifications.  If the file contains mathematics expressed as MathML it
will be translated according to the mathematics code specified by the
configuration.  outfile should have the extension ‘.html’.  It will
actually be xhtml.  The ‘-CformatFor=browser’ part of the above example
specifies a configuration setting, which, of course, can also be
specified in a configuration file.

5.6 ‘CDATA’ Sections
====================

A ‘cdata’ section may be given the semantic actions ‘skip’, ‘no’ or
‘code’.  In the first case, the data in the ‘cdata’ section is ignored.
In the second case, it is inserted into the output with no translation.
In the third case it is translated into computer braille and inserted
into the output.  Any other semantic action has the same effect as ‘no’.

5.7 End notes
=============

An endnote is defined as the link between a reference character in the
body of the text and a description at the end of the output document.

5.7.1 Use of Endnotes
---------------------

The position of the reference character in the body of the text is
defined by the ‘noteref’ semantic action (*note noteref: noteref
semantic.), which is then linked to a ‘note’ semantic action (*note
note: note semantic.) (which can appear anywhere within the input file)
with the same id.  The content of ‘note’ will appear at the end of the
output document, along with its corresponding reference character and
the page and line numbers of where the reference character appears in
the text.

   A heading for the first endnote page can be set using the
‘notesheader’ semantic action (*note notesheader: notesheader
semantic.), and a small note can also be placed after this heading, but
before the endnotes, by using the ‘notesdescription’ semantic action
(*note notesdescription: notesdescription semantic.).

   The endnote page created will follow any formatting (page numbers,
headers, footers) from the last page in the document.

5.7.2 Output
------------

Let's look at an example.  The following text in an input file

     some text <mynoteref id="1">1</mynoteref> some text
     ...
     <mynote id="1">Endnote Description</mynote>

   will produce a reference to the end note in the output as follows
(with usual representation of numbers):

     some text 99#a some text

   The ‘99’ in ascii is used as the indicator for an endnote reference.
And it will also produce an entry on the end notes page as follows:

     #a p#g#b Endnote Description

   with the usual representation of numbers and, in this example, the
reference to the note, i.e.  the reference character appearing on the
2nd line of the 7th page.

5.7.3 Configuration
-------------------

‘endnotes yes’

     Choose whether to use endnotes or not.  Choosing ‘no’ will ignore
     anything enclosed by all the semantic actions *note Semantic
     Actions::.

5.7.4 Styles
------------

The semantic actions ‘note’, ‘notesdescription’, and ‘notesheader’ have
corresponding styles.

‘style note’

     Each endnote on the endnote page will use this style

‘style notesheader’

     The style used by the title on the endnote page

‘style notesdescription’

     The style used by the note just after the title on the endnote page

   The ‘noteref’ semantic action (*note noteref: noteref semantic.) will
inherit its style.

5.7.5 Semantic Actions
----------------------

‘note elementSpecifier id’

     Defines the endnote displayed at the bottom of the file.  The id
     attribute has to be unique, and be identical to the id attribute in
     a ‘noteref’ in the file in order to be displayed, but the ‘note’
     action can appear before the corresponding ‘noteref’ action if
     needed.

     Given the following definition in the semantic action file

          note    mynote,idref

     we could define an endnote in the input file as follows:

          <mynote idref="1">This is an endnote</mynote>

‘noteref elementSpecifier id’

     Defines the position where the endnote reference character should
     be placed, as well as the endnote reference character in the
     endnote at the bottom of the file.  The order that these appear in
     the input file determines the order that they appear in the endnote
     section.

     Given the following definition in the semantic action file

          noteref    mynoteref,idref

     we could place a reference to an endnote in the input file as
     follows:

          <mynoteref idref="1">*</mynoteref>

‘notesheader elementSpecifier’

     The text enclosed defines the header to be placed at the top of the
     first endnote page.  For multiple of these defined in the input,
     the last one is used.

     Given the following definition in the semantic action file

          notesheader    mynotesheader

     we could define the page header of the first endnotes page in the
     input file as follows:

          <mynotesheader>Endnote Page Header</mynotesheader>

‘notesdescription elementSpecifier’

     Defines some text to be placed after the ‘notesheader’ semantic
     action (*note notesheader: notesheader semantic.), but before the
     rest of the endnotes.  Again, for multiple definitions in the input
     file, the last one will be used.

     Given the following definition in the semantic action file

          notesdescription    mynotesdescription

     we could define some text to appear on the first endnotes page in
     the input file as follows:

          <mynotesdescription>Endnote Page Text</mynotesdescription>

5.7.6 Example
-------------

So, to define end notes we need an input file (*note endnotes.xml::)
containing end notes and references to them , end notes have to be
enabled in the ini file or via command line options (*note
endnotes.ini::) and finally we have to specify which element in the
input file constitutes an endnote and a reference to it by defining this
in a semantic action file (*note endnotes.sem::).  Optionally we can
also define styles for the notes, the header of the notes page and the
descriptive text (*note endnote styles::).

   The following example shows the relevant excerpts in the input, sem
and configuration files together with the resulting output (*note
endnote output::).

5.7.6.1 input.xml
.................

     <?xml version=""1.0" encoding="UTF-8"?>
     <doc>
         <notesheader>not seen header</notesheader>
         <notesdescription>not seen description</notesdescription>

         <note id = "2">Endnote Description 2</note>

         <p>Foo<noteref id = "1">1</noteref>Bar.</p>
         <p>Foo<noteref id = "2">ref2</noteref>Bar.</p>

         <notesheader>Endnotes</notesheader>
         <notesdescription>Some descriptive text</notesdescription>

         <note id = "1">Endnote Description 1</note>
     </doc>

5.7.6.2 liblouisutdml.ini
.........................

     endnotes yes

5.7.6.3 endnotes.sem
....................

     note                note,id
     noteref             noteref,id
     notesheader         notesheader
     notesdescription    notesdescription

5.7.6.4 styles.cfg
..................

     style note
         leftMargin 2
         firstLineIndent 2

     style notesheader
         format centered

     style notesdescription
         format leftJustified

5.7.6.5 output.txt
..................

     Foo 99#a Bar.
     Foo 99ref#b Bar.






     -page-
          Endnotes Header

     Some descriptive text

     #a p#a#a Endnote
       Description #a
     ref#b p#a#b Endnote
       Description #b
     -page-

6 Special Formats
*****************

6.1 Tables
==========

Various methods of handling tables can be devised.  One that is in
current use requires the following lines in a semantic-action file:

     list tr \*;
     generic td \*;\s

   The ‘list’ style specifies that the first line should begin at the
left margin and subsequent lines should be indented two spaces.  The
third column specifies that a semicolon should be placed at the very end
of the row.  The ‘generic’ semantic action causes each column in the
table to be followed by a semicolon and a space, as specified in the
third column.  your liblouis table must also contain the following line:

     noback always ;\s; 0

6.2 Reserving Space for Graphics
================================

Your configuration files should contain lines like these:

     style graphspace
     rightHandPage yes

   In your semantic-action file you must assign a tag to this style.
Note that the semantic action ‘graphic’ will invoke code to translate
SVG graphics when this feature is developed.  You can nest various
styles within the ‘graphspace’ style, such as a caption at the
beginning.  In particular, you should have another invocation of
‘graphspace’ at the end to skip to a new page, or the next right-hand
page if you are using interpoint.

6.3 Displayed Text
==================

Conventions for setting off a block of text from the rest vary.  you may
wish to use the ‘quotation’ style or devise a style of your own.

6.4 Displayed Mathematics
=========================

Again, conventions vary.  you can define your own style for this purpose
and invoke it according to the attributes of the ‘math’ tag.

6.5 Spatial Layouts in Mathematics
==================================

This is also known as 2d mathematics.  It spreads out complex fractions
and other materials for easier viewing.  It is being developed based on
the specifications of MathML 3.

6.6 Arithmetic Examples
=======================

This is another format that is being developed using MathML 3.  It is
difficult in earlier versions.

6.7 Poetry
==========

‘liblouisutdml.ini’ defines two styles which can be used to format
poetry, as follows:

     style stanza
     linesBefore 1
     linesAfter 1
     style line
     leftMargin 2
     firstLineIndent -2

   Your document might then contain the following from Samuel Taylor
Coleridge's "Rime of the Ancient Mariner":

     <stanza>
     <line>He holds him with his glittering eye</line>
     <line>The wedding guest stands still</line>
     <line>And listens like a three-years' child.</line>
     <line>He has no force nor will.</line>
     </stanza>

   Note that when stanzas follow each other liblouisutdml will produce
only one blank line between them, not two.

6.8 Dividing a Book Into Volumes
================================

Details are still under development.  However, this much can be said.
First, obtain a table of contents for the whole book.  This requires
that your configuration files have the following settings:

     contents yes
     braillePages yes

   This will tell you the approximate braille pages on which things will
be placed in the finished product.  You can then calculate the number of
pages required for each chapter and how many chapters will fit in a
volume of your preferred size.  From the point of view of the braille
reader, it is desirable to avoid splitting chapters between volumes.

   At this point you will probably have to edit the source xml file to
indicate the beginning and end of volumes.  You can define a
liblouisutdml style called ‘volume’ and assign appropriate xml tags to
it in a semantic-action file.  Within the volume style you can nest a
title page, chapters, etc.  A volume table of contents is still under
development.

7 Implementing Braille Mathematics Codes
****************************************

Much information useful in implementing braille mathematical codes is
given in the sections on styles and on semantic actions, especially in
the discussion of MathML semantic actions.  The chapter on Special
Formats also contains much useful information.

   The Nemeth Code of Braille Mathematical and Science Notation, BAUK
maths and Marburg Maths have been implemented.  the Nemeth code was the
first and uses an implementation which is now obsolete.  The discussion
below will concentrate on the implementation of BAUK Maths.

   Four tables are used to translate xml documents containing a mixture
of text and mathematics.  They can be found in the subdirectory
‘lbu_files’ of the liblouisutdml directory and in the ‘tables’
subdirectory of the liblouis distribution.  First, the semantic-action
file ‘ukmaths.sem’ is used to interpret the mathematical portions of the
xml document (The text portions are interpreted by another
semantic-action file which will not be discussed here).  After the math
and text have been interpreted, two liblouis tables, ‘ukmaths.ctb’ and
‘en-us-g2.ctb’ are used to translate them.  The latter table may be
replaced by another table at the user's discretion.  Each piece of
mathematics or text is translated separately and the pieces are strung
together with blanks between them.  This results in inaccuracies where
mathematics meets text.  The fourth table, also a liblouis table, is
used to remove these inaccuracies.  It is called ‘ukmaths_edit.ctb’, and
it does things like removing the multi-purpose indicator before a blank,
inserting the punctuation indicator before a punctuation mark following
a math expression, and removing extra spaces.  This table may need
editing if a different text translation table is used.

   The general format and use of semantic-action files were discussed in
the section *note Connecting with the xml Document - Semantic-Action
Files: Connecting with the xml Document.  In this section we shall
concentrate on the optional third column, which is used a lot in
‘ukmaths.sem’.  While the first two columns can be generated by
liblouisutdml but must be edited by a person, the third column must
always be provided by a human.

   As previously stated, the third column tells liblouisutdml what
characters to insert to inform liblouis how to translate the math
expression.  In fact, you can tell liblouis exactly what dots to insert.
This relies on the liblouis opcode ‘exactdots’.  If you look at the file
‘example_ukmaths.ctb’ you will see lines like the following:

     exactdots @126
     exactdots @345
     exactdots @123456

   This opcode has only a string operand.  liblouis assumes that the
characters following the at sign are its dot pattern.

   In your semantic-action file you might have lines like:

     mfenced mfenced @126,@345
     mfenced mfenced,open,{ @246,@135
     mover mover ,@4-346,@12456

   By using this approach you do not have to remember which characters
will produce the desired dots in a particular liblouis table or on a
particular output device.

   Sometimes an element or tag can have an indeterminate number of
children.  This is true of ‘’ itself.  Yet, it may be necessary to
place some characters after the very last element.  Let us look at the
‘’ entry.

     math math \eb,\*\ee

   First let us discuss escape sequences starting with a backslash.
These are basically the same as in liblouis.  The sequence ‘\e’ is
shorthand for the escape character, which would otherwise be represented
by ‘\x001b’.  The beginning of a math expression is denoted by an escape
character followed by the letter b and the end by an escape character
followed by the letter ‘e’.  This enables the editing table to do such
things as drop the baseline indicator at the end of a math expression
and insert a number sign at the beginning, if needed.

   Not found in liblouis is the sequence ‘\*’.  This means to put what
follows after the very last child of the math element, no matter how
many there are.

   As another example consider:

     mtd mtd \*\ec

   ‘mtd’ is the MathML tag for a table column.  There may be many
children of this tag.  The entry says to put an escape character (hex
1b), plus the letter ‘c’, after the very last of them.

   As a final example consider:

     mtr mtr ^.^\,^(,\*^.^\,^)\er

   ‘mtr’ is the MathML tag for a row in a table, in this case a matrix.
Each row in a matrix must begin with the dot pattern ‘46-6-12356’ and
end with the dot pattern ‘46-6-12456’.  As usual a caret is placed
before the corresponding characters.  Since dot 6 is a comma, it must be
escaped.  This is done by placing a backslash before the comma.  There
are two subcolumns.  the first contains the characters to be placed at
the beginning of each row.  The second starts with ‘\*’, signifying that
the characters following it are to be placed at the end of everything in
this row.  A subcolumn starting with ‘\*’ must be the last (or only)
subcolumn.

   Here this last subcolumn ends with an escape character and the letter
<r>, signifying the end of a row.

   So much for the semantic action file.  Even though the characters in
the third column were chosen to correspond with nemeth characters, they
may not have to be changed for other math codes.  liblouis can replace
them with anything needed.

   This brings us to a consideration of the two tables used by liblouis
to translate mathematics texts.  The first, ‘en-mathtext.ctb’ is used to
translate text appearing outside math expressions.  It is necessary
because the Nemeth code requires modifications of Grade 2 braille.
Other math codes may not have this requirement.

   The table actually used to translate mathematics is ‘nemeth.ctb’.  It
includes two other tables, ‘chardfs.cti’ and ‘nemethdefs.cti’.  The
first gives ordinary character definitions and is included by all the
other tables.  Note however, that the unbreakable space, ‘\x00a0’, is
translated by dot 9.  This is used before and after the equal sign and
other symbols in ‘nemeth.ctb’.  The second table contains character
definitions for special math symbols, most of which are Unicode
characters greater than ‘\x00ff’.  The Greek letters are here.  So are
symbols like the integral sign.

   Most of the entries in ‘nemeth.ctb’ should be familiar from other
tables.  The unfamiliar ones follow the comments ‘# Semantic pairs’ and
‘# pass2 corrections’.  The first simply replace characters preceded by
a caret with the character itself.  The second make adjustments in the
code generated directly from the ‘nemeth.sem’ file.  The pass2 opcode is
discussed in the liblouis documentation (*note Overview:
(liblouis)Top.).  Here are some comments on a few of the entries in
‘nemeth.ctb’.

     pass2 @1456-1456 @6-1456

   Replaces double start-fraction indicators with the start complex
fraction indicator.

     pass2 @3456-3456 @6-3456

   Replaces double end-fraction indicators with the end-complex-fraction
indicator.

     pass2 @56[$d1-5]@5 *

   Removes the subscript and baseline indicators from numeric
subscripts.

     pass2 @5-9 @9

   Removes the baseline or multipurpose indicator before an unbreakable
space generated by the translation of an equal sign, etc.

     pass2 @45-3-5 @3

   Replaces a superscript apostrophe with a simple prime symbol.

     pass2 @9[]$d @3456

   Puts a number sign before a digit preceded by a blank.

     pass2 @9-0 @9

   Removes a space following an unbreakable space.

   We now come to the fourth and last table used for math translation,
the editing table, ‘nemeth_edit.ctb’.  As explained at the beginning,
this table is used to remove inaccuracies where math translation butts
up against text translation.  For example, the Nemeth code puts numbers
in the lower part of the cell.  However, punctuation marks are also in
the lower part of the cell.  So Nemeth puts a punctuation indicator,
dots ‘456’, in front of any lower-cell punctuation that immediately
follows a mathematical expression.  If this occurs inside Mathml it is
handled by ‘nemeth.ctb’.  However, a MathML expression is often followed
by a punctuation mark which is the first part of text.  liblouisutdml
puts a blank between math and text, but this can result in a
mathematical expression followed by a blank and then, say, a period,
dots ‘256’.  ‘nemeth_edit.ctb’ replaces the blank with the punctuation
indicator.

   When you look at ‘nemeth_edit.ctb’ you will see that it begins with
an include of ‘chardefs.cti’.  Most of the entries are ordinary, but
some are interesting.  for example,

     always "\s 0

   replaces the baseline or multipurpose indicator followed by a space
with just a space.

8 Programming with liblouisutdml
********************************

8.1 License
===========

Liblouisutdml may contain code borrowed from the Linux screenreader
BRLTTY, Copyright © 1999-2009 by the BRLTTY Team.

Copyright © 2004-2009 ViewPlus Technologies, Inc.  <www.viewplus.com>.

Copyright © 2006,2009 Abilitiessoft, Inc.  <www.abilitiessoft.org>.

   Liblouisutdml is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

   Liblouisutdml is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
License along with Liblouisutdml.  If not, see
<http://www.gnu.org/licenses/>.

8.2 Overview
============

liblouisutdml is an "extensible renderer", designed to translate a wide
variety of xml and text documents into braille, but with a special
emphasis on technical material.  The overall operation of liblouisutdml
is controlled by a configuration file.  The way in which a particular
type of xml document is to be rendered is specified by a semantic-action
file for that document type.  Braille translation is done by the
liblouis braille translation and back-translation library (*note
Overview: (liblouis)Top.).  Its operation, in turn is controlled by
translation table files.  All these files are plain text and can be
created and edited in any text editor.  Configuration settings can also
be specified on the command line of the console-mode transcription
program ‘file2brl’.

   The general operation of liblouisutdml is as follows.  It uses the
libxml2 library to construct a parse tree of the xml document.  After
the parse tree is constructed, a function called ‘examine_document’
looks it over and determines whether math translation tables, etc.  are
needed.  ‘examine_document’ also constructs a prototype semantic-action
file, if one does not exist already.  It may also construct another file
containing entries not found in an existing file.  When it is finished,
another function, called ‘transcribe_document’, does the actual braille
transcription.  It calls ‘transcribe_math’ to handle MathML subtrees,
‘transcribe_chemistry’ for chemical formula subtrees,
‘transcribe_graphic’ for SVG graphics, etc.  Entities are translated to
Unicode, if they are not already.  Sequences of symbols indicate
superscripts, return to the baseline, subscripts, start and end of
fractions, etc.  The Braille translator and back-translator library
liblouis is used to do the braille translation.

   The ‘transcribe_math’ function works in conjunction with the latest
version of liblouis and a special math translation table to transcribe
most mathematical expressions into good braille mathematical Code.

   The functions which are not ready for use at the moment, such as
‘transcribe_chemistry’, are only skeletons.  However, I hope that
‘transcribe_graphics’ can be expanded in the near future to use the
graphics capability of the Tiger tactile graphics embossers.

   The latest versions of liblouisutdml and liblouis can be downloaded
from <www.liblouis.io>.  This site also contains links to a mailing list
and to project pages on github.com.  Note that liblouisutdml will only
work with the latest version of liblouis.

   liblouisutdml can be compiled to use either 16-bit or 32-bit Unicode
internally.  This is inherited from liblouis, so liblouis must be
compiled first and then liblouisutdml.  Wherever 16 bits are mentioned
in this document, read 32 if you have compiled the library for 32 bits.

8.3 Files and Paths
===================

liblouisutdml uses three kinds of files, configuration files,
semantic-action files, and liblouis translation tables.  The first two
are discussed elsewhere in this documentation.  liblouis translation
tables are discussed in the liblouis documentation (*note Overview:
(liblouis)Top.) which is distributed with liblouis.

   Note that liblouisutdml also generates some files, all of which are
placed in the current directory.  These files are new prototype
semantic-action files, additions to old semantic-action files, temporary
files, and log files.  The first two can be used to extend the
capability of liblouisutdml to process xml documents.  The latter two
are useful for debugging.

   liblouisutdml determines the paths on which it will search for files
at run time, as part of its initialization.  First, if the first file in
a configuration file list includes a path, liblouisutdml will search
first on this path.  The path may be either absolute or relative.  Only
the first filename in a configuration file list may have a path.  Next,
in Windows, liblouisutdml determines the path to itself.  this is the
second path on which it will look for files.  The liblouis ‘tables’
directory and the liblouisutdml ‘lbu_files’ directory are relative to
this path.  In Unix systems, including the Mac,, these directories are
absolute paths determined at compile time.  liblouisutdml searches first
the ‘tables’ directory and then the ‘lbu_files’ directory.  Finally, it
establishes the current directory as the final path to be searched.  If
you wish the current directory to be the first path searched, prefix the
first configuration file name with ‘./’ for Unix or ‘.\’ for Windows.

   Paths are handled in the ‘paths.c’ module.  This contains the
function ‘set_paths’, which is called from ‘readconfig.c’ and in turn
calls ‘addPath’ in the ‘paths.c’ module.

8.4 lbu_version
===============

     char *lbu_version (void)

   This function returns a pointer to a character string containing the
version of liblouisutdml.  Other information such as the release date
and perhaps notable changes may be added later.

8.5 lbu_initialize
==================

     void * lbu_initialize (
     const char *configFilelist,
     const char *logFileName,
     const char *settingsString)

   This function initializes the libxml2 library, processes
‘liblouisutdml.ini’ and configuration settings given in the
configuration files given in ‘configFilelist’.  This is a list of
configuration file names separated by commas.  If the first character is
a comma it is taken to be a string containing configuration settings and
is processed like the ‘settingsString’ string.  if the parameter
‘settingsString’ is not ‘NULL’ it is processed last.  Such a string must
conform to the format of a configuration file.  Newlines should be
represented with ASCII 10.  If ‘logfilename’ is not ‘null’, a log file
is produced on the current directory.  If it is ‘null’ any messages are
printed on stderr.  The function returns a pointer to the ‘UserData’
structure.  This pointer is ‘void’ and must be cast to ‘(UserData *)’ in
the calling program.  To access the information in this structure you
must include ‘louisutdml.h’.  This function is used by ‘file2brl’.

8.6 lbu_translateString
=======================

     int lbu_translateString (
     const char *configfilelist,
     char * inbuf,
     widechar *outbuf,
     int *outlen,
     unsigned int mode)

   This function takes a well-formed xml expression in ‘inbuf’ and
translates it into a string of 16-bit (or 32-bit if this has been
specified in liblouis) braille characters in ‘outbuf’.  The xml
expression must be immediately followed by a zero or null byte.  Leading
whitespace is ignored.  If it does not then begin with the characters
‘<?xml’ an xml header is added.  If it does not begin with ‘<’ it is
assumed to be a text string and is translated accordingly.  The header
is specified by the ‘xmlHeader’ line in the configuration file.  If no
such line is present, a default header specifying UTF-8 encoding is
used.  The ‘mode’ parameter specifies whether you want the library to be
initialized.  If it is 0 everything is reset, the ‘liblouisutdml.ini’
file is processed and the configuration file and/or string (see previous
section) are processed.  If ‘mode’ is 1 liblouisutdml simply prepares to
handle a new document.  For more on the ‘mode’ parameter see the next
section.

   Which 16-bit character in ‘outbuf’ represents which dot pattern is
indicated in the liblouis translation tables.  The ‘configfilelist’
parameter points to a configuration file or string.  Among other things,
this file specifies translation tables.  It is these tables which
control just how the translation is made, whether in Grade 2, Grade 1,
the Nemeth Code of Braille Mathematics or something else.

   Note that the ‘*outlen’ parameter is a pointer to an integer.  When
the function is called, this integer contains the maximum output length.
When it returns, it is set to the actual length used.  The function
returns 1 if no errors were encountered and a negative number if a
complete translation could not be done.

8.7 lbu_translateFile
=====================

     int lbu_translateFile (
     char *configfilelist,
     char *inputFileName,
     char *outputFileName,
     unsigned int mode)

   This function accepts a well-formed xml document in ‘inputFilename’
and produces a braille translation in ‘outputFilename’.  As for
‘lbu_translateString’, the ‘mode’ parameter specifies whether the
library is to be initialized with new configuration information or
simply prepared to handle a new document.  In addition, the ‘mode’
parameter can specify that a document is in html, not xhtml.
‘liblouisutdml.h’ contains an enumeration type with the values
‘dontInit’ and ‘htmlDoc’.  These can be combined with an or (‘|’)
operator.  The input file is assumed to be encoded in UTF-8, unless
otherwise specified in the xml header.  The encoding of the output file
may be UTF-8, UTF-16, UTF-32 or Ascii-8.  This is specified by the
‘outputEncoding’ line in the configuration file, ‘configfilelist’.  The
function returns 1 if the translation was successful.

8.8 lbu_translateTextFile
=========================

     int lbu_translateTextFile (
     char *configfilelist,
     char *inputFileName,
     char *outputFileName,
     unsigned int mode)

   This function accepts a text file in ‘inputFilename’ and produces a
braille translation in ‘outputFilename’.  The input file is assumed to
be encoded in Ascii8.  However, utf-8 can be specified with the
configuration setting ‘inputTextEncoding utf8’.  Blank lines indicate
the divisions between paragraphs.  Two blank lines cause a blank line
between paragraphs (or headers).  The output file may be in UTF-8,
UTF-16, or Ascii8, as specified by the ‘outputEncoding’ line in the
configuration file, ‘configfilelist’.  As for ‘lbu_translateString’, the
‘mode’ parameter specifies whether complete initialization is to be done
or simply initialization for a new document.

8.9 lbu_backTranslateFile
=========================

     int lbu_backTranslateFile (
     char *configfilelist,
     char *inputFileName,
     char *outputFileName,
     unsigned int mode)

   This function accepts a braille file in ‘inputFilename’ and produces
a back-translation in ‘outputFilename’.  The input file is assumed to be
encoded in Ascii8.  The output file is in either plain text or html,
according to the setting of ‘backFormat’ in the configuration file.
Html files are encoded in UTF8.  In plain-text, blank lines are inserted
between paragraphs.  The output file may be in UTF-8, UTF-16, or Ascii8,
as specified by the ‘outputEncoding’ line in the configuration file,
‘configfilelist’.  The mode parameter specifies whether or not the
library is to be initialized with new configuration information, as
described in the section on ‘lbu_translateString’ (*note
lbu_translateString::).

8.10 lbu_free
=============

     void lbu_free (void)

   This function should be called at the end of the application to free
all memory allocated by liblouisutdml and liblouis.  If you wish to
change configuration files during your application, use a ‘mode’
parameter of 0 on the function call using the new configuration
information.  This will call the ‘lbu_free’ function automatically.

Appendix A Example files
************************

This manual refers to files to files contained in liblouisutdml and
liblouis.  You might want to look up these files in the source
distribution (located under ‘lbu_files/’) or online in the source code
repository (https://github.com/liblouis/liblouisutdml) and use them as a
reference or to study how things are done.  In particular the following
files are mentioned:

‘liblouisutdml.ini’

     The main initialization file
     (https://github.com/liblouis/liblouisutdml/blob/master/lbu_files/liblouisutdml.ini)
     that contains the minimal settings for liblouisutdml operation.

‘preferences.cfg’

     The preferences.cfg
     (https://github.com/liblouis/liblouisutdml/blob/master/lbu_files/preferences.cfg)
     file contains all possible configuration settings, with sample
     values, where appropriate.  It is used by the ‘file2brl’
     command-line interface if no configuration file is given.

‘html.sem’

     An example of a semantic action file to handle html
     (https://github.com/liblouis/liblouisutdml/blob/master/lbu_files/html.sem).

‘nemeth.sem’

     An example of a semantic action file to handle math
     (https://github.com/liblouis/liblouisutdml/blob/master/lbu_files/nemeth.sem).

‘ukmaths.sem’

     An example of a semantic action file to handle math
     (https://github.com/liblouis/liblouisutdml/blob/master/lbu_files/ukmaths.sem).

‘ukmaths.ctb’

     The liblouis UK Maths table for mathematics
     (https://github.com/liblouis/liblouis/blob/master/tables/ukmaths.ctb).

‘ukmaths_edit.ctb’

     The liblouis table for post-translation editing of UK Maths
     (https://github.com/liblouis/liblouis/blob/master/tables/ukmaths_edit.ctb).

Configuration Settings Index
****************************

* Menu:

* backFormat:                            outputFormat.       (line  560)
* backLineLength:                        outputFormat.       (line  567)
* beginningPageNumber:                   outputFormat.       (line  458)
* bottomBoxline:                         style.              (line  907)
* braillePageNumberAt:                   outputFormat.       (line  470)
* braillePageNumberFormat:               style.              (line  780)
* braillePages:                          outputFormat.       (line  444)
* cellsPerLine:                          outputFormat.       (line  412)
* center:                                style.              (line  862)
* compbrailleTable:                      translation.        (line  592)
* continuePages:                         outputFormat.       (line  478)
* dontSplit:                             style.              (line  788)
* editTable:                             translation.        (line  607)
* endnotes:                              Configuration.      (line 1955)
* entity:                                xml.                (line  630)
* fileEnd:                               outputFormat.       (line  436)
* firstLineIndent:                       style.              (line  727)
* firstLineIndent <1>:                   style.              (line  831)
* firstLineIndent <2>:                   style.              (line  838)
* firstLineIndent <3>:                   style.              (line  845)
* firstLineIndent <4>:                   style.              (line  852)
* firstLineIndent <5>:                   style.              (line  871)
* firstLineIndent <6>:                   style.              (line  878)
* firstLineIndent <7>:                   style.              (line  886)
* firstLineIndent <8>:                   style.              (line  893)
* format:                                style.              (line  747)
* format <1>:                            style.              (line  821)
* format <2>:                            style.              (line  833)
* format <3>:                            style.              (line  840)
* format <4>:                            style.              (line  847)
* format <5>:                            style.              (line  854)
* formatFor:                             outputFormat.       (line  549)
* hyphenate:                             outputFormat.       (line  529)
* ignoreEmptyPages:                      outputFormat.       (line  494)
* inputTextEncoding:                     outputFormat.       (line  545)
* internetAccess:                        xml.                (line  639)
* interpoint:                            outputFormat.       (line  418)
* keepWithNext:                          style.              (line  797)
* leftMargin:                            style.              (line  715)
* leftMargin <1>:                        style.              (line  832)
* leftMargin <2>:                        style.              (line  839)
* leftMargin <3>:                        style.              (line  846)
* leftMargin <4>:                        style.              (line  853)
* lineEnd:                               outputFormat.       (line  424)
* lineFill:                              outputFormat.       (line  572)
* linesAfter:                            style.              (line  710)
* linesAfter <1>:                        style.              (line  820)
* linesAfter <2>:                        style.              (line  863)
* linesBefore:                           style.              (line  704)
* linesBefore <1>:                       style.              (line  819)
* linesBefore <2>:                       style.              (line  861)
* linesBefore <3>:                       style.              (line  870)
* linesPerPage:                          outputFormat.       (line  415)
* literaryTextTable:                     translation.        (line  583)
* MathexpTable:                          translation.        (line  604)
* mathtextTable:                         translation.        (line  597)
* mergeUnnumberedPages:                  outputFormat.       (line  512)
* newEntries:                            xml.                (line  646)
* newPageAfter:                          style.              (line  767)
* newPageBefore:                         style.              (line  761)
* orphanControl:                         style.              (line  803)
* outputEncoding:                        outputFormat.       (line  537)
* pageEnd:                               outputFormat.       (line  432)
* pageNumberBottomSeparateLine:          outputFormat.       (line  525)
* pageNumberTopSeparateLine:             outputFormat.       (line  518)
* pageSeparator:                         outputFormat.       (line  482)
* pageSeparatorNumber:                   outputFormat.       (line  489)
* paragraphs:                            outputFormat.       (line  452)
* printPageNumberAt:                     outputFormat.       (line  463)
* printPageNumberRange:                  outputFormat.       (line  504)
* printPages:                            outputFormat.       (line  440)
* rightHandPage:                         style.              (line  773)
* rightMargin:                           style.              (line  722)
* semanticFiles:                         xml.                (line  618)
* skipNumberLines:                       style.              (line  741)
* topBoxline:                            style.              (line  902)
* translate:                             style.              (line  734)
* uncontractedTable:                     translation.        (line  587)
* xmlheader:                             xml.                (line  626)

Semantic Action Index
*********************

* Menu:

* blankline:                             Semantic Actions in detail.
                                                             (line 1275)
* boldx:                                 Semantic Actions in detail.
                                                             (line 1283)
* changetable:                           Semantic Actions in detail.
                                                             (line 1297)
* chemistry:                             Semantic Actions in detail.
                                                             (line 1291)
* compbrl:                               Semantic Actions in detail.
                                                             (line 1313)
* configfile:                            Semantic Actions in detail.
                                                             (line 1320)
* configstring:                          Semantic Actions in detail.
                                                             (line 1338)
* configtweak:                           Semantic Actions in detail.
                                                             (line 1347)
* contents1:                             Semantic Actions in detail.
                                                             (line 1240)
* contents2:                             Semantic Actions in detail.
                                                             (line 1247)
* contents3:                             Semantic Actions in detail.
                                                             (line 1249)
* contents4:                             Semantic Actions in detail.
                                                             (line 1251)
* contentsheader:                        Semantic Actions in detail.
                                                             (line 1253)
* contracted:                            Semantic Actions in detail.
                                                             (line 1360)
* document:                              Semantic Actions in detail.
                                                             (line 1258)
* footer:                                Semantic Actions in detail.
                                                             (line 1362)
* generic:                               Semantic Actions in detail.
                                                             (line 1369)
* graphic:                               Semantic Actions in detail.
                                                             (line 1380)
* heading1:                              Semantic Actions in detail.
                                                             (line 1260)
* heading2:                              Semantic Actions in detail.
                                                             (line 1262)
* heading3:                              Semantic Actions in detail.
                                                             (line 1264)
* heading4:                              Semantic Actions in detail.
                                                             (line 1266)
* htmllink:                              Semantic Actions in detail.
                                                             (line 1385)
* htmltarget:                            Semantic Actions in detail.
                                                             (line 1391)
* italicx:                               Semantic Actions in detail.
                                                             (line 1397)
* linespacing:                           Semantic Actions in detail.
                                                             (line 1405)
* maction:                               Semantic Actions in detail.
                                                             (line 1414)
* maligngroup:                           Semantic Actions in detail.
                                                             (line 1423)
* malignmark:                            Semantic Actions in detail.
                                                             (line 1425)
* math:                                  Semantic Actions in detail.
                                                             (line 1427)
* menclose:                              Semantic Actions in detail.
                                                             (line 1439)
* merror:                                Semantic Actions in detail.
                                                             (line 1441)
* mfenced:                               Semantic Actions in detail.
                                                             (line 1443)
* mfrac:                                 Semantic Actions in detail.
                                                             (line 1445)
* mglyph:                                Semantic Actions in detail.
                                                             (line 1447)
* mi:                                    Semantic Actions in detail.
                                                             (line 1449)
* mlabeledtr:                            Semantic Actions in detail.
                                                             (line 1451)
* mmultiscripts:                         Semantic Actions in detail.
                                                             (line 1453)
* mn:                                    Semantic Actions in detail.
                                                             (line 1455)
* mo:                                    Semantic Actions in detail.
                                                             (line 1457)
* mover:                                 Semantic Actions in detail.
                                                             (line 1459)
* mpadded:                               Semantic Actions in detail.
                                                             (line 1461)
* mphantom:                              Semantic Actions in detail.
                                                             (line 1463)
* mprescripts:                           Semantic Actions in detail.
                                                             (line 1465)
* mroot:                                 Semantic Actions in detail.
                                                             (line 1467)
* mrow:                                  Semantic Actions in detail.
                                                             (line 1472)
* ms:                                    Semantic Actions in detail.
                                                             (line 1478)
* mspace:                                Semantic Actions in detail.
                                                             (line 1480)
* msqrt:                                 Semantic Actions in detail.
                                                             (line 1485)
* mstyle:                                Semantic Actions in detail.
                                                             (line 1487)
* msub:                                  Semantic Actions in detail.
                                                             (line 1491)
* msubsup:                               Semantic Actions in detail.
                                                             (line 1493)
* msup:                                  Semantic Actions in detail.
                                                             (line 1495)
* mtable:                                Semantic Actions in detail.
                                                             (line 1497)
* mtd:                                   Semantic Actions in detail.
                                                             (line 1505)
* mtext:                                 Semantic Actions in detail.
                                                             (line 1513)
* mtr:                                   Semantic Actions in detail.
                                                             (line 1515)
* munder:                                Semantic Actions in detail.
                                                             (line 1525)
* munderover:                            Semantic Actions in detail.
                                                             (line 1527)
* music:                                 Semantic Actions in detail.
                                                             (line 1529)
* newpage:                               Semantic Actions in detail.
                                                             (line 1534)
* no:                                    Semantic Actions in detail.
                                                             (line 1541)
* none:                                  Semantic Actions in detail.
                                                             (line 1549)
* note:                                  Semantic Actions.   (line 1985)
* noteref:                               Semantic Actions.   (line 2001)
* notesdescription:                      Semantic Actions.   (line 2033)
* notesheader:                           Semantic Actions.   (line 2018)
* notranslate:                           Semantic Actions in detail.
                                                             (line 1553)
* pagenum:                               Semantic Actions in detail.
                                                             (line 1561)
* para:                                  Semantic Actions in detail.
                                                             (line 1268)
* reverse:                               Semantic Actions in detail.
                                                             (line 1573)
* righthandpage:                         Semantic Actions in detail.
                                                             (line 1580)
* runninghead:                           Semantic Actions in detail.
                                                             (line 1588)
* semantics:                             Semantic Actions in detail.
                                                             (line 1596)
* skip:                                  Semantic Actions in detail.
                                                             (line 1601)
* softreturn:                            Semantic Actions in detail.
                                                             (line 1606)
* uncontracted:                          Semantic Actions in detail.
                                                             (line 1611)
* underlinex:                            Semantic Actions in detail.
                                                             (line 1616)

Style Index
***********

* Menu:

* boxline:                               style.               (line 898)
* contents1:                             style.               (line 826)
* contents2:                             style.               (line 838)
* contents3:                             style.               (line 845)
* contents4:                             style.               (line 852)
* contentsheader:                        style.               (line 813)
* document:                              style.               (line 700)
* heading1:                              style.               (line 859)
* heading2:                              style.               (line 868)
* heading3:                              style.               (line 876)
* heading4:                              style.               (line 883)
* para:                                  style.               (line 891)

Function Index
**************

* Menu:

* lbu_backTranslateFile:                 lbu_backTranslateFile.
                                                             (line 2668)
* lbu_free:                              lbu_free.           (line 2689)
* lbu_initialize:                        lbu_initialize.     (line 2563)
* lbu_translateFile:                     lbu_translateFile.  (line 2625)
* lbu_translateString:                   lbu_translateString.
                                                             (line 2586)
* lbu_translateTextFile:                 lbu_translateTextFile.
                                                             (line 2648)
* lbu_version:                           lbu_version.        (line 2554)

Program Index
*************

* Menu:

* file2brl:                              Transcribing XML files with file2brl.
                                                              (line 144)

Concept Index
*************

* Menu:

* Macros:                                Using Macros.       (line 1702)
* Namespaces:                            namespaces.         (line 1650)
* XPath Expressions:                     Using XPath Expressions.
                                                             (line 1660)

