NAME

       docidx_lang_syntax - docidx language syntax

DESCRIPTION

       This  document  contains  the  formal  specification  of  the  syntax of the docidx markup
       language, version 1 in Backus-Naur-Form. This document is  intended  to  be  a  reference,
       complementing the docidx language command reference.  A beginner should read the much more
       informally written docidx language introduction first before trying to  understand  either
       this document or the command reference.

FUNDAMENTALS

       In  the  broadest  terms  possible  the  docidx  markup  language is like SGML and similar
       languages. A document written in this language consists primarily of markup commands, with
       text embedded into it at some places.

       Each  markup command is a just Tcl command surrounded by a matching pair of [ and ]. Which
       commands are available, and their arguments,  i.e.  syntax  is  specified  in  the  docidx
       language command reference.

       In  this  document  we  specify first the lexeme, and then the syntax, i.e. how we can mix
       text and markup commands with each other.

LEXICAL DEFINITIONS

       In the syntax rules listed in the next section

       [1]    <TEXT> stands for all text except markup commands.

       [2]    Any XXX stands for the markup command [xxx] including its  arguments.  Each  markup
              command  is a Tcl command surrounded by a matching pair of [ and ]. Inside of these
              delimiters the usual rules for a Tcl command apply with regard to  word  quotation,
              nested commands, continuation lines, etc.

       [3]    <WHITE> stands for all text consisting only of spaces, newlines, tabulators and the
              comment markup command.

SYNTAX

       The rules listed here specify only the syntax of docidx documents. The  lexical  level  of
       the language was covered in the previous section.

       Regarding the syntax of the (E)BNF itself

       [1]    The construct { X } stands for zero or more occurrences of X.

       [2]    The construct [ X ] stands for zero or one occurrence of X.

       The syntax:
              index     = defs
              INDEX_BEGIN
              [ contents ]
              INDEX_END
              { <WHITE> }
              defs      = { INCLUDE | VSET | <WHITE> }
              contents  = keyword { keyword }
              keyword   = defs KEY ref { ref }
              ref       = MANPAGE | URL | defs
       At  last a rule we were unable to capture in the EBNF syntax, as it is about the arguments
       of the markup commands, something which is not modeled here.

       [1]    The arguments of all markup commands have to be  plain  text,  and/or  text  markup
              commands, i.e. one of

              [1]    lb,

              [2]    rb, or

              [3]    vset (1-argument form).

BUGS, IDEAS, FEEDBACK

       This  document,  will  undoubtedly contain bugs and other problems.  Please report such in
       the       category       doctools       of       the       Tcllib       SF        Trackers
       [http://sourceforge.net/tracker/?group_id=12883].    Please  also  report  any  ideas  for
       enhancements you may have.

SEE ALSO

       docidx_intro, docidx_lang_cmdref, docidx_lang_faq, docidx_lang_intro

KEYWORDS

       docidx commands, docidx language, docidx markup, docidx syntax, markup, semantic markup

CATEGORY

       Documentation tools

COPYRIGHT

       Copyright (c) 2007-2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>