[comment {-*- tcl -*- doctools manpage}]
[manpage_begin docidx_lang_syntax n 1.0]
[see_also docidx_intro]
[see_also docidx_lang_cmdref]
[see_also docidx_lang_faq]
[see_also docidx_lang_intro]
[keywords {docidx commands}]
[keywords {docidx language}]
[keywords {docidx markup}]
[keywords {docidx syntax}]
[keywords markup]
[keywords {semantic markup}]
[copyright {2007-2009 Andreas Kupries <[email protected]>}]
[moddesc {Documentation tools}]
[titledesc {docidx language syntax}]
[category {Documentation tools}]
[description]
[para]
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
[term {docidx language command reference}].
A beginner should read the much more informally written
[term {docidx language introduction}] first before trying to
understand either this document or the command reference.
[section Fundamentals]
In the broadest terms possible the [term {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.
[para]
Each markup command is a just Tcl command surrounded by a matching
pair of [const [lb]] and [const [rb]]. Which commands are available,
and their arguments, i.e. syntax is specified in the
[term {docidx language command reference}].
[para]
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.
[section {Lexical definitions}]
In the syntax rules listed in the next section
[list_begin enumerated]
[enum]
<TEXT> stands for all text except markup commands.
[enum]
Any XXX stands for the markup command [lb]xxx[rb] including its
arguments. Each markup command is a Tcl command surrounded by a
matching pair of [const [lb]] and [const [rb]]. Inside of these
delimiters the usual rules for a Tcl command apply with regard to word
quotation, nested commands, continuation lines, etc.
[enum]
<WHITE> stands for all text consisting only of spaces, newlines,
tabulators and the [cmd comment] markup command.
[list_end]
[section Syntax]
The rules listed here specify only the syntax of docidx documents. The
lexical level of the language was covered in the previous section.
[para]
Regarding the syntax of the (E)BNF itself
[list_begin enumerated]
[enum]
The construct { X } stands for zero or more occurrences of X.
[enum]
The construct [lb] X [rb] stands for zero or one occurrence of X.
[list_end]
The syntax:
[example {
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.
[list_begin enumerated]
[enum]
The arguments of all markup commands have to be plain text, and/or text
markup commands, i.e. one of
[list_begin enumerated]
[enum][cmd lb],
[enum][cmd rb], or
[enum][cmd vset] (1-argument form).
[list_end]
[list_end]
[vset CATEGORY doctools]
[include ../doctools2base/include/feedback.inc]
[manpage_end]
