[comment {-*- tcl -*- doctools manpage}]
[manpage_begin doctools_lang_syntax n 1.0]
[see_also doctools_intro]
[see_also doctools_lang_cmdref]
[see_also doctools_lang_faq]
[see_also doctools_lang_intro]
[keywords {doctools commands}]
[keywords {doctools language}]
[keywords {doctools markup}]
[keywords {doctools syntax}]
[keywords markup]
[keywords {semantic markup}]
[copyright {2007 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
[moddesc   {Documentation tools}]
[titledesc {doctools language syntax}]
[category  {Documentation tools}]
[description]
[para]

This document contains the formal specification of the syntax of the
doctools markup language, version 1 in Backus-Naur-Form. This document
is intended to be a reference, complementing the
[term {doctools language command reference}].

A beginner should read the much more informally written
[term {doctools language introduction}] first before trying to
understand either this document or the command reference.

[section Fundamentals]

In the broadest terms possible the [term {doctools markup language}]
is LaTeX-like, instead of like SGML and similar languages. A document
written in this language consists primarily of text, with markup
commands embedded into it.

[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 {doctools 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 doctools
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.
[enum]
The construct LIST_BEGIN<X> stands for the markup command
[cmd list_begin] with [const X] as its type argument.
[list_end]

The syntax:

[example {
manpage = defs
          MANPAGE_BEGIN
          header
          DESCRIPTION
          body
          MANPAGE_END
          { <WHITE> }

defs    = { INCLUDE | VSET | <WHITE> }

header  = { TITLEDESC | MODDESC | COPYRIGHT | REQUIRE | defs | xref }

xref    = KEYWORDS | SEE_ALSO | CATEGORY

body    = paras { SECTION    sbody  }
sbody   = paras { SUBSECTION ssbody }
ssbody  = paras

paras   = tblock { (PARA | NL) tblock }

tblock  = { <TEXT> | defs | markup | xref | an_example | a_list }

markup  = ARG     | CLASS | CMD     | CONST     | EMPH   | FILE
        | FUN     | LB    | METHOD  | NAMESPACE | OPT    | OPTION
        | PACKAGE | RB    | SECTREF | STRONG    | SYSCMD | TERM
        | TYPE    | URI   | USAGE   | VAR       | WIDGET

example = EXAMPLE
        | EXAMPLE_BEGIN extext EXAMPLE_END

extext  = { <TEXT> | defs | markup }

a_list  = LIST_BEGIN<arguments>   argd_list   LIST_END
        | LIST_BEGIN<commands>    cmdd_list   LIST_END
        | LIST_BEGIN<definitions> def_list    LIST_END
        | LIST_BEGIN<enumerated>  enum_list   LIST_END
        | LIST_BEGIN<itemized>    item_list   LIST_END
        | LIST_BEGIN<options>     optd_list   LIST_END
        | LIST_BEGIN<tkoptions>   tkoptd_list LIST_END

argd_list   = [ <WHITE> ] { ARG_DEF      paras }
cmdd_list   = [ <WHITE> ] { CMD_DEF      paras }
def_list    = [ <WHITE> ] { (DEF|CALL)   paras }
enum_list   = [ <WHITE> ] { ENUM         paras }
item_list   = [ <WHITE> ] { ITEM         paras }
optd_list   = [ <WHITE> ] { OPT_DEF      paras }
tkoptd_list = [ <WHITE> ] { TKOPTION_DEF paras }
}]

[vset CATEGORY doctools]
[include ../doctools2base/include/feedback.inc]
[manpage_end]