Provided by: tcllib_1.17-dfsg-1_all 
NAME
doctools::toc::export::json - JSON export plugin
SYNOPSIS
package require Tcl 8.4
package require doctools::toc::export::json ?0.1?
package require textutil::adjust
export serial configuration
_________________________________________________________________________________________________
DESCRIPTION
This package implements the doctools table of contents export plugin for the generation of
JSON markup.
This is an internal package of doctools, for use by the higher level management packages
handling tables of contents, especially doctools::toc::export, the export manager.
Using it from a regular interpreter is possible, however only with contortions, and is not
recommended. The proper way to use this functionality is through the package
doctools::toc::export and the export manager objects it provides.
API
The API provided by this package satisfies the specification of the doctoc export plugin
API version 2.
export serial configuration
This command takes the canonical serialization of a table of contents, as specified
in section ToC serialization format, and contained in serial, the configuration, a
dictionary, and generates JSON markup encoding the table. The created string is
then returned as the result of the command.
JSON NOTATION OF TABLES OF CONTENTS
The JSON format used for tables of contents is a direct translation of the ToC
serialization format, mapping Tcl dictionaries as JSON objects and Tcl lists as JSON
arrays. For example, the Tcl serialization
doctools::toc {
items {
{reference {
desc {DocTools - Tables of Contents}
id introduction.man
label doctools::toc::introduction
}}
{division {
id processing.man
items {
{reference {
desc {doctoc serialization utilities}
id structure.man
label doctools::toc::structure
}}
{reference {
desc {Parsing text in doctoc format}
id parse.man
label doctools::toc::parse
}}
}
label Processing
}}
}
label {Table of Contents}
title TOC
}
is equivalent to the JSON string
{
"doctools::toc" : {
"items" : [{
"reference" : {
"desc" : "DocTools - Tables of Contents",
"id" : "introduction.man",
"label" : "doctools::toc::introduction"
}
},{
"division" : {
"id" : "processing.man",
"items" : [{
"reference" : {
"desc" : "doctoc serialization utilities",
"id" : "structure.man",
"label" : "doctools::toc::structure"
}
},{
"reference" : {
"desc" : "Parsing text in doctoc format",
"id" : "parse.man",
"label" : "doctools::toc::parse"
}
}],
"label" : "Processing"
}
}],
"label" : "Table of Contents",
"title" : "TOC"
}
}
CONFIGURATION
The JSON export plugin recognizes the following configuration variables and changes its
behaviour as they specify.
boolean indented
If this flag is set the plugin will break the generated JSON code across lines and
indent it according to its inner structure, with each key of a dictionary on a
separate line.
If this flag is not set (the default), the whole JSON object will be written on a
single line, with minimum spacing between all elements.
boolean aligned
If this flag is set the generator ensures that the values for the keys in a
dictionary are vertically aligned with each other, for a nice table effect. To make
this work this also implies that indented is set.
If this flag is not set (the default), the output is formatted as per the value of
indented, without trying to align the values for dictionary keys.
Note that this plugin ignores the standard configuration variables user, format, file, and
map and their values.
TOC SERIALIZATION FORMAT
Here we specify the format used by the doctools v2 packages to serialize tables of
contents as immutable values for transport, comparison, etc.
We distinguish between regular and canonical serializations. While a table of contents
may have more than one regular serialization only exactly one of them will be canonical.
regular serialization
[1] The serialization of any table of contents is a nested Tcl dictionary.
[2] This dictionary holds a single key, doctools::toc, and its value. This value
holds the contents of the table of contents.
[3] The contents of the table of contents are a Tcl dictionary holding the title
of the table of contents, a label, and its elements. The relevant keys and
their values are
title The value is a string containing the title of the table of contents.
label The value is a string containing a label for the table of contents.
items The value is a Tcl list holding the elements of the table, in the
order they are to be shown.
Each element is a Tcl list holding the type of the item, and its
description, in this order. An alternative description would be that
it is a Tcl dictionary holding a single key, the item type, mapped to
the item description.
The two legal item types and their descriptions are
reference
This item describes a single entry in the table of contents,
referencing a single document. To this end its value is a Tcl
dictionary containing an id for the referenced document, a
label, and a longer textual description which can be
associated with the entry. The relevant keys and their values
are
id The value is a string containing the id of the document
associated with the entry.
label The value is a string containing a label for this
entry. This string also identifies the entry, and no
two entries (references and divisions) in the
containing list are allowed to have the same label.
desc The value is a string containing a longer description
for this entry.
division
This item describes a group of entries in the table of
contents, inducing a hierarchy of entries. To this end its
value is a Tcl dictionary containing a label for the group, an
optional id to a document for the whole group, and the list of
entries in the group. The relevant keys and their values are
id The value is a string containing the id of the document
associated with the whole group. This key is optional.
label The value is a string containing a label for the group.
This string also identifies the entry, and no two
entries (references and divisions) in the containing
list are allowed to have the same label.
items The value is a Tcl list holding the elements of the
group, in the order they are to be shown. This list
has the same structure as the value for the keyword
items used to describe the whole table of contents, see
above. This closes the recusrive definition of the
structure, with divisions holding the same type of
elements as the whole table of contents, including
other divisions.
canonical serialization
The canonical serialization of a table of contents has the format as specified in
the previous item, and then additionally satisfies the constraints below, which
make it unique among all the possible serializations of this table of contents.
[1] The keys found in all the nested Tcl dictionaries are sorted in ascending
dictionary order, as generated by Tcl's builtin command lsort -increasing
-dict.
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain bugs and other
problems. Please report such in the category doctools of the Tcllib Trackers
[http://core.tcl.tk/tcllib/reportlist]. Please also report any ideas for enhancements you
may have for either package and/or documentation.
KEYWORDS
JSON, doctools, export, serialization, table of contents, toc
CATEGORY
Text formatter plugin
COPYRIGHT
Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>