Provided by: tcllib_1.19-dfsg-2_all 
NAME
doctools::idx::export::json - JSON export plugin
SYNOPSIS
package require Tcl 8.4
package require doctools::idx::export::json ?0.1?
package require textutil::adjust
export serial configuration
_________________________________________________________________________________________________
DESCRIPTION
This package implements the doctools keyword index export plugin for the generation of
JSON markup.
This is an internal package of doctools, for use by the higher level management packages
handling keyword indices, especially doctools::idx::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::idx::export and the export manager objects it provides.
API
The API provided by this package satisfies the specification of the docidx export plugin
API version 2.
export serial configuration
This command takes the canonical serialization of a keyword index, as specified in
section Keyword index serialization format, and contained in serial, the
configuration, a dictionary, and generates JSON markup encoding the index. The
created string is then returned as the result of the command.
JSON NOTATION OF KEYWORD INDICES
The JSON format used for keyword indices is a direct translation of the Keyword index
serialization format, mapping Tcl dictionaries as JSON objects and Tcl lists as JSON
arrays. For example, the Tcl serialization
doctools::idx {
label {Keyword Index}
keywords {
changelog {changelog.man cvs.man}
conversion {doctools.man docidx.man doctoc.man apps/dtplite.man mpexpand.man}
cvs cvs.man
}
references {
apps/dtplite.man {manpage dtplite}
changelog.man {manpage doctools::changelog}
cvs.man {manpage doctools::cvs}
docidx.man {manpage doctools::idx}
doctoc.man {manpage doctools::toc}
doctools.man {manpage doctools}
mpexpand.man {manpage mpexpand}
}
title {}
}
is equivalent to the JSON string
{
"doctools::idx" : {
"label" : "Keyword Index",
"keywords" : {
"changelog" : ["changelog.man","cvs.man"],
"conversion" : ["doctools.man","docidx.man","doctoc.man","apps\/dtplite.man","mpexpand.man"],
"cvs" : ["cvs.man"],
},
"references" : {
"apps\/dtplite.man" : ["manpage","dtplite"],
"changelog.man" : ["manpage","doctools::changelog"],
"cvs.man" : ["manpage","doctools::cvs"],
"docidx.man" : ["manpage","doctools::idx"],
"doctoc.man" : ["manpage","doctools::toc"],
"doctools.man" : ["manpage","doctools"],
"mpexpand.man" : ["manpage","mpexpand"]
},
"title" : ""
}
}
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.
KEYWORD INDEX SERIALIZATION FORMAT
Here we specify the format used by the doctools v2 packages to serialize keyword indices
as immutable values for transport, comparison, etc.
We distinguish between regular and canonical serializations. While a keyword index may
have more than one regular serialization only exactly one of them will be canonical.
regular serialization
[1] An index serialization is a nested Tcl dictionary.
[2] This dictionary holds a single key, doctools::idx, and its value. This value
holds the contents of the index.
[3] The contents of the index are a Tcl dictionary holding the title of the
index, a label, and the keywords and references. The relevant keys and their
values are
title The value is a string containing the title of the index.
label The value is a string containing a label for the index.
keywords
The value is a Tcl dictionary, using the keywords known to the index
as keys. The associated values are lists containing the identifiers
of the references associated with that particular keyword.
Any reference identifier used in these lists has to exist as a key in
the references dictionary, see the next item for its definition.
references
The value is a Tcl dictionary, using the identifiers for the
references known to the index as keys. The associated values are
2-element lists containing the type and label of the reference, in
this order.
Any key here has to be associated with at least one keyword, i.e.
occur in at least one of the reference lists which are the values in
the keywords dictionary, see previous item for its definition.
[4] The type of a reference can be one of two values,
manpage
The identifier of the reference is interpreted as symbolic file name,
referring to one of the documents the index was made for.
url The identifier of the reference is interpreted as an url, referring
to some external location, like a website, etc.
canonical serialization
The canonical serialization of a keyword index 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 the keyword index.
[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.
[2] The references listed for each keyword of the index, if any, are listed in
ascending dictionary order of their labels, 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.
When proposing code changes, please provide unified diffs, i.e the output of diff -u.
Note further that attachments are strongly preferred over inlined patches. Attachments can
be made by going to the Edit form of the ticket immediately after its creation, and then
using the left-most button in the secondary navigation bar.
KEYWORDS
JSON, doctools, export, index, serialization
CATEGORY
Text formatter plugin
COPYRIGHT
Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>