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doctools::idx::import::json(n) 0.1 tcllib "Documentation tools"


doctools::idx::import::json - JSON import plugin

Table Of Contents


  • package require Tcl 8.4
  • package require doctools::idx::import::json ?0.1?
  • package require doctools::idx::structure
  • package require json


This package implements the doctools keyword index import plugin for the parsing of JSON markup.

This is an internal package of doctools, for use by the higher level management packages handling keyword indices, especially doctools::idx::import, the import 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::import and the import manager objects it provides.


The API provided by this package satisfies the specification of the docidx import plugin API version 2.

import string configuration

This command takes the string and parses it as JSON markup encoding a keyword index, in the context of the specified configuration (a dictionary). The result of the command is the canonical serialization of that keyword index, in the form specified in section Keyword index serialization format.

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"      : ""

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


    The value is a string containing the title of the index.


    The value is a string containing a label for the index.


    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.


    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,


    The identifier of the reference is interpreted as symbolic file name, refering to one of the documents the index was made for.


    The identifier of the reference is interpreted as an url, refering 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. Please also report any ideas for enhancements you may have for either package and/or documentation.


JSON, deserialization, doctools, import, index


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