Provided by: tcllib_1.21+dfsg-1_all bug

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) 2009-2019 Andreas Kupries <andreas_kupries@users.sourceforge.net>