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NAME

       doctools::toc::export - Exporting tables of contents

SYNOPSIS

       package require doctools::toc::export  ?0.1?

       package require Tcl  8.4

       package require doctools::config

       package require doctools::toc::structure

       package require snit

       package require pluginmgr

       ::doctools::toc::export objectName

       objectName method ?arg arg ...?

       objectName destroy

       objectName export serial serial ?format?

       objectName export object object ?format?

       objectName config names

       objectName config get

       objectName config set name ?value?

       objectName config unset pattern...

       export serial configuration

_________________________________________________________________

DESCRIPTION

       This  package  provides a class to manage the plugins for the export of tables of contents
       to other formats, i.e. their conversion to, for example doctoc, HTML, etc.

       This is one of the three public pillars the management of tables of contents  resides  on.
       The other two pillars are

       [1]    Importing tables of contents, and

       [2]    Holding tables of contents

       For  information  about the Concepts of tables of contents, and their parts, see the same-
       named section.  For information about the data structure which is the major input  to  the
       manager objects provided by this package see the section ToC serialization format.

       The  plugin  system of our class is based on the package pluginmgr, and configured to look
       for plugins using

       [1]    the environment variable DOCTOOLS_TOC_EXPORT_PLUGINS,

       [2]    the environment variable DOCTOOLS_TOC_PLUGINS,

       [3]    the environment variable DOCTOOLS_PLUGINS,

       [4]    the path "~/.doctools/toc/export/plugin"

       [5]    the path "~/.doctools/toc/plugin"

       [6]    the path "~/.doctools/plugin"

       [7]    the path "~/.doctools/toc/export/plugins"

       [8]    the path "~/.doctools/toc/plugins"

       [9]    the path "~/.doctools/plugins"

       [10]   the registry entry "HKEY_CURRENT_USER\SOFTWARE\DOCTOOLS\TOC\EXPORT\PLUGINS"

       [11]   the registry entry "HKEY_CURRENT_USER\SOFTWARE\DOCTOOLS\TOC\PLUGINS"

       [12]   the registry entry "HKEY_CURRENT_USER\SOFTWARE\DOCTOOLS\PLUGINS"

       The last three are used only when the package  is  run  on  a  machine  using  Windows(tm)
       operating system.

       The whole system is delivered with six predefined export plugins, namely

       doctoc See doctoc export plugin for details.

       html   See html export plugin for details.

       json   See json export plugin for details.

       nroff  See nroff export plugin for details.

       text   See text export plugin for details.

       wiki   See wiki export plugin for details.

       Readers  wishing  to  write  their own export plugin for some format, i.e.  plugin writers
       reading and understanding the section containing the Export plugin API v2 reference is  an
       absolute  necessity,  as it specifies the interaction between this package and its plugins
       in detail.

CONCEPTS

       [1]    A table of contents consists of a (possibly empty) list of elements.

       [2]    Each element in the list is identified by its label.

       [3]    Each element is either a reference, or a division.

       [4]    Each reference has an associated document, identified  by  a  symbolic  id,  and  a
              textual description.

       [5]    Each division may have an associated document, identified by a symbolic id.

       [6]    Each  division  consists consists of a (possibly empty) list of elements, with each
              element following the rules as specified in item 2 and above.

       A few notes

       [1]    The above rules span up a tree of elements, with references as the leaf nodes,  and
              divisions  as  the inner nodes, and each element representing an entry in the whole
              table of contents.

       [2]    The identifying labels of any element E are unique within their division (or  toc),
              and  the  full  label  of  any element E is the list of labels for all nodes on the
              unique path from the root of the tree to E, including E.

API

   PACKAGE COMMANDS
       ::doctools::toc::export objectName
              This command creates a new export manager object with  an  associated  Tcl  command
              whose  name  is  objectName. This object command is explained in full detail in the
              sections Object command and Object methods. The  object  command  will  be  created
              under  the  current  namespace if the objectName is not fully qualified, and in the
              specified namespace otherwise.

   OBJECT COMMAND
       All objects created by the ::doctools::toc::export  command  have  the  following  general
       form:

       objectName method ?arg arg ...?
              The  method  method and its arg'uments determine the exact behavior of the command.
              See section Object methods for the detailed specifications.

   OBJECT METHODS
       objectName destroy
              This method destroys the object it is invoked for.

       objectName export serial serial ?format?
              This method takes the canonical serialization of a  table  of  contents  stored  in
              serial  and  converts  it  to the specified format, using the export plugin for the
              format. An error is thrown if no plugin could be found for the format.  The  string
              generated by the conversion process is returned as the result of this method.

              If no format is specified the method defaults to doctoc.

              The  specification of what a canonical serialization is can be found in the section
              ToC serialization format.

              The plugin has to conform to the interface specified in section Export  plugin  API
              v2 reference.

       objectName export object object ?format?
              This  method  is  a convenient wrapper around the export serial method described by
              the previous item.  It expects that  object  is  an  object  command  supporting  a
              serialize  method  returning the canonical serialization of a table of contents. It
              invokes that method, feeds the result into export serial and returns the  resulting
              string as its own result.

       objectName config names
              This  method  returns  a  list  containing the names of all configuration variables
              currently known to the object.

       objectName config get
              This  method  returns  a  dictionary  containing  the  names  and  values  of   all
              configuration variables currently known to the object.

       objectName config set name ?value?
              This method sets the configuration variable name to the specified value and returns
              the new value of the variable.

              If no value is specified it simply returns the current value, without changing it.

              Note that while the user can set the predefined configuration  variables  user  and
              format doing so will have no effect, these values will be internally overriden when
              invoking an import plugin.

       objectName config unset pattern...
              This  method  unsets  all  configuration  variables  matching  the  specified  glob
              patterns.  If  no  pattern  is  specified  it  will  unset  all  currently  defined
              configuration variables.

EXPORT PLUGIN API V2 REFERENCE

       Plugins are what this package uses to manage the support for any output format beyond  the
       ToC  serialization format. Here we specify the API the objects created by this package use
       to interact with their plugins.

       A plugin for this package has to follow the rules listed below:

       [1]    A plugin is a package.

       [2]    The name of a plugin package has the form doctools::toc::export::FOO, where FOO  is
              the  name  of the format the plugin will generate output for. This name is also the
              argument to provide to the various export methods of export manager objects to  get
              a string encoding a table of contents in that format.

       [3]    The plugin can expect that the package doctools::toc::export::plugin is present, as
              indicator that it was invoked from a genuine plugin manager.

       [4]    A plugin has to provide one command, with the signature shown below.

              export serial configuration
                     Whenever an export manager of doctools::toc has to  generate  output  for  a
                     table of contents it will invoke this command.

                     string serial
                            This  argument  will contain the canonical serialization of the table
                            of contents for which to generate the output.  The  specification  of
                            what  a  canonical  serialization  is can be found in the section ToC
                            serialization format.

                     dictionary configuration
                            This argument will contain the current configuration to apply to  the
                            generation, as a dictionary mapping from variable names to values.

                            The  following  configuration variables have a predefined meaning all
                            plugins have to obey, although they can ignore  this  information  at
                            their  discretion. Any other other configuration variables recognized
                            by a plugin will be described in the manpage for that plugin.

                            user   This variable is expected to contain  the  name  of  the  user
                                   owning the process invoking the plugin.

                            format This  variable  is  expected to contain the name of the format
                                   whose plugin is invoked.

                            file   This variable, if defined by the user of the table  object  is
                                   expected  to  contain the name of the input file for which the
                                   plugin is generating its output for.

                            map    This variable, if defined by the user of the table  object  is
                                   expected   to  contain  a  dictionary  mapping  from  symbolic
                                   document ids used in the table entries  to  actual  paths  (or
                                   urls).  A plugin has to be able to handle the possibility that
                                   a document id is without entry in this mapping.

       [5]    A single usage cycle of a plugin consists of the invokations of the command export.
              This  call  has to leave the plugin in a state where another usage cycle can be run
              without problems.

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 SF Trackers
       [http://sourceforge.net/tracker/?group_id=12883].   Please  also  report  any  ideas   for
       enhancements you may have for either package and/or documentation.

KEYWORDS

       HTML,  conversion,  doctoc,  documentation, export, formatting, generation, json, manpage,
       markup, nroff, plugin, reference, table, table of contents, tcler's wiki, text, url, wiki

CATEGORY

       Documentation tools

COPYRIGHT

       Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>