Provided by: tcllib_1.21+dfsg-1_all 
NAME
doctools::idx::export - Exporting keyword indices
SYNOPSIS
package require doctools::idx::export ?0.2.1?
package require Tcl 8.4
package require struct::map
package require doctools::idx::structure
package require snit
package require pluginmgr
::doctools::idx::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 keyword indices to other formats,
i.e. their conversion to, for example docidx, HTML, etc.
This is one of the three public pillars the management of keyword indices resides on. The other two
pillars are
[1] Importing keyword indices, and
[2] Holding keyword indices
For information about the Concepts of keyword indices, 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 Keyword index 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_IDX_EXPORT_PLUGINS,
[2] the environment variable DOCTOOLS_IDX_PLUGINS,
[3] the environment variable DOCTOOLS_PLUGINS,
[4] the path "~/.doctools/idx/export/plugin"
[5] the path "~/.doctools/idx/plugin"
[6] the path "~/.doctools/plugin"
[7] the path "~/.doctools/idx/export/plugins"
[8] the path "~/.doctools/idx/plugins"
[9] the path "~/.doctools/plugins"
[10] the registry entry "HKEY_CURRENT_USER\SOFTWARE\DOCTOOLS\IDX\EXPORT\PLUGINS"
[11] the registry entry "HKEY_CURRENT_USER\SOFTWARE\DOCTOOLS\IDX\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
docidx See docidx 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 keyword index consists of a (possibly empty) set of keywords.
[2] Each keyword in the set is identified by its name.
[3] Each keyword has a (possibly empty) set of references.
[4] A reference can be associated with more than one keyword.
[5] A reference not associated with at least one keyword is not possible however.
[6] Each reference is identified by its target, specified as either an url or symbolic filename,
depending on the type of reference (url, or manpage).
[7] The type of a reference (url, or manpage) depends only on the reference itself, and not the
keywords it is associated with.
[8] In addition to a type each reference has a descriptive label as well. This label depends only on
the reference itself, and not the keywords it is associated with.
A few notes
[1] Manpage references are intended to be used for references to the documents the index is made for.
Their target is a symbolic file name identifying the document, and export plugins may replace
symbolic with actual file names, if specified.
[2] Url references are intended on the othre hand are inteded to be used for links to anything else,
like websites. Their target is an url.
[3] While url and manpage references share a namespace for their identifiers, this should be no
problem, given that manpage identifiers are symbolic filenames and as such they should never look
like urls, the identifiers for url references.
API
PACKAGE COMMANDS
::doctools::idx::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::idx::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 keyword index 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 docidx.
The specification of what a canonical serialization is can be found in the section Keyword index
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 keyword index. 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 overridden 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 Keyword index
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::idx::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 keyword index in that
format.
[3] The plugin can expect that the package doctools::idx::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::idx has to generate output for an index it will
invoke this command.
string serial
This argument will contain the canonical serialization of the index for which to
generate the output. The specification of what a canonical serialization is can be
found in the section Keyword index 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 index 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 index object is expected to
contain a dictionary mapping from symbolic file names used in the references
of type manpage to actual paths (or urls). A plugin has to be able to handle
the possibility that a symbolic name 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.
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
HTML, conversion, docidx, documentation, export, formatting, generation, index, json, keyword index,
manpage, markup, nroff, plugin, reference, tcler's wiki, text, url, wiki
CATEGORY
Documentation tools
COPYRIGHT
Copyright (c) 2009-2019 Andreas Kupries <andreas_kupries@users.sourceforge.net>