'\"
'\" Generated from file 'plugin\&.inc' by tcllib/doctools with format 'nroff'
'\" Copyright (c) 2009-2019 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>
'\"
.TH "doctools::idx::export::json" n 0\&.2 tcllib "Documentation tools"
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.BS
.SH NAME
doctools::idx::export::json \- JSON export plugin
.SH SYNOPSIS
package require \fBTcl 8\&.5 9\fR
.sp
package require \fBdoctools::idx::export::json ?0\&.2?\fR
.sp
package require \fBtextutil::adjust\fR
.sp
\fBexport\fR \fIserial\fR \fIconfiguration\fR
.sp
.BE
.SH DESCRIPTION
This package implements the doctools keyword index export plugin for
the generation of JSON markup\&.
.PP
This is an internal package of doctools, for use by the higher level
management packages handling keyword indices, especially \fBdoctools::idx::export\fR, the export manager\&.
.PP
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
\fBdoctools::idx::export\fR and the export manager objects it
provides\&.
.SH API
The API provided by this package satisfies the specification of the
docidx export plugin API version 2\&.
.TP
\fBexport\fR \fIserial\fR \fIconfiguration\fR
This command takes the canonical serialization of a keyword index, as
specified in section \fBKeyword index serialization format\fR,
and contained in \fIserial\fR, the \fIconfiguration\fR, a dictionary,
and generates JSON markup encoding the index\&.
The created string is then returned as the result of the command\&.
.PP
.SH "JSON NOTATION OF KEYWORD INDICES"
The JSON format used for keyword indices is a direct translation of
the \fBKeyword index serialization format\fR, mapping Tcl
dictionaries as JSON objects and Tcl lists as JSON arrays\&.
For example, the Tcl serialization
.CS


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 {}
}

.CE
is equivalent to the JSON string
.CS


{
    "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"      : ""
    }
}

.CE
.SH CONFIGURATION
The JSON export plugin recognizes the following configuration
variables and changes its behaviour as they specify\&.
.TP
boolean \fIindented\fR
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\&.
.sp
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\&.
.TP
boolean \fIaligned\fR
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 \fBindented\fR
is set\&.
.sp
If this flag is not set (the default), the output is formatted as per
the value of \fBindented\fR, without trying to align the values for
dictionary keys\&.
.PP
\fINote\fR that this plugin ignores the standard configuration
variables \fBuser\fR, \fBformat\fR, \fBfile\fR, and \fBmap\fR and
their values\&.
.SH "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\&.
.PP
We distinguish between \fIregular\fR and \fIcanonical\fR
serializations\&. While a keyword index may have more than one regular
serialization only exactly one of them will be \fIcanonical\fR\&.
.PP
.TP
regular serialization
.RS
.IP [1]
An index serialization is a nested Tcl dictionary\&.
.IP [2]
This dictionary holds a single key, \fBdoctools::idx\fR, and its
value\&. This value holds the contents of the index\&.
.IP [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
.RS
.TP
\fBtitle\fR
The value is a string containing the title of the index\&.
.TP
\fBlabel\fR
The value is a string containing a label for the index\&.
.TP
\fBkeywords\fR
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\&.
.sp
Any reference identifier used in these lists has to exist as a key in
the \fBreferences\fR dictionary, see the next item for its
definition\&.
.TP
\fBreferences\fR
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\&.
.sp
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 \fBkeywords\fR dictionary, see previous item for its
definition\&.
.RE
.IP [4]
The \fItype\fR of a reference can be one of two values,
.RS
.TP
\fBmanpage\fR
The identifier of the reference is interpreted as symbolic file name,
referring to one of the documents the index was made for\&.
.TP
\fBurl\fR
The identifier of the reference is interpreted as an url, referring to
some external location, like a website, etc\&.
.RE
.RE
.TP
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\&.
.RS
.IP [1]
The keys found in all the nested Tcl dictionaries are sorted in
ascending dictionary order, as generated by Tcl's builtin command
\fBlsort -increasing -dict\fR\&.
.IP [2]
The references listed for each keyword of the index, if any, are
listed in ascending dictionary order of their \fIlabels\fR, as
generated by Tcl's builtin command \fBlsort -increasing -dict\fR\&.
.RE
.PP
.SH "BUGS, IDEAS, FEEDBACK"
This document, and the package it describes, will undoubtedly contain
bugs and other problems\&.
Please report such in the category \fIdoctools\fR of the
\fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&.
Please also report any ideas for enhancements you may have for either
package and/or documentation\&.
.PP
When proposing code changes, please provide \fIunified diffs\fR,
i\&.e the output of \fBdiff -u\fR\&.
.PP
Note further that \fIattachments\fR are strongly preferred over
inlined patches\&. Attachments can be made by going to the \fBEdit\fR
form of the ticket immediately after its creation, and then using the
left-most button in the secondary navigation bar\&.
.SH KEYWORDS
JSON, doctools, export, index, serialization
.SH CATEGORY
Text formatter plugin
.SH COPYRIGHT
.nf
Copyright (c) 2009-2019 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>

.fi
