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# doctools::idx::parse(n) 1 tcllib "Documentation tools"

## Name

doctools::idx::parse - Parsing text in docidx format

## Synopsis

- package require doctools::idx::parse ?0.1?
- package require Tcl 8.4
- package require doctools::idx::structure
- package require doctools::msgcat
- package require doctools::tcl::parse
- package require fileutil
- package require logger
- package require snit
- package require struct::list
- package require struct::stack

- ::doctools::idx::parse text text
- ::doctools::idx::parse file path
- ::doctools::idx::parse includes
- ::doctools::idx::parse include add path
- ::doctools::idx::parse include remove path
- ::doctools::idx::parse include clear
- ::doctools::idx::parse vars
- ::doctools::idx::parse var set name value
- ::doctools::idx::parse var unset name
- ::doctools::idx::parse var clear ?pattern?

## Description

This package provides commands to parse text written in the docidx markup language and convert it into the canonical serialization of the keyword index encoded in the text. See the section Keyword index serialization format for specification of their format.

This is an internal package of doctools, for use by the higher level packages handling docidx documents.

## API

::doctools::idx::parse text text

  The command takes the string contained in text and parses it under the assumption that it contains a document written using the docidx markup language. An error is thrown if this assumption is found to be false. The format of these errors is described in section Parse errors.

  When successful the command returns the canonical serialization of the keyword index which was encoded in the text. See the section Keyword index serialization format for specification of that format.

::doctools::idx::parse file path

  The same as text, except that the text to parse is read from the file specified by path.

::doctools::idx::parse includes

  This method returns the current list of search paths used when looking for include files.

::doctools::idx::parse include add path

  This method adds the path to the list of paths searched when looking for an include file. The call is ignored if the path is already in the list of paths. The method returns the empty string as its result.

::doctools::idx::parse include remove path

  This method removes the path from the list of paths searched when looking for an include file. The call is ignored if the path is not contained in the list of paths. The method returns the empty string as its result.

::doctools::idx::parse include clear

  This method clears the list of search paths for include files.

::doctools::idx::parse vars

  This method returns a dictionary containing the current set of predefined variables known to the vset markup command during processing.

::doctools::idx::parse var set name value

  This method adds the variable name to the set of predefined variables known to the vset markup command during processing, and gives it the specified value. The method returns the empty string as its result.

::doctools::idx::parse var unset name

  This method removes the variable name from the set of predefined variables known to the vset markup command during processing. The method returns the empty string as its result.

::doctools::idx::parse var clear ?pattern?

  This method removes all variables matching the pattern from the set of predefined variables known to the vset markup command during processing. The method returns the empty string as its result.

  The pattern matching is done with string match, and the default pattern used when none is specified, is *.

## Parse errors

The format of the parse error messages thrown when encountering violations of the docidx markup syntax is human readable and not intended for processing by machines. As such it is not documented.

However, the errorCode attached to the message is machine-readable and has the following format:

1. The error code will be a list, each element describing a single error found in the input. The list has at least one element, possibly more.

2. Each error element will be a list containing six strings describing an error in detail. The strings will be

   1. The path of the file the error occured in. This may be empty.

   2. The range of the token the error was found at. This range is a two-element list containing the offset of the first and last character in the range, counted from the beginning of the input (file). Offsets are counted from zero.

   3. The line the first character after the error is on. Lines are counted from one.

   4. The column the first character after the error is at. Columns are counted from zero.

   5. The message code of the error. This value can be used as argument to msgcat::mc to obtain a localized error message, assuming that the application had a suitable call of doctools::msgcat::init to initialize the necessary message catalogs (See package doctools::msgcat).

   6. A list of details for the error, like the markup command involved. In the case of message code docidx/include/syntax this value is the set of errors found in the included file, using the format described here.

## [docidx] notation of keyword indices

The docidx format for keyword indices, also called the docidx markup language, is too large to be covered in single section. The interested reader should start with the document

1. docidx language introduction

and then proceed from there to the formal specifications, i.e. the documents

1. docidx language syntax and

2. docidx language command reference.

to get a thorough understanding of the language.

## 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, refering to one of the documents the index was made for.

     url

       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.

## Keywords

docidx, doctools, lexer, parser

## Category

Documentation tools

## Copyright

Copyright © 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>