[article AutoIndex
    [quickbook 1.4]
    [copyright 2008 John Maddock]
    [license
        Distributed under the Boost Software License, Version 1.0.
        (See accompanying file LICENSE_1_0.txt or copy at
        [@http://www.boost.org/LICENSE_1_0.txt])
    ]
    [authors [Maddock, John]]
    [/last-revision $Date: 2008-11-04 17:11:53 +0000 (Tue, 04 Nov 2008) $]
]

[section:overview Overview]

AutoIndex is a tool for taking the grunt work out of indexing a
Quickbook\/Boostbook\/Docbook document that describes C\/C++ code.

Traditionally, in order to index a Docbook document you would
have to manually add a large amount of `<indexterm>` markup: 
in fact one `<indexterm>` for each occurance of each term to be
indexed.  

Instead AutoIndex will scan one or more C\/C++ header files
and extract all the ['function], ['class], ['macro] and ['typedef] 
names that are defined by those headers, and then insert the 
`<indexterm>`'s into the XML document for you.

AutoIndex creates index entries as follows - for each occurance of 
each search term, it creates two index entries - one has the search term
as the primary index key and the title of the section it appears in as
a subterm, the other has the section title as the main index entry and the
search term as the subentry.  Thus the user has two chances to find what their
looking for, based upon either the section name or the ['function], ['class], ['macro] 
or ['typedef] name.

So for example in Boost.Math the class name `students_t_distribution` has a primary
entry that lists all sections it appears in:

[$../students_t_eg_1.png]

Then those sections also have primary entries, which list all the search terms those
sections contain:

[$../students_t_eg_2.png]

Of course these automated index entries may not be quite
what you're looking for: often you'll get a few spurious entries, a few missing entries,
and a few entries where the section name used as an index entry is less than ideal.
So AutoIndex provides some powerful regular expression based rules that allow you
to add, remove, constrain, or rewrite entries.  Normally just a few lines in
AutoIndex's script file are enough to tailor the output to match the authors
expectations.

AutoIndex also supports multiple indexes (as does Docbook), and since it knows
which search terms are ['function], ['class], ['macro] or ['typedef] names, it
can add the necessary attritubes to the XML so that you can have separate
indexes for each of these different types.  These specialised indexes only contain
entries for the ['function], ['class], ['macro] or ['typedef] names, ['section
names] are never used as primary index terms here, unlike the main "include everything"
index.

Finally, while the Docbook XSL stylesheets create nice indexes complete with page
numbers for PDF output, the HTML indexes look a lot less good, as these use
section titles in place of page numbers... but as AutoIndex uses section titles
as index entries this leads to a lot of repetition, so as an alternative AutoIndex
can be instructed to construct the index itself.  This is faster than using
the XSL stylesheets, and now each index entry is a hyperlink to the 
approprate section:

[$../students_t_eg_3.png]

With internal index generation there is also a helpful navigation bar 
at the start of each Index:

[$../students_t_eg_4.png]

[endsect]

[section:tut Getting Started and Tutorial]

[h4 Step 1: Build the tool]

cd into `tools/auto_index/build` and invoke bjam as:

   bjam release

Optionally pass the name of the compiler toolset you want to use to bjam as well:

   bjam release gcc

[h4 Step 2: Configure Boost.Build]

TODO: we need BoostBook integration!!!

Currently the tool can only be run manually.

[h4 Step 3: Add indexes to your documentation]

To add a single index to a BoostBook\/Docbook document, then add
`<index/>` at the location where you want the index to appear.  The
index will be rendered as a separate section when the documentation
is built.

To add multiple indexes, then give each one a title and set it's
`type` attribute to specify which terms will be included, for example
to place the ['function], ['class], ['macro] or ['typedef] names
indexed by ['auto_index] in separate indexes along with a main
"include everything" index as well, one could add:

  <index type="class_name">
  <title>Class Index</title>
  </index>

  <index type="typedef_name">
  <title>Typedef Index</title>
  </index>

  <index type="function_name">
  <title>Function Index</title>
  </index>

  <index type="macro_name">
  <title>Macro Index</title>
  </index>

  <index/>
  
In quickbook, you add the same markup but enclose it in an escape:

   '''<index/>'''
   
[h4 Step 4: Create the script file]

AutoIndex works by reading a script file that tells it what to index,
at it's simplest it will scan one or more headers for terms that
should be indexed in the documentation.  So for example to scan
"myheader.hpp" the script file would just contain:

   !scan myheader.hpp
   
Or we can recursively scan through directories looking for all
the files to scan whose name matches a particular regular expression:

   !scan-path "../../../../boost/math" ".*\.hpp" true
   
Note how each argument is whitespace separated and can be optionally
enclosed in "double quotes".  The final ['true] argument indicates
that subdirectories in `../../../../boost/math` should be searched
in addition to that directory.

Often the ['scan] or ['scan-path] rules will bring in too many terms
to search for, so we need to be able to exclude terms as well:

   !exclude type
   
Which excludes the term "type" from being indexed.

We can also add terms manually:

   foobar
   
will index occurances of "foobar" and:

   foobar \<\w*(foo|bar)\w*\>
   
will index any whole word containing either "foo" or "bar" within it,
this is useful when you want to index a lot of similar or related
words under one entry, for example:

   reflex
   
Will only index occurances of "reflex" as a whole word, but:

   reflex \<reflex\w*\>
   
will index occurances of "reflex", reflexing" and 
"reflexed" all under the same entry ['reflex].

This inclusion rule can also restict the term to
certain sections, and add an index category that
the term should belong to (so it only appears in certain
indexes).

Finally the script can add rewrite rules, that rename section names
that are automatically used as index entries.  For example we might
want to remove leading "A" or "The" prefixes from section titles
when AutoIndex uses them as an index entry:

   !rewrite-name "(?i)(?:A|The)\s+(.*)" "\1"
   
[h4 Step 5: Iterate]

Creating a good index is an iterative process, often the first step is
just to add a header scanning rule to the script file and then generate
the documentation and see:

* What's missing.
* What's been included that shouldn't be.
* What's been included under a poor name.

Further rules can then be added to the script to handle these cases
and the next iteration examined, and so on.

[endsect]

[section:script_ref Script File Reference]

The following elements can occur in a script:

[h4 Simple Inclusions]

   term [regular-expression1 [regular-expression2 [category]]]
   
[variablelist
[[term][The term to index: this will form a primary entry in the Index
with the section title(s) containing the term as secondary entries, and
also will be used as a secondary entry beneath each of the section
titles that the term occurs in.]]

[[regular-expression1][An optional regular expression: each occurance
of the regular expression in the text of the document will result
in one index term being emitted.

If the regular expression is omitted or is "", then the ['term] itself
will be used as the search text - and only occurance of whole words matching
['term] will be indexed.]]

[[regular-expression2][A constraint that specifies which sections are
indexed for ['term]: only if the ID of the section matches
['regular-expression2] exactly will that section be indexed for occurances
of ['term].

For example:

   `myclass "" "mylib.examples.*"`
   
Will index occurances of "myclass" as a whole word only in sections
whose ID begins "mylib.examples", while:

   `myclass "" "(?!mylib.introduction.*).*"`
   
will index occurances of "myclass" in any section, except those whose
ID's begin "mylib.introduction".]]

[[category][Optionally an index category to place occurances of
['term] in.  If you have multiple indexes then this is the name
assigned to the indexes "type" attribute.
]]

]

[h4 Source File Scanning]

   !scan source-file-name
   
Scans the C\/C++ source file ['source-file-name] for definitions of
['function]'s, ['class]'s, ['macro]'s or ['typedef]'s and makes each of
these a term to be indexed.  Terms found are assigned to the index category
"function_name", "class_name", "macro_name" or "typedef_name" depending
on how they were seen in the source file.  These may then be included
in a specialised index whose "type" attribute has the same category name.

[h4 Directory and Source File Scanning]

   !scan-path directory-name file-name-regex [recurse]
   
[variablelist
[[directory-name][The directory to scan: this should be a path relative
to the script file and should use all forward slashes in it's file name.]]

[[file-name-regex][A regular expression: any file in the directory whose name
matches the regular expression will be scanned for terms to index.]]

[[recurse][An optional boolian value - either "true" or "false" - that
indicates whether to recurse into subdirectories.]]
]

[h4 Excluding Terms]

   !exclude term-list
   
Excludes all the terms in whitespace separated ['term-list] from being indexed.
This should be placed /after/ any ['!scan] or ['!scan-path] rules which may
result in the terms becoming included.

[h4 Rewriting Section Names]

   !rewrite-id regular-expression new-name
   
[variablelist
[[regular-expression][A regular expression: all section ID's that match
the expression exactly will have index entries ['new-name] instead of 
their title(s).]]

[[new-name][The name that the section will appear under in the index.]]
]

   !rewrite-name regular-expression format-text
   
[variablelist
[[regular-expression][A regular expression: all sections whose titles
match the regular expression exactly, will have index entries composed
of the regular expression match combined with the regex format string
['format-text].]]
[[format-text][The Perl-style format string used to reformat the title.]]
]

[endsect]

[section:comm_ref Command Line Reference]

The following command line options are supported by auto_index:

[variablelist
[[in=infilename][Specifies the name of the XML input file to be indexed.]]
[[out=outfilename][Specifies the name of the new XML file to create.]]
[[scan=source-filename][Specifies that ['source-filename] should be scanned
for terms to index.]]
[[script=script-filename][Specifies the name of the script file to process.]]
[[--no-duplicates][If a term occurs more than once in the same section, then
include only one index entry.]]
[[--internal-index][Specifies that auto_index should generate the actual
indexes rather than inserting `<indexterm>`'s and leaving index generation
to the XSL stylesheets.]]
]

[endsect]