[article Boost.AutoIndex
    [quickbook 1.5]
    [copyright 2008, 2011 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) $]
]

[def __quickbook  [@http://www.boost.org/doc/tools/quickbook/index.html Quickbook]]
[def __boostbook [@http://www.boost.org/doc/html/boostbook.html BoostBook]]
[def __boostbook_docs [@http://www.boost.org/doc/libs/1_41_0/doc/html/boostbook.html BoostBook documentation]]
[def __quickbook_syntax [@http://www.boost.org/doc/libs/1_41_0/doc/html/quickbook/ref.html Quickbook Syntax Compendium]]
[def __docbook [@http://www.docbook.org/ DocBook]]
[def __docbook_params [@http://docbook.sourceforge.net/release/xsl/current/doc/ Docbook xsl:param format options]]
[def __DocObjMod [@http://en.wikipedia.org/wiki/Document_Object_Model Document Object Model (DOM)]]

[def __doxygen [@http://www.doxygen.org/ Doxygen]]
[def __pdf [@http://www.adobe.com/products/acrobat/adobepdf.html PDF]]

[template deg[]'''&#xB0;'''] [/ degree sign ]


[section:overview Overview]

AutoIndex is a tool for taking the grunt work out of indexing a
Boostbook\/Docbook document
(perhaps generated by your Quickbook file mylibrary.qbk,
and perhaps using also Doxygen autodoc)
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 occurrence of each term to be
indexed.  

Instead AutoIndex will automatically 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 Docbook XML document for you.

AutoIndex can also scan using a list of index terms 
specified in a script file, for example index.idx.
These manually provided terms can optionally be regular expressions,
and may allow the user to find references to terms
that may not occur in the C++ header files.  Of course providing a manual 
list of search terms in to index is a tedious task 
(especially handling plurals and variants),
and requires enough knowledge of the library
 to guess what users may be seeking to know,
but at least the real 'grunt work' of
finding the term and listing the page number is automated.

AutoIndex creates index entries as follows:

for each occurrence of each search term, it creates two index entries:

# The search term as the ['primary index key] and
 the ['title of the section it appears in] as a subterm.

# The section title as the main index entry and the search term as the subentry.

Thus the user has two chances to find what they're
looking for, based upon either the section name 
or the ['function], ['class], ['macro] or ['typedef] name. 

[note This behaviour can be changed so that only one index entry is created
 (using the search term as the key and
 not using the section name except as a sub-entry of the search term).]

So for example in Boost.Math the class name `students_t_distribution` has a primary
entry that lists all sections the class name 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 author's
expectations (and thus hopefully the index user's expectations too!).

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 attributes 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 poorer by comparison, 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 
appropriate 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]

Finally, you can choose what kind of XML container wraps an internally generated index - 
this defaults to `<section>...</section>` but you can use either command line options 
or Boost.Build Jamfile features, to select an alternative wrapper - for example ['appendix]
or ['chapter] would be good choices, whatever fits best into the flow of the
document.  You can even set the container wrapper to type ['index] provided you turn
off index generation by the XSL stylesheets, for example by setting the following
build requirements in the Jamfile:

[pre
<format>html:<auto-index-internal>on       # Use internally generated indexes.
<auto-index-type>index                     # Use <index>...</index> as the XML wrapper.
<format>html:<xsl:param>generate.index=0   # Don't let the XSL stylesheets generate indexes.
]

[endsect] [/section:overview Overview]

[section:tut Getting Started and Tutorial]

[section:build Step 1: Build the AutoIndex tool]

[note This step is strictly optional, but very desirable to speed up build times.]

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

This will build the tool and place a copy in the current directory (which is to say `tools/auto_index/build`)
   
Now open up your `user-config.jam` file and at the end of the file add the line:

[pre 
using auto-index : ['full-path-to-boost-tree]/tools/auto_index/build/auto-index.exe ; 
]

[note 
This declaration must go towards the end of `user-config.jam`, or in any case after the Boostbook initialisation.

Also note that Windows users must use forward slashes in the paths in `user-config.jam`]

[endsect] [/section:build Step 1: Build the AutoIndex tool]

[section:configure Step 2: Configure Boost.Build jamfile to use AutoIndex]

Assuming you have a Jamfile for building your documentation that looks
something like:

[pre 
boostbook standalone
    :
        mylibrary
    :
        # build requirements go here:
    ;
]

Then add the line:

[pre using auto-index ; ]
   
to the start of the Jamfile, and then add whatever auto-index options
you want to the ['build requirements section], for example:

[pre
   boostbook standalone
    :
        mylibrary
    :
        # Build requirements go here:
        
        # <auto-index>on (or off) one turns on (or off) indexing:
        <auto-index>on
        
        # Turns on (or off) auto-index-verbose for diagnostic info.
        # This is highly recommended until you have got all the many details correct!
        <auto-index-verbose>on 
        
        # Choose the indexing method (separately for html and PDF) - see manual.
        # Choose indexing method for PDFs:
        <format>pdf:<auto-index-internal>off
        
        # Choose indexing method for html:
        <format>html:<auto-index-internal>on
        
        # Set the name of the script file to use (index.idx is popular):
        <auto-index-script>index.idx
        # Commands in the script file should all use RELATIVE PATHS
        # otherwise the script will not be portable to other machines.
        # Relative paths are normally taken as relative to the location 
        # of the script file, but we can add a prefix to all
        # those relative paths using the <auto-index-prefix> feature.
        # The path specified by <auto-index-prefix> may be either relative or
        # absolute, for example the following will get us up to the boost root
        # directory for most Boost libraries:
        <auto-index-prefix>..\/..\/..

        # Tell Quickbook that it should enable indexing.
        <quickbook-define>enable_index ;
      
    ;
] [/pre]

[section:options Available Indexing Options]

The available options are:

[variablelist
[[<auto-index>off/on][Turns indexing of the document on, defaults to
"off", so be sure to set this if you want AutoIndex invoked!]]
[[<auto-index-internal>off/on][Chooses whether AutoIndex creates the index
itself (feature on), or whether it simply inserts the necessary DocBook
markup so that the DocBook XSL stylesheets can create the index.  Defaults to "off".]]
[[<auto-index-script>filename][Specifies the name of the script to load.]]
[[<auto-index-no-duplicates>off/on][When ['on] AutoIndex will only index a term
once in any given section, otherwise (the default) multiple index entries per
term may be created if the term occurs more than once in the section.]]
[[<auto-index-section-names>off/on][When ['on] AutoIndex will use create two
index entries for each term found - one uses the term itself as the primary
index key, the other uses the enclosing section name.  When off the index
entry that uses the section title is not created.  Defaults to "on"]]
[[<auto-index-verbose>off/on][Defaults to "off".  When turned on AutoIndex
prints progress information - useful for debugging purposes during setup.]]
[[<auto-index-prefix>filename][Optionally specifies a directory to apply
as a prefix to all relative file paths in the script file.

You may wish to do this to reduce typing of pathnames, and\/or where the
paths can't be located relative to the script file location,
typically if the headers are in the Boost trunk,
but the script file is in Boost sandbox.

For Boost standard library layout,
[^<auto-index-prefix>..\/..\/..] will get you back up to the 'root' of the Boost tree,
so [^!scan-path boost\/mylibrary\/] is where your headers will be, and [^libs\/mylibrary] for other files.
Without a prefix all relative paths are relative to the location of the script file.
]]

[[<auto-index-type>element-name][Specifies the name of the XML element in which to enclose an internally generated indexes: 
  defaults to ['section], but could equally be ['appendix] or ['chapter] or some other block level element that has a formal title.
   The actual list of available options depends upon the Quickbook document type, the following table gives the available options,
   assuming that the index is placed at the top level, and not in some sub-section or other container:]]
]

[table
[[Document Type][Permitted Index Types]]
[[book][appendix index article chapter reference part]]
[[article][section appendix index sect1]]
[[chapter][section index sect1]]
[[library][The same as Chapter (section index sect1)]]
[[part][appendix index article chapter reference]]
[[appendix][section index sect1]]
[[preface][section index sect1]]
[[qandadiv][N/A: an index would have to be placed within a subsection of the document.]]
[[qandaset][N/A: an index would have to be placed within a subsection of the document.]]
[[reference][N/A: an index would have to be placed within a subsection of the document.]]
[[set][N/A: an index would have to be placed within a subsection of the document.]]
]

In large part then the choice of `<auto-index-type>element-name` depends on the 
formatting you want to be applied to the index:

[table
[[XML Container Used for the Index][Formatting Applied by the XSL Stylesheets]]
[[appendix][Starts a new page.]]
[[article][Starts a new page.]]
[[chapter][Starts a new page.]]
[[index][Starts a new page only if it's contained within an article or book.]]
[[part][Starts a new page.]]
[[reference][Starts a new page.]]
[[sect1][Starts a new page as long as it's not the first section (but is controlled by the XSL parameters chunk.section.depth and/or chunk.first.sections).]]
[[section][Starts a new page as long as it's not the first section or nested within another section (but is controlled by the XSL parameters chunk.section.depth and/or chunk.first.sections).]]
]

In almost all cases the default (section) is the correct choice - the exception is when the index is to be placed
directly inside a /book/ or /part/, in which case you should probably use the same XML container for the index as 
you use for whatever subdivisions are in the /book/ or /part/.  In any event placing a /section/ within a /book/ or 
/part/ will result in invalid XML.

Finally, if you are using Quickbook to generate the documentation, then you may wish to add:

[pre <include>$boost-root/tools/auto_index/include]

to your projects requirements (replacing $boost-root with the path to the root of the Boost tree), so that
the file auto_index_helpers.qbk can be included in your quickbook source with simply a:

[pre \[include auto_index_helpers.qbk\]]

[endsect] [/section:options Available Indexing Options]

[section:optional Making AutoIndex optional]

It is considerate to make the [*use of auto-index optional] in Boost.Build,
to allow users who do not have AutoIndex installed to still be able to build your documentation.

This also very convenient while you are refining your documentation,
to allow you to decide to build indexes, or not:
building indexes can take long time, if you are just correcting typos,
you won't want to wait while you keep rebuilding the index!

One method of setting up optional AutoIndex support is to place all 
AutoIndex configuration in a the body of a bjam if statement:

[pre
  if --enable-index in  \[ modules.peek : ARGV \]
  {
     ECHO "Building the  docs with automatic index generation enabled." ;

     using auto-index ;
     project : requirements
          <auto-index>on
          <auto-index-script>index.idx
          
           ... other AutoIndex options here...

        # And tell Quickbook that it should enable indexing.
        <quickbook-define>enable_index
    ;
  }
  else
  {
     ECHO "Building the my_library docs with automatic index generation disabled. To get an Index, try building with --enable-index." ;
  }
] [/pre]

You will also need to add a conditional statement at the end of your Quickbook file,
so that the index(es) is/are only added after the last section if indexing is enabled.

[pre
\[\? '''enable_index'''
\'\'\'
  <index/>
\'\'\'
\]
] [/pre]


To use this jamfile, you need to cd to your docs folder, for example:

 cd \boost-sandbox\guild\mylibrary\libs\mylibrary\doc
  
and then run `bjam` to build the docs without index, for example: 
  
  bjam -a html > mylibrary_html.log
  
or with index(es)  
  
  bjam -a html --enable-index > mylibrary_html_index.log

[endsect] [/section:optional Making AutoIndex optional]
  
[tip Always send the output to a log file.
It will contain of lot of stuff, but is invaluable to check if all has gone right,
or else diagnose what has gone wrong.
]  [/tip]

[tip A return code of 0 is not a reliable indication
that you have got what you really want - 
inspecting the log file is the only certain way.
] [/tip]

[tip If you upgrade compiler version, for example MSVC from 9 to 10,
then you may need to rebuild Autoindex
to avoid what Microsoft call a 'side-by-side' error.
And make sure that the autoindex.exe version you are using is the new one.
] [/tip]

[endsect] [/section:configure Step 2: Configure Boost.Build to use AutoIndex]

[section:add_indexes Step 3: Add indexes to your documentation]

To add a single "include everything"  index to a BoostBook\/Docbook document,
(perhaps generated using Quickbook, and perhaps also using Doxygen reference section),
add `<index/>` at the location where you want the index to appear.
The index will be rendered as a separate section called "Index"
when the documentation is built.

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

[pre
<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\/>
]

[note Multiple indexes like this only work correctly if you tell the XSL stylesheets
to honor the "type" attribute on each index as by default [/[*they do not do this]].
You can turn the feature on by adding `<xsl:param>index.on.type=1` to your projects
requirements in the Jamfile.]
  
In Quickbook, you add the same markup but enclose it between two triple-tick \'\'\' escapes,
thus

[pre   \'\'\'<index\/>\'\'\' ]

Or more easily via the helper file auto_index_helpers.qbk, so that given:

[pre \[include auto_index_helpers.qbk\]]

one can simply write:

[pre
\[named_index class_name Class Index\]
\[named_index function_name Function Index\]
\[named_index typedef_name Typedef Index\]
\[named_index macro_name Macro Index\]
\[index\]
]
   
[note AutoIndex knows nothing of the XML `xinclude` element, so if
you're writing raw Docbook XML then you may want to run this through an
XSL processor to flatten everything to one XML file before passing to
AutoIndex.  If you're using Boostbook or quickbook though, this all
happens for you anyway, and AutoIndex will index the whole document
including any sections included with `xinclude`.]
   
If you are using AutoIndex's internal index generation on

[pre
<auto-index-internal>on
]
(usually recommended for HTML output, but ['not] the default)
then you can also decide what kind of XML wrapper the generated index is placed in.
By default this is a `<section>...</section>` XML block (this replaces the original
`<index>...</index>` block).  However, depending upon the structure of the document
and whether or not you want the index on a separate page - or else on the front page after
the TOC - you may want to place the index inside a different type of XML block.  For example
if your document uses `<chapter>` top level content rather than `<section>`s then
it may be preferable to place the index in a `<chapter>` or `<appendix>` block.
You can also place the index inside an `<index>` block if you prefer, in which case the index
does not appear in on a page of its own, but after the TOC in the HTML output.

You control the type of XML block used by setting the =<auto-index-type>element-name= 
attribute in the Jamfile, or via the `index-type=element-name` command line option to
AutoIndex itself.  For example, to place the index in an appendix, your Jamfile might 
look like:

[pre
using quickbook ;
using auto-index ;

xml mylibrary : mylibary.qbk ;
boostbook standalone
    :
        mylibrary
    :
        # auto-indexing is on:
        <auto-index>on  
        
        # PDFs rely on the XSL stylesheets to generate the index:
        <format>pdf:<auto-index-internal>off  
        
        # HTML output uses auto-index to generate the index:
        <format>html:<auto-index-internal>on
        
        # Name of script file to use:
        <auto-index-script>index.idx
        
        # Set the XML wrapper for HML Indexes to "appendix":
        <format>html:<auto-index-type>appendix
        
        # Turn on multiple index support:
        <xsl:param>index.on.type=1
]
   

[endsect] [/section:add_indexes Step 3: Add indexes to your documentation]

[section:script Step 4: Create the .idx script file - to control what to terms to index]

AutoIndex works by reading a script file that tells it what terms to index.

If your document contains largely text, and only a small amount of simple C++,
and/or if you are using Doxygen to provide a C++ Reference section 
(that lists the C++ elements),
and/or if you are relying on the indexing provided from a Standalone Doxygen Index,
you may decide that a index is not needed 
and that you may only want the text part indexed.

But if you want C++ classes functions, typedefs and/or macros AutoIndexed,
optionally, the script file also tells which other C++ files to scan.

At its 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
   !scan mydetailsheader.hpp
   
Or, more likely in practice, so
we can recursively scan through directories looking for all
the files to scan whose [*name matches a particular regular expression]:

[pre !scan-path "boost\/mylibrary" ".*\.hpp" true ]
   
Each argument is whitespace separated and can be optionally
enclosed in "double quotes" (recommended).

The final ['true] argument indicates
that subdirectories in `/boost/math/mylibrary` should be searched
recursively in addition to that directory.

[caution The second ['file-name-regex] argument is a regular expression and not a filename GLOB!]

[caution The scan-path is modified by any setting of <auto-index-prefix>.
The examples here assume that this is [^<auto-index-prefix>..\/..\/..]
so that `boost/mylibrary` will be your header files,
`libs/mylibrary/doc` will contain your documentation files and
`libs/mylibrary/example` will contain your examples.
]

You could also scan any examples (.cpp) files,
typically in folder `/mylibrary/lib/example`.

[pre
# All example source files, assuming no sub-folders.
!scan-path "libs\/mylibrary\/example" ".*\.cpp" 
] [/pre]

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 occurrences 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 occurrences of "reflex" as a whole word, but:

   reflex \<reflex\w*\>
   
will index occurrences of "reflex", "reflexing" and 
"reflexed" all under the same entry ['reflex].
You will very often need to use this to deal with plurals and other variants.

This inclusion rule can also restrict 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"
   
[endsect] [/section:script Step 4: Create the script file -  to control what to terms to index]

[section:entries Step 5: Add Manual Index Entries to Docbook XML - Optional]

If you add manual `<indexentry>` markup to your Docbook XML then these will be 
passed through unchanged.  Please note however, that if you are using 
AutoIndex's internal index generation then it only recognises
`<primary>`, `<secondary>` and `<tertiary>` elements within the `<indexterm>`.
`<see>` and `<seealso>` elements are not currently recognised
and AutoIndex will emit a warning if these are used.

Likewise none of the  attributes which can be applied to these elements are used when
AutoIndex generates the index itself, with the exception of the `<type>` attribute.

For Quickbook users, there are some templates in auto_index_helpers.qbk that assist
in adding manual entries without having to escape to Docbook.

[endsect]  [/section:entries Step 5: Add Manual Index Entries to Docbook XML - Optional]

[section:pis Step 6: Using XML processing instructions to control what gets indexed.]

Sometimes when you need to exclude certain sections of text from indexing, 
then you can achieve this with the following XML processing instructions:

[table
[[Instruction][Effect]]
[[`<?BoostAutoIndex IgnoreSection?>`]
   [Causes the whole of the current section to be excluded from indexing.
    By "section" we mean either a true "section" or any sibling XML element:
    "dedication", "toc", "lot", "glossary", "bibliography", "preface", "chapter", 
      "reference", "part", "article", "appendix", "index", "setindex", "colophon",
      "sect1", "refentry", "simplesect", "section" or "partintro".]]
[[`<?BoostAutoIndex IgnoreBlock?>`]
   [Causes the whole of the current text block to be excluded from indexing.
    A text block may be any of the section/chapter elements listed above, or a 
    paragraph, code listing, table etc.  The complete list is:
    "calloutlist", "glosslist", "bibliolist", "itemizedlist", "orderedlist", 
      "segmentedlist", "simplelist", "variablelist", "caution", "important", "note", 
      "tip", "warning", "literallayout", "programlisting", "programlistingco", 
      "screen", "screenco", "screenshot", "synopsis", "cmdsynopsis", "funcsynopsis", 
      "classsynopsis", "fieldsynopsis", "constructorsynopsis", 
      "destructorsynopsis", "methodsynopsis", "formalpara", "para", "simpara", 
      "address", "blockquote", "graphic", "graphicco", "mediaobject", 
      "mediaobjectco", "informalequation", "informalexample", "informalfigure", 
      "informaltable", "equation", "example", "figure", "table", "msgset", "procedure", 
      "sidebar", "qandaset", "task", "productionset", "constraintdef", "anchor", 
      "bridgehead", "remark", "highlights", "abstract", "authorblurb" or "epigraph".]]
]

For Quickbook users the file auto_index_helpers.qbk contains a helper template
that assists in inserting these processing instructions, for example:

[pre \[AutoIndex IgnoreSection\]]

Will cause that section to not be indexed.

[endsect] [/section:pis Step 6: Using XML processing instructions to control what gets indexed.]

[section:build_docs Step 7: Build the Docs]

Using Boost.Build you build the docs with either:

   bjam release > mylibrary_html.log

To build the html docs or:

   bjam pdf release > mylibrary_pdf.log

To build the pdf.

During the build process you should see AutoIndex emit a message in the log file
such as:

[pre Indexing 990 terms... ]
   
If you don't see that, or if it's indexing 0 terms then something is wrong!

Likewise when index generation is complete, AutoIndex will emit another message:

[pre 38 Index entries were created.]

Again, if you see that 0 entries were created then something is wrong!

Examine the log file, and if the cause is not obvious, 
make sure that you have [^<auto-index-verbose>on] and that
any needed
[^!debug regular-expression] directives are in your script file. 

[endsect] [/section:build_docs Step 7: Build the Docs]

[section:refine Step 8: Iterate - to refine your index]

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.

[tip If you don't understand why a particular term is (or is not) present in the index,
try adding a ['!debug regular-expression] 
directive to the [link boost_autoindex.script_ref script file].
] [/tip]

[heading Restricting which Sections are indexed for a particular term]

You can restrict which sections are indexed for a particular term.
So assuming that the docbook document has the usual hierarchical names for section ID's
(as Quickbook generates, for example),
you can easily place a constraint on which sections are examined for a particular term.

For example, if you want to index occurrences of Lord Kelvin's name,
but only in the introduction section, you might then add:

  Kelvin "" ".*introduction.*"

to the script file,
assuming that the section ID of the intro is "some_library_or_chapter_name.introduction".

This would avoid an index entry every time 'Kelvin' is found,
something the user is unlikely to find helpful.

[endsect] [/section:refine Step 8: Iterate - to refine your index]

[endsect] [/section:tut Getting Started and Tutorial]


[section:script_ref Script File (.idx) Reference]

The following elements can occur in a script:

[h4 Comments and blank lines]

Blank lines consisting of only whitespace are ignored, so are lines that [*start with a #].

[note You can't append \# comments onto the end of a line\!]

[h4 Inclusion of Index terms]

   term [regular-expression1 [regular-expression2 [category]]]
   
[variablelist
[[term][
['Term to index.]

The index term 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 index term occurs in.]
] [/term]

[[regular-expression1][
['Index term Searcher.]

An optional regular expression: each occurrence
of the regular expression in the text of the document will result
in one index term being emitted.

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

For example:

``foobar``

will index occurrences of "foobar" in any section, but

``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.

``reflex``

will only index occurrences of "reflex" as a whole word, but: 

``reflex \<reflex\w*\>``

will index occurrences of "reflex", "reflexes", "reflexing" and "reflexed" ...
all under the same entry reflex.

You will very often need to use this to deal with plurals and other variants.]
] [/regular-expression1]

[[regular-expression2]
[['Section(s) Selector.]

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 occurrences of ['term].

For example, to limit indexing to just [*one specific section] (but not sub-sections below):

``myclass "" "mylib\.examples"``


For example, to limit indexing to specific sections, [*and sub-sections below]:

``myclass "" "mylib\.examples.*"``
   
will index occurrences of "myclass" as a whole word,
but only in sections whose section ID [*begins] "mylib.examples", while

``myclass "\<myclass\w*\>" "mylib\.examples.*"``

will also index plurals myclass, myclasses, myclasss ...

and:

``myclass "" "(?!mylib\.introduction).*"``
   
will index occurrences of "myclass" in any section,
except those whose section IDs begin "mylib.introduction".

Finally, two (or more) sections can be excluded by OR'ing them together:

``myclass "" "(?!mylib\.introduction|mylib\.reference).*"``

which excludes searching for this term in sections whose ID's start with either "mylib.introduction" or "mylib.reference".
   
If this third section selection field is omitted (the default)
or is "", then [*all sections] are indexed for this term.
]
] [/regular-expression2]

[[category][
['Index Category Constraint.]

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

For example:
  
  myclass "" "" class_name

Will index occurances of ['myclass] and place them in the class-index if there is one.

]] [/category]

]  [/variablelist]

You can have an index term appear more than once in the script file:

* If they have different /category/ names then they are treated quite separately.
* Otherwise they are combined, so that the logical or of the regular expressions provided are taken.

Thus:

   myterm search_expression1 constrait_expression2 foo
   myterm search_expression1 constrait_expression2 bar

Will be treated as different terms each with their own entries, while:

   myterm search_expression1 constrait_expression2 mycategory
   myterm search_expression1 constrait_expression2 mycategory

Will be combined into a single term equivalent to:

   myterm (?:search_expression1|search_expression1) (?:constrait_expression2|constrait_expression2) mycategory

[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.

[important
When actually indexing a document, the scanner will not index just any old occurrence of the
terms found in the source files.  Instead it searches for class definitions or function or
typedef declarations.  This reduces the number of spurious matches placed in the index, but 
may also miss some legitimate terms:
refer to the /define-scanner/ command for information on how to change this.
]

[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 (or to the path specified with the prefix=path option on the command line) 
and should use all forward slashes in its 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 boolean value - either "true" or "false" - that
indicates whether to recurse into subdirectories.  This defaults to "false".]]
]

[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.  In other words this removes terms from
the scanners internal list of things to index.

[h4 Rewriting Section Names]

[pre !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.]]
]

For example:

[pre
!rewrite-name "(?:A|An|The)\s+(.*)" "\1"
]

Will remove any leading "A", "An" or "The" from all index entries - thus preventing lots of
entries under "The" etc!

[h4 Defining or Changing the File Scanners]

   !define-scanner type file-search-expression xml-regex-formatter term-formatter id-filter filename-filter

When a source file is scanned using the =!scan= or =!scan-path= rules, then the file is searched using
a series of regular expressions to look for classes, functions, macros or typedefs that should be indexed.
A set of default regular expressions are provided for this (see below), but sometimes you may want to replace 
the defaults, or add new scanners.  The arguments to this rule are:

[variablelist
[[type][The ['type] to which items found using this rule will assigned, index terms created from the 
source file and then found in the XML, will have the type attribute set to this value, and may then appear in a 
specialized index with the same type attribute]]
[[file-search-expression][A regular expression that is used to scan the source file for index terms, the result of
a match against this expression will be transformed by the next two arguments.]]
[[xml-regex-formatter][A regular expression format string that extracts the salient information from whatever
matched the ['file-search-expression] in the source file, and creates ['a new regular expression] that will
be used to search the document being indexed for occurrences of this index term.]]
[[term-formatter][A regular expression format string that extracts the salient information from whatever
matched the ['file-search-expression] in the source file, and creates the index term that will appear in
the index.]]
[[id-filter][Optional.  A regular expression that restricts the section-id's that are searched in the document being indexed: 
only sections whose ID attribute matches this expression exactly will be considered for indexing terms found by this scanner.]]
[[filename-filter][Optional.  A regular expression that restricts which files are scanned by this scanner: only files whose file name
matches this expression exactly will be scanned for index terms to use.  Note that the filename matched against this may
well be an absolute path, and contain either forward or backward slash path separators.]]
]

If, when the first file is scanned, there are no scanners whose ['type] is "class_name", "typedef_name", "macro_name" or 
"function_name", then the defaults are installed.  These are equivalent to:

   !define-scanner class_name "^[[:space:]]*(template[[:space:]]*<[^;:{]+>[[:space:]]*)?(class|struct)[[:space:]]*(\<\w+\>([[:blank:]]*\([^)]*\))?[[:space:]]*)*(\<\w*\>)[[:space:]]*(<[^;:{]+>)?[[:space:]]*(\{|:[^;\{()]*\{)" "(?:class|struct)[^;{]+\<\5\>[^;{]+\{" \5
   !define-scanner typedef_name "typedef[^;{}#]+?(\w+)\s*;"  "typedef[^;]+\<\1\>\s*;" "\1"
   !define-scanner "macro_name" "^\s*#\s*define\s+(\w+)" "\<\1\>" "\1"
   !define-scanner "function_name" "\w++(?:\s*+<[^>]++>)?[\s&*]+?(\w+)\s*(?:BOOST_[[:upper:]_]+\s*)?\([^;{}]*\)\s*[;{]" "\\<\\w+\\>(?:\\s+<[^>]*>)*[\\s&*]+\\<\1\\>\\s*\\([^;{]*\\)" "\1"

Note that these defaults are not installed if you have provided your own versions with these ['type] names. In this case if
you want the default scanners to be in effect as well as your own, you should include the above in your script file.  
It is also perfectly allowable to have multiple scanners with the same ['type], but with the other fields differing.

Finally you should note that the default scanners are quite strict
in what they will find, for example the class
scanner will only create index entries for classes that have class definitions of the form:

   class my_class : public base_classes
   {
      // etc

In the documentation, so that simple mentions of the class name will ['not] get indexed,
only the class synopsis if there is one.
If this isn't how you want things, then include the ['class_name] scanner definition
above in your script file, and change
the ['xml-regex-formatter] field to something more permissive, for example: 

   !define-scanner class_name "^[[:space:]]*(template[[:space:]]*<[^;:{]+>[[:space:]]*)?(class|struct)[[:space:]]*(\<\w+\>([[:blank:]]*\([^)]*\))?[[:space:]]*)*(\<\w*\>)[[:space:]]*(<[^;:{]+>)?[[:space:]]*(\{|:[^;\{()]*\{)" "\<\5\>" \5

Will look for ['any] occurrence of whatever class names the scanner may find in the documentation.

[h4 Debugging scanning]

If you see a term in the index, and you don't understand why it's there, add a ['debug] directive:

[pre
!debug regular-expression
]

Now, whenever ['regular-expression] matches either the found index term,
or the section title it appears in, or the ['type] field of a scanner, then
some diagnostic information will be printed that will look something like:

[pre
Debug term found, in block with ID: spirit.qi.reference.parser_concepts.parser
Current section title is: Notation
The main index entry will be : Notation
The indexed term is: parser
The search regex is: \[P\|p\]arser
The section constraint is: .*qi.reference.parser_concepts.*
The index type for this entry is: qi_index
]

This can produce a lot of output in your log file,
but until you are satisfied with your file selection and scanning process,
it is worth switching it on.

[endsect] [/section:script_ref Script File Reference]

[section:workflow  Understanding The AutoIndex Workflow]

# Load the script file (usually index.idx) 
  and process it one line at a time,
  producing one or more index term per (non-comment) line.

# Reading all lines builds a list of ['terms to index].
  Some of those may be terms defined (by you) directly in the script file,
  others may be terms found by scanning C++ header and source files
  that were specified by the ['!scan-path] directive.

# Once the complete list of ['terms to index] is complete,
  it loads the Docbook XML file.
  (If this comes from Quickbook\/Doxygen\/Boostbook\/Docbook then this is
  the complete documentation after conversion to Docbook format).

# AutoIndex builds an internal __DocObjMod of the Docbook XML.
  This internal representation then gets scanned for occurrences of the ['terms to index].
  This scanning works at the XML paragraph level
  (or equivalent sibling such as a table or code block)
  - so all the XML encoding within a paragraph gets flattened to plain text.[br]
  This flattening means the regular expressions used to search for ['terms to index]
  can find anything that is completely contained within a paragraph 
  (or code block etc).

# For each term found then an ['indexterm] Docbook element is inserted
  into the __DocObjMod (provided internal index generation is off),

# Also the AutoIndex's internal index representation gets updated.

# Once the whole XML document has been indexed, 
  then, if AutoIndex has been instructed to generate the index itself,
  it creates the necessary XML and inserts this into the __DocObjMod.

# Finally the whole __DocObjMod is written out as a new Docbook XML file,
  and normal processing of this continues via the XSL stylesheets (with xsltproc)
  to actually build the final human-readable docs.

[endsect] [/section:workflow  AutoIndex Workflow]


[section:xml XML Handling]

AutoIndex is rather simplistic in its handling of XML:

* When indexing a document, all block content at the paragraph level gets collapsed into a single
string for matching against the regular expressions representing each index term.  In other words,
for the most part, you can assume that you're indexing plain text when writing regular expressions.
* Named XML entities for &, ", ', < or > are converted to their corresponding characters before indexing 
a section of text.  However, decimal or hex escape sequences are not currently converted.
* Index terms are assumed to be plain text (whether they originate from the script file
or from scanning source files) and the characters &, ", < and > will be escaped to
&amp; &quot; &lt; and &gt; respectively.

[endsect] [/section:xml XML Handling]

[section:qbk Quickbook Support]

The file auto_index_helpers.qbk in ['boost-path]/tools/auto_index/include contains various Quickbook
templates to assist with AutoIndex support.  One would normally add the above path to your include
search path via an `<include>path` statement in your Jamfile, and then make the templates available
to your Quickbook source via a:

[pre \[include auto_index_helpers.qbk\]]

statement at the start of your Quickbook file.

The available templates are then:

[table
[[Template][Description]]
[[`[index]`][Creates a main index, with no "type" category set, which will be titled simply "Index".]]
[[`[named_index type title]`][Creates an index with the type attribute set to "type" and the title will be "title".[br]
         For example to create an index containing only class names one would typically add `[named_index class_name Class Index]`
         to your Quickbook source.]]
[[`[AutoIndex Arg]`][Creates a Docbook processing instruction that will be handled by AutoIndex, valid values for "Arg" 
                     are either "IgnoreSection" or "IgnoreBlock".]]
[[`[indexterm1 primary-key]`][Creates a manual index entry that will link to the current section, and have a single primary key "primary-key".
         Note that this index key will not have a "type" attribute set, and so will only appear in the main index.]]
[[`[indexterm2 primary-key secondary-key]`][Creates a manual index entry that will link to the current section, and has 
         "primary-key" and "secondary key" as the primary and secondary keys respectively.
         Note that this index key will not have a "type" attribute set, and so will only appear in the main index.]]
[[`[indexterm3 primary-key secondary-key tertiary-key]`][Creates a manual index entry that will link to the current section, 
         and have primary, secondary and tertiary keys: "primary-key", "secondary key" and "tertiary key".
         Note that this index key will not have a "type" attribute set, and so will only appear in the main index.]]

[[`[typed_indexterm1 type primary-key]`][Creates a manual index entry that will link to the current section, and have a single primary key "primary-key".
         Note that this index key will have the  "type" attribute set to the "type" argument, and so may appear in named sub-indexes
         that also have their type attribute set.]]
[[`[typed_indexterm2 type primary-key secondary-key]`][Creates a manual index entry that will link to the current section, and has 
         "primary-key" and "secondary key" as the primary and secondary keys respectively.
         Note that this index key will have the  "type" attribute set to the "type" argument, and so may appear in named sub-indexes
         that also have their type attribute set.]]
[[`[typed_indexterm3 type primary-key secondary-key tertiary-key]`][Creates a manual index entry that will link to the current section, 
         and have primary, secondary and tertiary keys: "primary-key", "secondary key" and "tertiary key".
         Note that this index key will have the  "type" attribute set to the "type" argument, and so may appear in named sub-indexes
         that also have their type attribute set.]]
]

[endsect]

[section:comm_ref Command Line Reference]

The following command line options are supported by AutoIndex:

[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 AutoIndex should generate the actual
indexes rather than inserting `<indexterm>`s and leaving index generation
to the XSL stylesheets.]]
[[--no-section-names][Prevents AutoIndex from using section names as index entries.]]
[[--prefix=pathname][Specifies a directory to apply as a prefix to all relative file paths in the script file.]]
[[--index-type=element-name][Specifies the name of the XML element to enclose internally generated indexes in: 
  defaults to ['section], but could equally be ['appendix] or ['chapter]
  or some other block level element that has a formal title.]]
]

[endsect]  [/section:comm_ref Command Line Reference]

[include ../include/auto_index_helpers.qbk]

[index]
