@node Texinfo::Structuring
@chapter Texinfo::Structuring

@menu
* Texinfo@asis{::}Structuring NAME::
* Texinfo@asis{::}Structuring SYNOPSIS::
* Texinfo@asis{::}Structuring DESCRIPTION::
* Texinfo@asis{::}Structuring METHODS::
* Texinfo@asis{::}Structuring SEE ALSO::
* Texinfo@asis{::}Structuring AUTHOR::
* Texinfo@asis{::}Structuring COPYRIGHT AND LICENSE::
@end menu

@node Texinfo::Structuring NAME
@section NAME

Texinfo::Structuring - informations and transformations in Texinfo::Parser tree

@node Texinfo::Structuring SYNOPSIS
@section SYNOPSIS

@verbatim
  use Texinfo::Structuring qw(sectioning_structure nodes_tree number_floats
    associate_internal_references split_by_node split_by_section split_pages
    merge_indices sort_indices_by_letter sort_indices elements_directions
    elements_file_directions);
  # $tree is a Texinfo document tree.  $parser is a Texinfo::Parser object.
  my $sections_root = sectioning_structure ($parser, $tree);
  my $top_node = nodes_tree($parser);
  number_floats($parser->floats_information());
  associate_internal_references($parser);
  my $elements;
  if ($split_at_nodes) {
    $elements = split_by_node($tree);
  } else {
    $elements = split_by_section($tree);
  }
  split_pages($elements, $split);
  elements_directions($parser, $elements);
  elements_file_directions($parser, $elements);

  my ($index_names, $merged_indices) 
     = $parser->indices_information();
  my $merged_index_entries
     = merge_indices($index_names);
  my $index_entries_sorted;
  if ($sort_by_letter) {
    $index_entries_sorted = sort_indices_by_letter($parser,
                                       $merged_index_entries, $index_names);
  } else {
    $index_entries_sorted = sort_indices($parser, $merged_index_entries,
                                         $index_names);
  }
  
  
@end verbatim

@node Texinfo::Structuring DESCRIPTION
@section DESCRIPTION

Texinfo::Structuring first allows to collect informations on a Texinfo tree.
In most case, it also requires a parser object to do that job.  Thanks to
@code{sectioning_structure} the hierarchy of sectioning commands is determined.
The node and menus tree is analysed with @code{nodes_tree}.  Floats get their 
standard numbering with @code{number_floats} and internal references are matched
up with nodes, floats or anchors with @code{associate_internal_references}.

It is also possible to group the top-level contents of the tree, which consist
in nodes and sectioning commands into elements that group together a node and
the next sectioning element.  With @code{split_by_node} nodes are considered
to be the main sectionning elements, while with @code{split_by_section} the 
sectioning command elements are the main elements.  The first mode is typical
of Info format, while the second correspond to a traditional book.
The elements may be further split in @emph{pages}, which are not pages as
in book pages, but more like web pages, and hold series of elements.

The elements may have directions to other elements prepared 
by @code{elements_directions}.  @code{elements_file_directions} should also
set direction related to files, provided files are associated with 
elements by the user.

@code{merge_indices} may be used to merge indices, which may be sorted
with @code{sort_indices} or @code{sort_indices_by_letter} to sort by letters.

Other miscellaneous methods include @code{set_menus_to_simple_menu} and
@code{menu_to_simple_menu} to change the menu texinfo tree, as well
as @code{insert_nodes_for_sectioning_commands} that adds nodes for 
sectioning commands without nodes and @code{complete_tree_nodes_menus}
that completes the node menus based on the sectioning tree.

@node Texinfo::Structuring METHODS
@section METHODS

No method is exported in the default case.

Most of those function references takes a Texinfo::Parser object
as argument, see @ref{Texinfo::Parser NAME}.

@table @asis
@item $sections_root = sectioning_structure ($parser, $tree)
@anchor{Texinfo::Structuring $sections_root = sectioning_structure ($parser@comma{} $tree)}

This function goes through the tree and gather information on
the document structure for sectioning commands.  It returns the 
root of the sectioning commands tree.

For section elements, it sets:

@table @asis
@item level
@anchor{Texinfo::Structuring level}

The level in the sectioning tree hierarchy.  0 is for @code{@@top} or 
@code{@@part}, 1 for @code{@@chapter}, @code{@@appendix}...  This level is corrected
by @code{@@raisesections} and @code{@@lowersections}.

@item number
@anchor{Texinfo::Structuring number}

The sectioning element number.

@item section_childs
@anchor{Texinfo::Structuring section_childs}

An array holding sectioning elements children of the element.

@item section_up
@anchor{Texinfo::Structuring section_up}

@item section_prev
@anchor{Texinfo::Structuring section_prev}

@item section_next
@anchor{Texinfo::Structuring section_next}

The up, previous and next sectioning elements.

@item toplevel_next
@anchor{Texinfo::Structuring toplevel_next}

@item toplevel_prev
@anchor{Texinfo::Structuring toplevel_prev}

@item toplevel_up
@anchor{Texinfo::Structuring toplevel_up}

The next and previous and up sectioning elements of toplevel sectioning
elements (like @code{@@top}, @code{@@chapter}, @code{@@appendix}), not taking into 
account @code{@@part} elements.

@end table

@item my $top_node = nodes_tree($parser)
@anchor{Texinfo::Structuring my $top_node = nodes_tree($parser)}

Goes through menu and nodes and set directions.  Returns the top
node.

This functions sets:

@table @asis
@item menu_child
@anchor{Texinfo::Structuring menu_child}

The first child in the menu of the node.

@item menu_up
@anchor{Texinfo::Structuring menu_up}

@item menu_next
@anchor{Texinfo::Structuring menu_next}

@item menu_prev
@anchor{Texinfo::Structuring menu_prev}

Up, next and previous directions as set in menus.

@item node_up
@anchor{Texinfo::Structuring node_up}

@item node_prev
@anchor{Texinfo::Structuring node_prev}

@item node_next
@anchor{Texinfo::Structuring node_next}

Up, next and previous directions for the node.

@end table

@item number_floats($float_information)
@anchor{Texinfo::Structuring number_floats($float_information)}

Number the floats as described in the Texinfo manual.  Sets
the @emph{number} key of the float tree elements.

@item associate_internal_references($parser)
@anchor{Texinfo::Structuring associate_internal_references($parser)}

Verify that internal references (@code{@@ref} and similar without
fourth of fifth argument) have an associated node, anchor or float.
Set the @emph{label} key in the @emph{extra} hash of the reference tree
element to the associated labeled tree element.

@item $elements = split_by_node($tree)
@anchor{Texinfo::Structuring $elements = split_by_node($tree)}

Returns a reference array of elements where a node is associated to
the following sectioning commands.  Sectioning commands without nodes
are also with the previous node, while nodes without sectioning commands
are alone in their elements.

Elements are regular tree items with type @emph{element}, the
associated nodes and sectioning tree items are in the array associated
with the @emph{contents} key.  They have directions, namely @emph{element_next}
and @emph{element_prev} pointing to the previous and the next element.

In the @emph{extra} hash they have

@table @asis
@item no_node
@anchor{Texinfo::Structuring no_node}

A special case, if there are no nodes in the document, the value is set.

@item node
@anchor{Texinfo::Structuring node}

@item element_command
@anchor{Texinfo::Structuring element_command}

The node command associated with the element.

@item section
@anchor{Texinfo::Structuring section}

The sectioning command associated with the element node.

@end table

@item $elements = split_by_section($tree)
@anchor{Texinfo::Structuring $elements = split_by_section($tree)}

Similarly with @code{split_by_node}, returns an array of elements.  This time,
lone nodes are associated with the previous sections and lone sections
makes up an element.

The extra hash keys set are the same, except that @emph{element_command} is 
the sectioning command associated with the element, and @emph{no_node} is 
replaced by @emph{no_section}.

@item $pages = split_pages($elements, $split)
@anchor{Texinfo::Structuring $pages = split_pages($elements@comma{} $split)}

The elements from the array reference argument have an extra @emph{first_in_page}
value set to the first element on the unit, and based on the
value of @emph{$split}.  The possible values for @emph{$split} are

@table @asis
@item chapter
@anchor{Texinfo::Structuring chapter}

The elements are split at chapter or other toplevel sectioning elements.

@item node
@anchor{Texinfo::Structuring node 1}

Each element has its own page.

@item section
@anchor{Texinfo::Structuring section 1}

The elements are split at sectioning commands below chapter.

@item value evaluating to false
@anchor{Texinfo::Structuring value evaluating to false}

No splitting, only one page is returned, holding all the elements.

@end table

@item elements_directions($parser, $elements)
@anchor{Texinfo::Structuring elements_directions($parser@comma{} $elements)}

Directions are set up for the elements in the array reference given in 
argument.  The corresponding hash reference is in 
@code{@{'extra'@}->@{'directions'@}}
and keys correspond to directions while values are elements.

The following directions are set up:

@table @asis
@item This
@anchor{Texinfo::Structuring This}

The element itself.

@item Forward
@anchor{Texinfo::Structuring Forward}

Element next.

@item Back
@anchor{Texinfo::Structuring Back}

Previous element.

@item NodeForward
@anchor{Texinfo::Structuring NodeForward}

Following node element in reading order.  It is the next node, or the 
first in menu or the next of the up node.

@item NodeBack
@anchor{Texinfo::Structuring NodeBack}

Preceding node element.

@item NodeUp
@anchor{Texinfo::Structuring NodeUp}

@item NodeNext
@anchor{Texinfo::Structuring NodeNext}

@item NodePrev
@anchor{Texinfo::Structuring NodePrev}

The up, next and previous node elements.

@item Up
@anchor{Texinfo::Structuring Up}

@item Next
@anchor{Texinfo::Structuring Next}

@item Prev
@anchor{Texinfo::Structuring Prev}

The up, next and previous section elements.

@item FastForward
@anchor{Texinfo::Structuring FastForward}

The next top level section element.

@item FastBack
@anchor{Texinfo::Structuring FastBack}

For top level elements, the previous top level element.  For other elements
the up top level element.  For example, for a chapter element it is the 
previous chapter, for a subsection element it is the chapter element 
that contains the subsection.

@item FastForward
@anchor{Texinfo::Structuring FastForward 1}

The next top level element.

@end table

@item elements_file_directions($parser, $elements)
@anchor{Texinfo::Structuring elements_file_directions($parser@comma{} $elements)}

In the directions reference described above for @code{elements_directions}, sets
the @emph{PrevFile} and @code{NextFile} directions to the elements in previous and
following files.  

The API for association of pages/elements to files is not defined yet.

@item $merged_entries = merge_indices($index_names)
@anchor{Texinfo::Structuring $merged_entries = merge_indices($index_names)}

Using informations returned by @ref{Texinfo::Parser indices_information},
a structure holding all the index entries by index name is returned, 
with all the entries of merged indices merged with those of the indice 
merged into.

The @emph{$merged_entries} returned is a hash reference whose
keys are the index names and values arrays of index entry structures
described in details in @ref{Texinfo::Parser index_entries}.

@item $index_entries_sorted = sort_indices_by_letter($parser, $merged_index_entries, $index_names)
@anchor{Texinfo::Structuring $index_entries_sorted = sort_indices_by_letter($parser@comma{} $merged_index_entries@comma{} $index_names)}

@item $index_entries_sorted = sort_indices($parser, $merged_index_entries, $index_names)
@anchor{Texinfo::Structuring $index_entries_sorted = sort_indices($parser@comma{} $merged_index_entries@comma{} $index_names)}

These functions first sets a plain text key for each index entry, used for 
sorting.  In both cases, a hash reference with index names as keys is returned.

When sorting by letter, an array reference of letter hash references is 
associated with each index name.  Each letter hash reference has two 
keys, a @emph{letter} key with the letter, and an @emph{entries} key with an array
reference of sorted index entries beginning with the letter.

When simply sorting, the array of the sorted indes entries is associated
with the index name.

@item ($root_content, $added_sections) = fill_gaps_in_sectioning ($root)
@anchor{Texinfo::Structuring ($root_content@comma{} $added_sections) = fill_gaps_in_sectioning ($root)}

This function adds empty @code{@@unnumbered} and similar commands in a tree
to fill gaps in sectioning.  This may be used, for example, when converting 
from a format that can handle gaps in sectioning.  @emph{$root} is the tree
root.  An array reference is returned, containing the root contents
with added sectioning commands, as well as an array reference containing 
the added sectioning commands.

If the sectioning commands are lowered or raised (with @code{@@raisesections},
@code{@@lowersection}) the tree may be modified with @code{@@raisesections} or
@code{@@lowersection} added to some tree elements.

@item menu_to_simple_menu ($menu)
@anchor{Texinfo::Structuring menu_to_simple_menu ($menu)}

@item set_menus_to_simple_menu ($parser)
@anchor{Texinfo::Structuring set_menus_to_simple_menu ($parser)}

@code{menu_to_simple_menu} transforms the tree of a menu tree element.  
@code{set_menus_to_simple_menu} calls @code{menu_to_simple_menu} for all the
menus of the document.

A simple menu has no @emph{menu_comment}, @emph{menu_entry} or @emph{menu_entry_description}
container anymore, their content are merged directly in the menu in 
@emph{preformatted} container.

@item ($root_content, $added_nodes) = insert_nodes_for_sectioning_commands ($parser, $tree)
@anchor{Texinfo::Structuring ($root_content@comma{} $added_nodes) = insert_nodes_for_sectioning_commands ($parser@comma{} $tree)}

Insert nodes for sectioning commands without node in @code{$tree}.
An array reference is returned, containing the root contents
with added nodes, as well as an array reference containing the 
added nodes.

@item complete_tree_nodes_menus ($parser, $tree)
@anchor{Texinfo::Structuring complete_tree_nodes_menus ($parser@comma{} $tree)}

Add menu entries or whole menus for nodes associated with sections,
based on the sectioning tree.  This function should therefore be
called after @ref{,,, sectioning_structure}.

@item $detailmenu = new_master_menu ($parser)
@anchor{Texinfo::Structuring $detailmenu = new_master_menu ($parser)}

Returns a detailmenu tree element formatted as a master node.

@item regenerate_master_menu ($parser)
@anchor{Texinfo::Structuring regenerate_master_menu ($parser)}

Regenerate the Top node master menu, replacing the first detailmenu
in Top node menus or appending at the end of the Top node menu.

@end table

@node Texinfo::Structuring SEE ALSO
@section SEE ALSO

@url{http://www.gnu.org/s/texinfo/manual/texinfo/, Texinfo manual}, 
@ref{Texinfo::Parser NAME}.

@node Texinfo::Structuring AUTHOR
@section AUTHOR

Patrice Dumas, <pertusus@@free.fr>

@node Texinfo::Structuring COPYRIGHT AND LICENSE
@section COPYRIGHT AND LICENSE

Copyright 2010, 2011, 2012 Free Software Foundation, Inc.

This library is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License,
or (at your option) any later version.

