NAME

       PPI::Document - Object representation of a Perl document

INHERITANCE

         PPI::Document
         isa PPI::Node
             isa PPI::Element

SYNOPSIS

         use PPI;

         # Load a document from a file
         my $Document = PPI::Document->new('My/Module.pm');

         # Strip out comments
         $Document->prune('PPI::Token::Comment');

         # Find all the named subroutines
         my $sub_nodes = $Document->find(
               sub { $_[1]->isa('PPI::Statement::Sub') and $_[1]->name }
         );
         my @sub_names = map { $_->name } @$sub_nodes;

         # Save the file
         $Document->save('My/Module.pm.stripped');

DESCRIPTION

       The "PPI::Document" class represents a single Perl "document". A "PPI::Document" object
       acts as a root PPI::Node, with some additional methods for loading and saving, and working
       with the line/column locations of Elements within a file.

       The exemption to its PPI::Node-like behavior this is that a "PPI::Document" object can
       NEVER have a parent node, and is always the root node in a tree.

   Storable Support
       "PPI::Document" implements the necessary "STORABLE_freeze" and "STORABLE_thaw" hooks to
       provide native support for Storable, if you have it installed.

       However if you want to clone a Document, you are highly recommended to use the
       "$Document->clone" method rather than Storable's "dclone" function (although "dclone"
       should still work).

METHODS

       Most of the things you are likely to want to do with a Document are probably going to
       involve the methods from PPI::Node class, of which this is a subclass.

       The methods listed here are the remaining few methods that are truly Document-specific.

   new
         # Simple construction
         $doc = PPI::Document->new( $filename );
         $doc = PPI::Document->new( \$source  );

         # With the readonly attribute set
         $doc = PPI::Document->new( $filename,
                 readonly => 1,
         );

       The "new" constructor takes as argument a variety of different sources of Perl code, and
       creates a single cohesive Perl "PPI::Document" for it.

       If passed a file name as a normal string, it will attempt to load the document from the
       file.

       If passed a reference to a "SCALAR", this is taken to be source code and parsed directly
       to create the document.

       If passed zero arguments, a "blank" document will be created that contains no content at
       all.

       In all cases, the document is considered to be "anonymous" and not tied back to where it
       was created from. Specifically, if you create a PPI::Document from a filename, the
       document will not remember where it was created from.

       The constructor also takes attribute flags.

       At this time, the only available attribute is the "readonly" flag.

       Setting "readonly" to true will allow various systems to provide additional optimisations
       and caching. Note that because "readonly" is an optimisation flag, it is off by default
       and you will need to explicitly enable it.

       Returns a "PPI::Document" object, or "undef" if parsing fails.  PPI::Exception objects can
       also be thrown if there are parsing problems.

   set_cache $cache
       As of PPI 1.100, "PPI::Document" supports parser caching.

       The default cache class PPI::Cache provides a Storable-based caching or the parsed
       document based on the MD5 hash of the document as a string.

       The static "set_cache" method is used to set the cache object for "PPI::Document" to use
       when loading documents. It takes as argument a PPI::Cache object (or something that "isa"
       the same).

       If passed "undef", this method will stop using the current cache, if any.

       For more information on caching, see PPI::Cache.

       Returns true on success, or "undef" if not passed a valid param.

   get_cache
       If a document cache is currently set, the "get_cache" method will return it.

       Returns a PPI::Cache object, or "undef" if there is no cache currently set for
       "PPI::Document".

   readonly
       The "readonly" attribute indicates if the document is intended to be read-only, and will
       never be modified. This is an advisory flag, that writers of PPI-related systems may or
       may not use to enable optimisations and caches for your document.

       Returns true if the document is read-only or false if not.

   tab_width [ $width ]
       In order to handle support for "location" correctly, "Documents" need to understand the
       concept of tabs and tab width. The "tab_width" method is used to get and set the size of
       the tab width.

       At the present time, PPI only supports "naive" (width 1) tabs, but we do plan on
       supporting arbitrary, default and auto-sensing tab widths later.

       Returns the tab width as an integer, or "die"s if you attempt to set the tab width.

   save
         $document->save( $file )

       The "save" method serializes the "PPI::Document" object and saves the resulting Perl
       document to a file. Returns "undef" on failure to open or write to the file.

   serialize
       Unlike the "content" method, which shows only the immediate content within an element,
       Document objects also have to be able to be written out to a file again.

       When doing this we need to take into account some additional factors.

       Primarily, we need to handle here-docs correctly, so that are written to the file in the
       expected place.

       The "serialize" method generates the actual file content for a given Document object. The
       resulting string can be written straight to a file.

       Returns the serialized document as a string.

   hex_id
       The "hex_id" method generates an unique identifier for the Perl document.

       This identifier is basically just the serialized document, with Unix-specific newlines,
       passed through MD5 to produce a hexadecimal string.

       This identifier is used by a variety of systems (such as PPI::Cache and Perl::Metrics) as
       a unique key against which to store or cache information about a document (or indeed, to
       cache the document itself).

       Returns a 32 character hexadecimal string.

   index_locations
       Within a document, all PPI::Element objects can be considered to have a "location", a
       line/column position within the document when considered as a file. This position is
       primarily useful for debugging type activities.

       The method for finding the position of a single Element is a bit laborious, and very slow
       if you need to do it a lot. So the "index_locations" method will index and save the
       locations of every Element within the Document in advance, making future calls to
       <PPI::Element::location> virtually free.

       Please note that this index should always be cleared using "flush_locations" once you are
       finished with the locations. If content is added to or removed from the file, these
       indexed locations will be wrong.

   flush_locations
       When no longer needed, the "flush_locations" method clears all location data from the
       tokens.

   normalized
       The "normalized" method is used to generate a "Layer 1" PPI::Document::Normalized object
       for the current Document.

       A "normalized" Perl Document is an arbitrary structure that removes any irrelevant parts
       of the document and refactors out variations in style, to attempt to approach something
       that is closer to the "true meaning" of the Document.

       See PPI::Normal for more information on document normalization and the tasks for which it
       is useful.

       Returns a PPI::Document::Normalized object, or "undef" on error.

complete

       The "complete" method is used to determine if a document is cleanly structured, all braces
       are closed, the final statement is fully terminated and all heredocs are fully entered.

       Returns true if the document is complete or false if not.

   errstr
       For error that occur when loading and saving documents, you can use "errstr", as either a
       static or object method, to access the error message.

       If a Document loads or saves without error, "errstr" will return false.

TO DO

       - May need to overload some methods to forcefully prevent Document objects becoming
       children of another Node.

SUPPORT

       See the support section in the main module.

AUTHOR

       Adam Kennedy <adamk@cpan.org>

SEE ALSO

       PPI, <http://ali.as/>

COPYRIGHT

       Copyright 2001 - 2011 Adam Kennedy.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

       The full text of the license can be found in the LICENSE file included with this module.