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PPI::Node(3)	      User Contributed Perl Documentation	  PPI::Node(3)

NAME
       PPI::Node - Abstract PPI	Node class, an Element that can	contain	other
       Elements

INHERITANCE
	 PPI::Node
	 isa PPI::Element

SYNOPSIS
	 # Create a typical node (a Document in	this case)
	 my $Node = PPI::Document->new;

	 # Add an element to the node( in this case, a token )
	 my $Token = PPI::Token::Word->new('my');
	 $Node->add_element( $Token );

	 # Get the elements for	the Node
	 my @elements =	$Node->children;

	 # Find	all the	barewords within a Node
	 my $barewords = $Node->find( 'PPI::Token::Word' );

	 # Find	by more	complex	criteria
	 my $my_tokens = $Node->find( sub { $_[1]->content eq 'my' } );

	 # Remove all the whitespace
	 $Node->prune( 'PPI::Token::Whitespace'	);

	 # Remove by more complex criteria
	 $Node->prune( sub { $_[1]->content eq 'my' } );

DESCRIPTION
       The "PPI::Node" class provides an abstract base class for the Element
       classes that are	able to	contain	other elements PPI::Document,
       PPI::Statement, and PPI::Structure.

       As well as those	listed below, all of the methods that apply to
       PPI::Element objects also apply to "PPI::Node" objects.

METHODS
   scope
       The "scope" method returns true if the node represents a	lexical	scope
       boundary, or false if it	does not.

   add_element $Element
       The "add_element" method	adds a PPI::Element object to the end of a
       "PPI::Node". Because Elements maintain links to their parent, an
       Element can only	be added to a single Node.

       Returns true if the PPI::Element	was added. Returns "undef" if the
       Element was already within another Node,	or the method is not passed a
       PPI::Element object.

   elements
       The "elements" method accesses all child	elements structurally within
       the "PPI::Node" object. Note that in the	base of	the PPI::Structure
       classes,	this "DOES" include the	brace tokens at	either end of the
       structure.

       Returns a list of zero or more PPI::Element objects.

       Alternatively, if called	in the scalar context, the "elements" method
       returns a count of the number of	elements.

   first_element
       The "first_element" method accesses the first element structurally
       within the "PPI::Node" object. As for the "elements" method, this does
       include the brace tokens	for PPI::Structure objects.

       Returns a PPI::Element object, or "undef" if for	some reason the
       "PPI::Node" object does not contain any elements.

   last_element
       The "last_element" method accesses the last element structurally	within
       the "PPI::Node" object. As for the "elements" method, this does include
       the brace tokens	for PPI::Structure objects.

       Returns a PPI::Element object, or "undef" if for	some reason the
       "PPI::Node" object does not contain any elements.

   children
       The "children" method accesses all child	elements lexically within the
       "PPI::Node" object. Note	that in	the case of the	PPI::Structure
       classes,	this does NOT include the brace	tokens at either end of	the
       structure.

       Returns a list of zero of more PPI::Element objects.

       Alternatively, if called	in the scalar context, the "children" method
       returns a count of the number of	lexical	children.

   schildren
       The "schildren" method is really	just a convenience, the	significant-
       only variation of the normal "children" method.

       In list context,	returns	a list of significant children.	In scalar
       context,	returns	the number of significant children.

   child $index
       The "child" method accesses a child PPI::Element	object by its position
       within the Node.

       Returns a PPI::Element object, or "undef" if there is no	child element
       at that node.

   schild $index
       The lexical structure of	the Perl language ignores 'insignificant'
       items, such as whitespace and comments, while PPI treats	these items as
       valid tokens so that it can reassemble the file at any time. Because of
       this, in	many situations	there is a need	to find	an Element within a
       Node by index, only counting lexically significant Elements.

       The "schild" method returns a child Element by index, ignoring
       insignificant Elements. The index of a child Element is specified in
       the same	way as for a normal array, with	the first Element at index 0,
       and negative indexes used to identify a "from the end" position.

   contains $Element
       The "contains" method is	used to	determine if another PPI::Element
       object is logically "within" a "PPI::Node". For the special case	of the
       brace tokens at either side of a	PPI::Structure object, they are
       generally considered "within" a PPI::Structure object, even if they are
       not actually in the elements for	the PPI::Structure.

       Returns true if the PPI::Element	is within us, false if not, or "undef"
       on error.

   find	$class | \&wanted
       The "find" method is used to search within a code tree for PPI::Element
       objects that meet a particular condition.

       To specify the condition, the method can	be provided with either	a
       simple class name (full or shortened), or a "CODE"/function reference.

	 # Find	all single quotes in a Document	(which is a Node)
	 $Document->find('PPI::Quote::Single');

	 # The same thing with a shortened class name
	 $Document->find('Quote::Single');

	 # Anything more elaborate, we go with the sub
	 $Document->find( sub {
	       # At the	top level of the file...
	       $_[1]->parent ==	$_[0]
	       and (
		       # ...find all comments and POD
		       $_[1]->isa('PPI::Token::Pod')
		       or
		       $_[1]->isa('PPI::Token::Comment')
	       )
	 } );

       The function will be passed two arguments, the top-level	"PPI::Node"
       you are searching in and	the current PPI::Element that the condition is
       testing.

       The anonymous function should return one	of three values. Returning
       true indicates a	condition match, defined-false (0 or '') indicates no-
       match, and "undef" indicates no-match and no-descend.

       In the last case, the tree walker will skip over	anything below the
       "undef"-returning element and move on to	the next element at the	same
       level.

       To halt the entire search and return "undef" immediately, a condition
       function	should throw an	exception (i.e.	"die").

       Note that this same wanted logic	is used	for all	methods	documented to
       have a "\&wanted" parameter, as this one	does.

       The "find" method returns a reference to	an array of PPI::Element
       objects that match the condition, false (but defined) if	no Elements
       match the condition, or "undef" if you provide a	bad condition, or an
       error occurs during the search process.

       In the case of a	bad condition, a warning will be emitted as well.

   find_first $class | \&wanted
       If the normal "find" method is like a grep, then	"find_first" is
       equivalent to the List::Util "first" function.

       Given an	element	class or a wanted function, it will search depth-first
       through a tree until it finds something that matches the	condition,
       returning the first Element that	it encounters.

       See the "find" method for details on the	format of the search
       condition.

       Returns the first PPI::Element object that matches the condition, false
       if nothing matches the condition, or "undef" if given an	invalid
       condition, or an	error occurs.

   find_any $class | \&wanted
       The "find_any" method is	a short-circuiting true/false method that
       behaves like the	normal "find" method, but returns true as soon as it
       finds any Elements that match the search	condition.

       See the "find" method for details on the	format of the search
       condition.

       Returns true if any Elements that match the condition can be found,
       false if	not, or	"undef"	if given an invalid condition, or an error
       occurs.

   remove_child	$Element
       If passed a PPI::Element	object that is a direct	child of the Node, the
       "remove_element"	method will remove the "Element" intact, along with
       any of its children. As such, this method acts essentially as a 'cut'
       function.

       If successful, returns the removed element.  Otherwise, returns
       "undef".

   prune $class	| \&wanted
       The "prune" method is used to strip PPI::Element	objects	out of a code
       tree. The argument is the same as for the "find"	method,	either a class
       name, or	an anonymous subroutine	which returns true/false. Any Element
       that matches the	class|wanted will be deleted from the code tree, along
       with any	of its children.

       The "prune" method returns the number of	"Element" objects that matched
       and were	removed, non-recursively. This might also be zero, so avoid a
       simple true/false test on the return false of the "prune" method. It
       returns "undef" on error, which you probably should test	for.

TO DO
       - Move as much as possible to PPI::XS

SUPPORT
       See the support section in the main module.

AUTHOR
       Adam Kennedy <adamk@cpan.org>

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.

perl v5.32.0			  2019-07-09			  PPI::Node(3)

NAME | INHERITANCE | SYNOPSIS | DESCRIPTION | METHODS | TO DO | SUPPORT | AUTHOR | COPYRIGHT

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