NAME

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

INHERITANCE

  PPI::Base
  \--> PPI::Element
       \--> PPI::Node

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::Bareword->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::Bareword' );
  
  # 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 privides 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

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.

children

The children method accesses all child elements lexically within the PPI::Node object. Note that in the case of the PPI::Structure class, 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 child elements.

child $index

The child method accesses a child PPI::Element object by it's 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 'insignifcant' 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.

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 it's children. As such, this method acts essentially as a lexical 'cut' function.

find $class | \&condition

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, or an anonymous subroutine.

The anonymous subroutine will be passed two arguments, the top-level Node being searched within and the current Element that the condition is testing. The anonymous subroutine should return a simple true/false value incating match or no match.

The find method returns a reference to an array of PPI::Element object that match the condition, false if no Elements match the condition, or undef if an error occurs during the search process.

prune $class | \&condition

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|condition will be deleted from the code tree, along with any of it's children.

The prune method returns the number of Element objects that matched and were removed, NOT including the child Elements of those that matched the condition. 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.

cpanm PPI

perl -MCPAN -e shell
install PPI